Temperature and water deprivation and their effect on ... - Nwrc.gov.sa

IIIcontentspageAcknowledgementsAbstractcontentsList of plates <strong>and</strong> figuresI II III VI Chapter one:General introduction1.1 Genus: Gazella 3 1.2 Gazelles of the Arabian peninsula 3 1.3 Ecophysiological studies on the Arabian gazelles11 1.4 Objectives of the study 13 Chapter two:General materials <strong>and</strong> methods2.1 Field work 15 2.1.1 Preparation of gazelles 15 2.1. 2 Metabolic cages arrangements 16 2.1. 3 Radio Telemetry System arrangements 19 2.1. 4 Air temperature <strong>and</strong> relative humidity21 2.1.5 Samples collection 21 2.2 Laboratory work 22 2.3 statistical analysis 23

IV Chapter three:Effect of temperature <strong>and</strong> <strong>water</strong><strong>deprivation</strong> on body temperature3.1 Introduction 25 3.2 Materials <strong>and</strong> methods 29 3.3 Results 31 3.4 Discussion 35 Chapter four:Effect of temperature <strong>and</strong> <strong>water</strong><strong>deprivation</strong> on some of bloodconstituents4.1 Introduction 41 4.2 Materials <strong>and</strong> methods 45 4.2.1 Haematological analysis 45 4.2.2 Serum analysis 47 4.3 Results 51 4.3.1 Haematology 51 4.3.2 Serum constituents 58 4.4 Discussion 73 Chapter five:Effect of temperature <strong>and</strong> <strong>water</strong><strong>deprivation</strong> on some of urine_constituents. ..... .'.':' ,i-." . "" ' ~ i! ;':': :;"$-'" "~~ :- ': :"" ~_ ;;'~'X.' !..-'~. I ' : " . '5.1 Introduction 83 5.2 Materials <strong>and</strong> methods 87 5.3 Results 90 5.4 Discussion 102

v Chapter six:Etteot ot temperature <strong>and</strong> <strong>water</strong><strong>deprivation</strong> on Gazelle's weight, food<strong>and</strong> <strong>water</strong> intake <strong>and</strong> faeces moisture6.1 Introduction 110 6.2 Materials <strong>and</strong> methods 114 6.2.1 Gazelle's weight 114 6.2.2 Dry matter intake 115 6.2.3 Water intake 116 6.2.4 Faeces moisture 116 6.3 Results 1TS'6.4 Discussion 126 Chapter seven: General discussion 131 Referenoes139

VI LIST OF PLATES AND FIGURES pagePlate (1) The general external features of theIdmi gazelle (male). 8Plate (2) Transmitter's implantation in theabdominal cavity of the Idmi gazelle. 20Fig.(l) The metabolic cage which was . especiallydesgined for the experiment. 17Fig. (2) Variation in mean temperature ofgazelles during the experiment in winter. 33Fig. (3) Variation in mean temperature ofgazelles during the experiment in summer. 33Fig. (4) Variation in mean RBCs count ofgazelles during the experiment in winter. 52Fig. (5) variation in mean RBCs count ofgazelles during the experiment in summer. 52Fig. (6) Variation in mean WBCs count ofgazelles during the experiment in winter. 54Fig. (7) Variation in mean WBCs count ofgazelles during the experiment in summer. 54Fig. (8) Variation in mean Hb of gazellesduring the experiment in winter. 56Fig. (9) Variation in mean Hb of gazellesduring the experiment in summer. 56

VII · (10) Var in mean PCV of gazellesdur w 57F • (11) Var mean PCV of gazellesduring the experiment summer. 57Fig. (12) Varion in mean serum Na ofgazelles during the experiment 59F • (13) Var mean serum Na ofgazelles during the experiment in summer. 59· (14) Var mean serum K ofelle dur the exper 61F • (15) Var mean serum K ofzelles the experiment in summer. 61Fig. (16) Varion in mean serum Cl ofgazelles during 63F • (17) Var mean serum Clzelles during the experiment in summer. 63· (18) Var mean serum osmolalityof lIes during experiment in winter. 64F · (19) Var mean serum osmolalityof zelles the summer. 64Fig. (20) Variation in mean serum gofgazelles during the iment in 66F · (21) Var ion in mean serum ofles during the iment in summer. 66F · (22) Var mean BUN of gazelduring the 67

VIIIF. (23) Variation in mean BUN of gazellesthe experiment summer. 67.(24) Variaton mean serum total proteinof les in winter.• (25) Variation in mean serum total proteinof zelles during in summer. 69F. (26) Variation in mean serum albumin ofzelles during winter. 71F. (27) Variation in mean serum albumin ofgazelles during the in summer. 71• (28) variation in mean urine volume ofgazelles thein winetr. 91Fig. (29) Variation mean volume ofgazelles during experiment in summer. 91Fig. (30) VariatNa ofgazelles during experiment in winter. 93Fig(31) Variation in mean urine Na ofgazelles the in summer. 93Fig. (32)mean urine K ofgazel iment in winter. 95Fig. (33) Vargazelles durFig. (34) variationgazelles durFig. (35) variatmean urine K ofexperiment summer. 95mean urine Cl ofthe experiment in 97in mean urine Clgazeldurthe experiment summer. 97

IX F • (36) in mean urine urea of gazelles dur the in winter.98 • (37)in mean urine urea of zel in summer. 98 F . (38) Var in mean osmola of gazelles during the experiment in100 Fig. (39) mean osmolal of lIes during the in summer. 100 Fig.(40) Variation in mean gazelle's weight dur the in 119 Fig. (41) Varduring theIe's in summer. · (42) Var ion in mean dry of gazelles during the in 121 Fig.(43) Variation in mean dry matter intake of gazelles during the experiment summer. 121 · (44) ion in mean <strong>water</strong> les the winter. 123 · (45) Variation mean <strong>water</strong> intake of lIes during the summer. 123 • (46) Variation in mean faecesof gazelles during the experiment winter. 125 · (47) mean moisture of gazel during the experiment summer. 125

GENERAL INTRODUCTION

GENERAL INTRODUCTIONIn most desert areas, mammals in general <strong>and</strong> thelarge mammals in particular face many deterringproblems. The most important of these are the highambient temperature,scarcity of <strong>water</strong> supply inaddition to the high solar radiation (Grenot, 1992).Most of the Arabian Peninsula is dry <strong>and</strong> arid desert,with great variations in atmospheric temperature(Williamson <strong>and</strong> Delima, 1990). This drastic situationof this part of the world has forced its inhabitantanimals to acclimatize <strong>and</strong> adapt for survival. Theyfaced these difficulties by adopting many ways ofadaptation including morphological, physiological <strong>and</strong>behavioral means.These extremely difficult desertsituations areworse for the large mammals that cannot hide like small mammals in order to avoid the highsolar radiation <strong>and</strong> air temperature, in which casethey have to disperse some of <strong>their</strong> body temperature. ' , . '.. ;- . ' ',' ', . , 0 ,'" -, ':' /> /., • '" I 'to the external surroundings ': (Grenot ·~ 1992). It is anecessity for these animals to be able to cope withthese high ambient temperatures without loss of largequantities of <strong>water</strong> (Williamson et al., 1991).Little is known about the ecophysiology of largemammalsinhabiting arid environments, <strong>and</strong> less isknown about the mammals of the Arabian Peninsula,especially the Arabian gazelles. Previous studies~-'.. ­

3were concentrated on tackling different patterns ofbehaviour.1.1 Genus: Gazella.The genus Gazella is part of the tribe Antilopiniwhich belongs to the family Bovidae. Twelve species or-- .~ -more belonging to this genus are scattered alloverthe world (Groves, 1989). The species in the ArabianPeninsula are not thoroughly known, <strong>and</strong> there is someambiguity in the classification due to the scarcity orpaucity of museum specimens, that did not givecomplete geographical variations between thepopulations (Thouless et al., 1991). Linnaeus (1758)was the first to use the scientific nomenclature forthe gazelle, naming an Egyptian one as Capra dorcas.Pallas (1766) gave the species of gazelle describedfrom Syria by Buffon in 1764 scientific name Antilopegazella (Palestine mountain gazelle). This was thefirst scientific reference concerning the Arabiangazelles (Groves,1989).1.2 Gazelles ot the Arabian PeninsulaTaxonomists have differed in classifying themoderate number of gazelles found in the ArabianPeninsula (Groves, 1989; <strong>and</strong> Harrison <strong>and</strong> Bates,1991), but according to Harrison <strong>and</strong> Bates (1991) itcould be assumed that at least four species wereliving in several parts of the peninsula." . . '. ;

4 ~.2.~ G. subgutturosa s<strong>and</strong> gazelle (Rheem)The s<strong>and</strong> gazelle was first described byGuldenstaedt in 1780 as Antilope sUbgutturosa.Gazella s. marica is an endemic subspecies ofthis s<strong>and</strong> gazelle to the Arabian Peninsula. Among thes<strong>and</strong> gazelles, this subspecies is the only one whosefemales possess horns, though they are short <strong>and</strong>straight (Groves, 1989).It is characterized by a relatively large size, shorttail, relatively short ears, with long horns in themale that bend towards each other at <strong>their</strong> extremes,whilst the female has short straight ones. The bodycolour is light clay brown <strong>and</strong> the males have acharacteristic goitre-like swelling at the mid-line ofthe throat (Groves, 1989; Harrison <strong>and</strong> Bates, 1991;<strong>and</strong> Nader, 1989).Distribution:-Gazella s. marica inhabits the s<strong>and</strong>y areas of thecentral parts of the Arabian peninsula, northerngravel plains <strong>and</strong> large parts of the Empty Quarter.The gradual scarcity of rainfall, excessive humanactivity <strong>and</strong> game hunting led to a critical regressionin the number of this gazelle which made it one of thespecies threatened by extinction. This situationlimited the existence of this species to only threeprotected areas, the reserves of AL-Harrah, AL­Khunfah, <strong>and</strong> AI-Tubaiq, <strong>and</strong> the Empty Quarter

5 (Thouless et aI, 1991). There is s probabil ofthe existence of this species on the<strong>and</strong>eastern periphery of AL-Nafud (Nader, 1989).Harr <strong>and</strong> Bates (1991) areas theMiddle East where s<strong>and</strong> lIe occurs such asof Ithe easternof Jordan, inhabiting mainly the s<strong>and</strong>y areas, gravelplains, <strong>and</strong> limestone plateaus, feeding on1dwarf shrubs <strong>and</strong>after rainfall.1.2.2 Gazella dorcas dorcas)It was f described by 1758.Groves (1989) that it a small gazellea shoulder hethat reaches only 60 cm. There are. G . d. la G. d.I'l'he fairly with distinct two stron the s to a black on the nose.It wasalong the Red Sea in Sudan <strong>and</strong> Egyptup to S i Pa in the ofthe Arabian Peninsula ( <strong>and</strong> Bates, 1991).G. d. saudiya a smal subspecies with s<strong>and</strong>ybrowncolour the side face isplainly coloured, ears very long,tail is<strong>and</strong> the horns are long <strong>and</strong> straight in both the male<strong>and</strong> the fema (Groves, 1989). subspecies livedin Arabia on theplains in the eastern

6 side of the Hijaz mountains. It is considered to beextinct in the wild, due to the drastic huntingactivities (Harrison <strong>and</strong> Bates, 1991).1.2.3 Gazella bilkis Bilkis gazelleGroves <strong>and</strong> Lay first described this species in1985. They reported that it is a very dark in colourwith two dark stripes on the sides <strong>and</strong> has thickstraight horns <strong>and</strong> short ears. It is found on thenorthern Yemenmountains with the possibility ofcrossing the Saudi borders (Groves, 1989).1.2.4 Gazella gazella mountain gazelle (Idmi)Pallas first described this species in 1766.According to Groves (1989) <strong>and</strong> Harrison <strong>and</strong> Bates(1991), there are three subspecies of the Idmi in theArabian Peninsula: G. g. cora, G. g. gazella, <strong>and</strong> G.g. muscatensis <strong>and</strong> they render great difficulty todistinguish even for the specialists. However, Grethet al (1993) mentioned that there are four subspeciesoccurring in the southern part of the ArabianPeninsula (G. g. cora, G. g. farasani, G. g.muscatensis <strong>and</strong> G.g. erlangeri). They added that. chromosomesstudies .':4 of ·)~ G:g; ~\"~ cora ·. · <strong>and</strong> ' G ~ g~' ! ! erlangerishowed that <strong>their</strong> numbers are identical to the onesfound in G. g. gazella. Greth <strong>and</strong> Williamson (1994)said that the data on races of G.gazella <strong>and</strong> <strong>their</strong>, .. ,. ,, :~--"

7 ibution are very imprecise. Al Basri <strong>and</strong>:Thouless(1988) in the study on the mounta gazellepopulation of King Khalid WildlResearch Centre(KKWRC) stated that those seem to tothe G. g. gazella.the taxonomicalpos ion of the mountain areunclear, the subspecifwas not taken intoaccount in thstudy.ly . body isII I t <strong>and</strong> has long (Harr <strong>and</strong>Bates, 1991) (plate. 1). The shou height is about 61em I with long in the males (about 22em) having success ly <strong>and</strong> thetampered ends bend towards other. In thefemales, the horns are (11 cm) <strong>and</strong>circu(Groves, 1989 <strong>and</strong> Nader, 1989). Thean oval cross section at the base <strong>and</strong>leI body caserna , but in the females horns have a 1 1cross ( , 1991).The dorsal pelage of the Arabian idmi has alight red, brown colour, <strong>and</strong> atthe mid dorsal zone,1on· the necks to the <strong>and</strong> flanks (Harr <strong>and</strong>I 1991).are two on sides of· the flanksextending along the body, separating the darker dorsal

.n :".,­. ~,,';".'~. , '~ ' ~" ': ;.: '" '~..'; ' 1 .-.:I.~~,. '.; ,J ~f( f"~ ": ' , ,\'.1, .......... :'Io.~ ~ ~ J_:~., ~ ~ :,. ~.J:~'~ : t~ -,~~'t>- . ".1. ,; :' t: ~; ;,',,. . : . ",.. :.'.•i . -,..... " . ",, : .":. >, . ", I .• :..... ..' io..' ~ ....·~?;~(J; ;U':~i;;~" ,~rt' ,: ..' .." ~ ,,.. ..~ ~ ~. ...\'.1' \.)\ ( . (I) '1'11(' ~ lr ~ II C r ('\ J (;;{LCl.ll ;\1 J. c a Lurcs o f t ile 111 .1 1

9 side from the lighter ventral side. There is a brownspot on the nose <strong>and</strong> two white lines on the sides ofthe face (Grove, 1989). The hooves are long <strong>and</strong>pointed at <strong>their</strong> front extremes, <strong>and</strong> the ears arerelatively long. Harrison <strong>and</strong> Bates (1991) havementioned some differences between the threesUbspecies: G.g. cora is smaller in size <strong>and</strong> itshorns are not as straight as those of G. g. gazella,<strong>and</strong> they are also bent strongly at <strong>their</strong> terminals. Inthe case of G. g. muscatensis, the body is larger thanthat of G. g. cora <strong>and</strong> the colour is dark grey withlonger dorsal pelage.Distribution:­The exact distribution of the idmi in Arabia isnot well known (Thouless at al, 1991), but it used tobe found in the mountainous areas , the foothills <strong>and</strong>the coastal plains along the west, southwest <strong>and</strong> southof the Arabian Peninsula, always in association withAcacia trees (Harrison <strong>and</strong> Bates, 1991). Baharav(1974) mentioned its vast existence in Palestine, witha density of 23 gazelle/km 2 ,acting as an epidemic onthe cultural areas. This situation was followed by adecrease in <strong>their</strong> numbers, then again <strong>their</strong> numbers~ ~rose in Palestine. Harrison <strong>and</strong> Bates (1991)havementioned its existence also in some parts of Jordan.The idmi gazelle used to live there in the suitable

10 valley places foothills, rocky open places, inaddition to some s<strong>and</strong>y areas that incorporate Acaciatrees (Thouless et aI, 1991). Baharav (1983) said thatthis gazelle used to live in moderately numbered herdsthat are led by the dominant male.Harrison <strong>and</strong> Bates (1991) mentioned that G. g.gazella inhabits north western Arabia, G.g.muscatensisinhabits south western Arabia, but G.g.cora isscattered in the mountain areas <strong>and</strong> foothills of SaudiArabia including eastern Mecca till the coast near AL­Gunfudah, extending southwards till the northern Yemenborder.The number of idmi gazelle has decreased due tothe aggressive hunting, <strong>and</strong> loss of its suitablehabitats, <strong>and</strong> even was wiped out in some places inArabia, like the narrow coastal plains of Tihama, thefoothills ofAsir, down towards the northern borderof Yemen. There is small number in the Asir NationalPark <strong>and</strong> other places north of Hijaz. The largest wildpopulation of the Idmi is present in the FarasanReserve. It is also present in Yemen(Harrison <strong>and</strong>Bates, 1991).

11 1.3 Ecophysiological Studies on the Arabian gazellesFew studies were done on Arabian gazelles, <strong>and</strong>most of themwere done on <strong>their</strong> taxonomy (Groves,1989, Groves <strong>and</strong> Harrison ,1967, Nader ,1989 <strong>and</strong>Thouless <strong>and</strong> AL-Basri, 199~).Some studies on behaviour were done e.g. the oneby Habibi (1989) at KKWRC concerning dominanceinterrelations of the three species of gazelles: ~~eRheem, the Idmi, <strong>and</strong> the Afri. Another study was doneby Mohammed et ale (1991) on the natural diet of Rheemgazelle.Ecophysiological studies (e.g. <strong>water</strong> intake) weredone byWilliamson <strong>and</strong> Delima (1991) on G. gazella<strong>and</strong> G. subgutturosa at KKWRC. Williamson et ale (1992)also done some work on the Arabian s<strong>and</strong> gazelle,G. subgutturosa in relation to temperature.In addition to the previous studies some workhave been done on non-Arabian gazelles <strong>and</strong> otherdesert animals, mainly on the Afri gazelle <strong>and</strong> thecamel. Ghobrial <strong>and</strong> Cloudsley-Thompson (1966) studiedthe <strong>effect</strong> of <strong>water</strong> <strong>deprivation</strong> on the Afri gazelle(G. dorcas) in Sudan. Schmidt-Nielsen et ale (1967)studied <strong>water</strong> <strong>deprivation</strong>, <strong>and</strong> temperature <strong>effect</strong>s onmetabolic rate <strong>and</strong> the weight specific temperaturemetabolic rate on the Arabian camel, Camelusdromedarius. Ghobrial (1970b)worked on the <strong>water</strong>relations of the Sudanese Afri gazelle <strong>and</strong> Taylor

12 (1970a) stud the a temperature <strong>and</strong><strong>water</strong>ion on the thermoregulation ofhoofed mammals ( ). (1972) also workedon <strong>water</strong> needs for G. thomsoni <strong>and</strong> G. granti inrelat to to desert life.were done on the Sudanese sheep,gazel <strong>and</strong> the ( etal. I 1984; I, 1976 i <strong>and</strong> Osman la,1974). Mohammed et al. (1988) have done a on theSudanesegazelle concerning thermal relations<strong>water</strong>Ahmed (1994) onconcerning <strong>water</strong> iction <strong>and</strong> onion <strong>and</strong> some bloodIn the , more attention paid onone of means environmentalons, namely physio1onshave been adopted by the mountain gazelPeninsula.la (Pal 1766)

GENERAL MATERIALSAND METHODS

15GENERAL MATERIALS AND METHODSwork was at the Khalid wildlifeResearch Centre (KKWRC) at -Thumamah which about80 Km North of Riyadh, Saudi Arabia.This work comprtwo2.1 Field WorkIn this partIs <strong>and</strong> the metabolof the experimentalwas done in additionto the2.1.1 Preparation Gazelles:adult males ( la la) wereselected for this study. were about 1-2<strong>and</strong> <strong>their</strong>17-21 Kgs. They werefrom the main enclosure of KKWRC. Animals weremed 1 by , <strong>and</strong> accl izedfor 11 weeks ior to experimentation. werehoused f 3 x 4 m eachgood light <strong>and</strong> aeration. The stables were arranged insuch a way that to 1 ina 1which had been covered by dry s<strong>and</strong>;<strong>water</strong> werewereleft for further 4 weeks for acclimation withcontinuous observation., ! !•~

16 2.1.2 Metabolic Cage Arrangements:six metabolic cages measuring 110 cm in length<strong>and</strong> 165 cm in height were used in this study. Fivecages were used for collection of the gazelle'sexcreta (droppings <strong>and</strong> urine). The sixth one was usedfor assessing the amount of urine <strong>and</strong> <strong>water</strong> lost (seechapter 5 <strong>and</strong> 6). These metabolic cages we~eprovidedwith four shelves on, different levels:-, .; I. I1- The Lower level (Ll):­This level is made up of a metal plate, about 20cm of ground level.It is made in the form of a bigfunnel that converges to the centre, where asmallhole is connected to a ranged bottle via a tube tocollect urine. This level is 70 x 40 cm i movable <strong>and</strong>adjustable with the above second level.2- The Second level (L2):­There is a wire mesh whose dimensions are 70 x 40cm, the mesh opening is 2 x 2 mm, which is situated 20cm higher than the first level. It is movable <strong>and</strong> itsmain objective is to collect the dropp~ngswithoutretention of the urine.3- The third level (L3):­This Level is made of two parts, the smaller oneis square shaped made up of wood whose side is 40 cmlong. This is situated in the front part o~ the cage.The other part is made in the form of ~etalfor the gazelle to st<strong>and</strong> on.inettingIt has medium sizedopenings (10 x 10 mm) <strong>and</strong> dimensions of 70 x 40 cm. It. :. ,.. . !. i 'j'~ , jIi

17 METAL MESH- --~--- '/"­~"" ~ 110 em.~ ---------~==----------- -~L4o 0o~------~'-r---------------7r-'r-~ 020cm.Eu10DOOROPENINGMETALMESH//./././- -71// IIIr-­__-.­IIIIIt-: 'i.!Eu 'o~ .EugNEu0NL3METALMESH_L2METALFUNNEL-­L 10•0­0FOOD a WATERCONTAINER25mm It'l

18 . \;is specifically made for the hind limbs of thegazelle, hence faeces<strong>and</strong> urine can pass through.This level is non-movable <strong>and</strong> situated 15 cm above thelevel beneath.4- The fourth level (L4):­A metal netting with large openings (4 x 4cm)was situated 115 cm above the third level,specifically made to hinder the animal from leavingthe cage.In the front part of the cage, food <strong>and</strong><strong>water</strong> container was situated at the dimensions of 70x 40 x 20 cm, i.e. 70 cm above the third level.Thelower part of the container is divided into twosmaller ones.One is 10 x 20 x 15 cm for <strong>water</strong> <strong>and</strong>the other one is 15 x 25 x 20 cm for food.On theback side of the cage is a door for letting the animalin <strong>and</strong> out (Fig.I).The cage is well aerated, <strong>and</strong>allows the animal slight movements, but does not allowit to reverse its direction. The cages were situatedunder a shaded building whose roof was about 4.5 mhigh, open at . three sides <strong>and</strong> the cages were 4 mapart.After the first acclimation, the animals weretransferreu tc the five cages <strong>and</strong> they . were givenenough food <strong>and</strong> <strong>water</strong>, ad lib. for two weeks in order,\to acclimate to live in the cages. The :animals wereweighed on a sensitive electronic Seca balance(accurate to 50 g) before being distri~utedcages.in the~-......_-.

19 . 2.1.3 Radio Telemetry System Arrangements:o Telemetry System (RTS) was by theAmer Tel Company. TheRadio receiver, a pulse intervalof<strong>and</strong> five waxcoatedthat ffer s Is (see3) • The were ibratedfor . Each wassurgicalabdominal cavity of the gazellesthrough a small opening (5-7 cm)(plate.2). The wholewas functioning, recordinggazelle's bodyfrom time to time without anyto them. 1 the were done bydoctors from KKWRC.ionwere shito1 wasalone.They were observed <strong>and</strong> followed up for fourweeks till complete recovery.toanimals were thenoncemore for a week. The anima were weighed before <strong>and</strong>afterThe animals were used as control group at theas an1group afterwards.Each gazelle was placed in ametabol cage I fed <strong>and</strong> <strong>water</strong>ed ad 1 for5during <strong>and</strong> summer. Ga les were un<strong>water</strong>ed for8 during winter (January) for .3 days in," j.summer (July) <strong>and</strong> 24;11:, ' bothper:1~ , ;' '

} ()or II,,' l clilli q il7,r] Ie'.

; ,21 2.1.4 <strong>Temperature</strong> <strong>and</strong> Relative Humidity:­The <strong>and</strong> the therelat humid were from themeteorolog 1 at KKWRC (about 100 m from thegazelle s). In addition to that athermometer wasclose to the gazelle's sto record the air temperature 2 h 6 am - 6pmsummer.2.1.5 Samples Collaotion:­Blood, <strong>and</strong> were colduring th in winter (January) <strong>and</strong> summer(July) as llow:2.1.5.1­ Blood .­Blood samples were collected once.dayall in summerf 5 days of the beginning of theDuring <strong>water</strong> ion, blood was col onceeveryday in winter; <strong>and</strong> once every 24 h duringsummer.During both seasons blood samples were2 h 24 h rehydrat In both seasons,blood were col from animal at thesame tof theBlood samples were collected by the j~gularveinof the animals 3 ml tubesDiamine(EDTA) as anfor I into(10II '

22 vacuta in tubes for serolog 1 tests. Alltubes were suppl by Meylan Cedex.2.1.5.2- Faeces Col :­In both seasons, fresh faecalfrom allan Is were collected once 24 h theus the second mesh layer of themetabol just after dropping. Faecalwere we p in covered <strong>and</strong>taken to the oven for drying.2.1.5.3- Ur Collect :­In both seasons allwere collected24 h from each animal using the Lower levelif 1 made for objective.Every morn ur were colfrom each animal <strong>and</strong> taken to the <strong>and</strong> at4 °C for 1 ana is.2.2 Work:­2.2.1 Transmitter's Calibration:­Thebeen calthe laboratory before being fixed in the animals.were cal by ing them ina var A 1regression as the variable,<strong>and</strong> the pulse 1 as the dependent var wasThis relatthe pulse interval to anbe calculated from0.1 °C.

23 2.2.2 Blood <strong>and</strong> Urine Analysis:­• ;, ,:; : IBoth blood <strong>and</strong> urine tests were done at thelaboratory.For serological <strong>and</strong> biochemical testsserum was separated from the whole blood afterclotting <strong>and</strong> centrifugation at 3000 rpm for 10 min_The sera were kept at -20°C prior to serologicalanalysis. Haematological tests were done right aftercollection of the samples. Urine analysis was doneaccordingly (see Chapter 4 <strong>and</strong> 5).2.2.3 Faeces Drying:­Faecal samples were weighedfresh <strong>and</strong> afterdrying in an electrical oven at 105°C to assess <strong>their</strong>moisture.2.3 statistical AnalysisMinitab, Inc (1989) statistical Program was used foranalyzing the results of body temperatures, bloodconstituents, urine constituents, gazelle's weights,<strong>water</strong> <strong>and</strong> food intake <strong>and</strong> the faeces moisture.Analysis of variance (ANOVA)<strong>and</strong> Covariance (COVA)were used for comparing the results of the threephases (Hydration, dehydration <strong>and</strong> rehydration) duringthe two seasons (winter <strong>and</strong> summer). Harvard graphics programme was used for plotting the graphs <strong>and</strong> the st<strong>and</strong>ard deviation is given on each graph (figs 4-47).

CHAPTER THREE OF TEMPERATUREAND WATERDEPRIVAl'IONON BODY TEMPERATURE

25 3.1Louw <strong>and</strong>(1982) mentioned that most of theare by insolat <strong>and</strong>high in addition to highlyelevated substratum temperatureexceeds 55°C insummer. This situation always accompanied acutelevel. Thus, 1environments have to to res thisthatfollowtwoto resthetemperature.The smaller animals allow <strong>their</strong> bodytemperature to fluctuate extens, whilst keepingrate of at On other, the ungulates is toatatthe morning, then allowing• Theat , ne allowing forbody temperature nor for humidity.Taylor (1970a) that some an like's Ie ( ), Thompson's gazelle(Gazella thompsonii) , the oryx (Oryx ), thecan 10 ) 1 wildbeest<strong>and</strong> the Zebra have elevatedbe ambient temperature (40-50 0 C), whilst no change had .,

26 '- ..... ­been observed on the other group of animals that weregiven <strong>water</strong> freely.The author also added that thelevel of evaporation was lower when the animals wereun<strong>water</strong>ed. Schmidt-Nielsen et al. (1967)mentionedthat un<strong>water</strong>ed camels allow <strong>their</strong> body temperature tofluctuate up to a difference of 6°C, whilst it is only2°C when they are <strong>water</strong>ed. He also found out that<strong>their</strong> metabolic rate is related directly proportionalto <strong>their</strong> body temperature but this relationship isreversed when the camel is un<strong>water</strong>ed, as the rate ofdehydration is inversely proportional to the metabolicrate. Musa (1978) assumed that one of the majorfactors that enables the camel to endure dehydrationis its ability to allow its body temperature to varyextensively, a situation that could enable it to copewith external surrounding temperatures.Ghobrial <strong>and</strong> Cloudsley-Thompson (1966) mentionedthat the Afri (G. dorcas) could endure a period of 12days of dehydration at low air temperature (10-30°C)<strong>and</strong> a relative humidity of (25-40%). When theconditions deteriorate (high air temperature (35-45°C)<strong>and</strong> low relative humidity (10-30%)) these gazelles cannot survive for more than 5 days. Cloudsley-Thompson(1969) found out that dehydration of this speciesseverely affects its body temperature that lead to abreak in its system of thermoregulation..~ .

27 In astudy of the skin tissue of the Afri,Ghobr 1 (1970a) confirmed the presence of <strong>and</strong>(1970b)inedthat when the a exceeds the rectalin the Sudanese G.dorcasdissipates theexcess metabol <strong>and</strong> airthe rate of evaporation asincreases therate of <strong>and</strong>I whenanimal dehydrated allows its body temperature torup to 6°C, in order to evade evaporation <strong>and</strong>to a minimum. I (1974) aAfri usually started to at an air temperatureof 25 ° C,at a<strong>and</strong> the highest rate of evaporation tookbetween 30 <strong>and</strong> 35°C.(1972) found out that when the a45°C, the G. i <strong>and</strong>G.granti would notexcessfrommeans ofevaporation. When a of <strong>water</strong>, thesespec allow ir toexcessively whilst keeping <strong>their</strong> brainatthe normal I (197 the<strong>and</strong>Jerboa could live without taking<strong>water</strong> directly, as they reshighthrough behavioral thermoregulation in a way that theybecome nocturnal, I the act to thewhen the temperature drops <strong>and</strong>

28 humidity r . Ghobrial (1974) also explained thatthe Sudanese Afri gazelle selects the cooler hours ofthe for act during summer <strong>and</strong> , <strong>and</strong>retreats to the shade when thetemperature iselevated to reduce ; She aobserved that there was no shours bothbodysummer <strong>and</strong>winter when conditions were normal; but when thean 1 was then the becameconspicuous <strong>and</strong> reached 2°C. Mohammed et ale (1988)reported that there was no meaningful difference inrectal i zelle,<strong>and</strong> he referred to of todiss body temperature. The study done -EYwill et ale (1992) on the Rheem zelleexplained that the varion in bodying i anima werereached 2.5 °C, whilst thdifference was only onein case of <strong>water</strong>ed ones. They alsoin body temperature betweenthe dehydratedmore enhanced when thea exceeds 39°C. They also reported thatthe of the in the dehydratedIs was less than that ofcamels which reachedreferred that to the abilof the camel tostore heat in body <strong>and</strong> it only when thea

29 3.2 Materials <strong>and</strong> Methods:­of all theIs was recordedonce 2 h from 6 am to 6 pm summer<strong>and</strong> . These readings Were taken daily ing thethree of the (<strong>and</strong> rehydration). The Radio Telemetry (RTS)was used as by Will (1992) •Briefly, the made up of a receiver,a pulse interval timer (accurate to 1 11 <strong>and</strong>a zed, which sends outpulses by that vary directlyproportional with temperature.Thewerethem in a laboratory which thewas var so that a 1could be plotted, with temperature as the independent<strong>and</strong> Se as varUs this relationship, temperature could becalcu from pulse 1 to an of O.l°C(Will <strong>and</strong> Delima, 1990). After calibration,transmitters were into abdominalzelly. Thus within half an hourthe tter will measure gazel bodyThrough anfixed near thegazel 's sheds, s Is could bereceived asthat could

30transformed by the pulse interval timer to readablenumbers that are changed according to the change intemperature.statistical Analysis:-Minitab, Inc (1989) statistical Program has beenused. Body temperature of all test animals for thethree phases of the experiment, during both summer <strong>and</strong>winter were included in the calculation. Analysis ofvariance (ANOVA) <strong>and</strong> variance were used for comparingthe three phases during the two seasons.Comparisonof the results at different times of the day to seethe variation in body temperature when <strong>water</strong> wasavailable.Also comparison of the results of the<strong>water</strong>ed animals phase, the <strong>water</strong> <strong>deprivation</strong> phase,<strong>and</strong> the rehydration phase during summer <strong>and</strong> winter, tosee the differences between them. The summer resultswere also compared with the winter results to see thedifferences in body temperature in relation to theexternal temperature factor.,: \

31 3.3: Results:a) Winter:­In winter the air temperature ranged from low 3­8°C to maximum of II-19°C. The relative humidity washigh; (61-97%) in the early hours of the morning, <strong>and</strong>low (35-54%)later in the day. In such conditions,with the presence of <strong>water</strong>; no wide range differencehad been observed in the body temperature of thegazelles (~0.2 °C), especially during the day (6 am ­6 pm)), as the body temperature ranged between 39.4°Cat 8 am <strong>and</strong> 39.6°C at 4 pm. But, a significantdifference of 1.3 °C (P::;0.05, F=8.24) was noticedwhenthese animals were given enough <strong>water</strong> afterdehydration fig(3). It was observed that the animalsbody temperature was lowest (38.6 °C)at the earlymorning (6-8 am), then gradually rises to its maximum(39.4°C) at 6 pm. It was noticed that when thesedehydrated animals were rehydrated a substantialdecrease in <strong>their</strong> body temperature occurred, as thebody temperature decreased to 38.3 °C after 2 h ofrehydration. This decrease in body temperaturecontinued untill the animals reached <strong>their</strong> normallevel of body temperature, 10 h after rehydration .. 1

32 b) Summer:­In summer the atmospheric temperature ranged froma minimum of 26-28°C <strong>and</strong> a maximum of 42-44°C.Therelative humidity was 38-40% in the early hours of themorning <strong>and</strong> was as low as 20-30% in the late hours ofthe day.In such conditions when the animals weregiven enough <strong>water</strong>, there was no significant variationin <strong>their</strong> body temperature (0.5°C), as the bodytemperature ranged between 39.6°C at 6 am <strong>and</strong> 40.loCat 6 pm, <strong>and</strong> hence the hot weather did not affect theanimal's body temperature as long as <strong>water</strong> wasavailable.But, when these animals were dehydratedfor consecutive 3 days, a significant (psO.Ol,F=ll.98) variation was noticed (2.1°C) during the day.It was noticed that the lowest animal body temperature(39.5°C) was in the morning (6-8 am.) <strong>and</strong> the highest(41.6°C) was in the afternoon (4-6 pm.) Fig(3) .When the animals were rehydrated once more, <strong>their</strong>body temperature dropped a little (0.1 DC)then rosewithin two hours to follow the same pattern as beforedehydration.The results show that the animal's bodytemperature, with the availability of <strong>water</strong> did notvary significantly (P~0.912,F=0.ll107) during winter<strong>and</strong> summer. The variation was 0.2°C in the morning <strong>and</strong>0.7°C in the late afternoon.

31 40Hy

34 The difference in body temperature wassignif in case of the dehydrated group ( 0.010;F= 16.29). The var was 1.10C theearly hours of the morning <strong>and</strong> was up to 2.4°Cthelate hours of the day. The variation wasinsignif (P20.422, F=0.77) after ion ofthe an 1s during the two seasons, <strong>and</strong> summer.

35 3.4. Discussion:­It appears that when G.gazella was given dryfood (moisture content 8-13% during winter, <strong>and</strong> 3-5%in summer) should have free <strong>water</strong> to drink.It couldendure the absence of drinking <strong>water</strong> for variousperiods of time <strong>and</strong> this situation depends upon theconditions of the air temperature <strong>and</strong> the relativehumidity.The gazelle would survive for 8 days inwinter when deprived of <strong>water</strong>, that was when themorning air temperature was 3-8°C <strong>and</strong> the afternoonair temperature did not exceed 11-19°C with relativehumidity of 61-97% <strong>and</strong> 35-54% in the morning <strong>and</strong>afternoon, respectively.In the extreme conditions of summer, when themorning <strong>and</strong> afternoon air temperatures were 26-28°C<strong>and</strong> 42-44°C, respectively <strong>and</strong> relative humidity 38-40%<strong>and</strong> 20-30%, respectively, gazelles could onlywithst<strong>and</strong> 3 days of dehydration. At thi~point, allanimals were very weak, drowsy <strong>and</strong> very emaciated. Inaddition to that, a degree of eyeball retraction <strong>and</strong>skin turgor wasnoticed. Similar conditions werereported by Gary et ale (1979) on horses <strong>and</strong> Mohamed(1986) on dorcas gazelle during <strong>their</strong> studies of the<strong>effect</strong> of dehydration in summer season. Comparison ofthe dehydration's periods during winter <strong>and</strong> summerrevealed a great difference in the gazelles enduranceof dehydration. The animals survived dehydration in

36 winter 2.7 t more than the summer. Th could beattr to the difference thethat affects<strong>and</strong> hencebody <strong>water</strong> balance through evaporation ( I,1966; 1967;19 2, (1970b)<strong>and</strong> Taylor (1972) that the of evaporationto animalThe resu showed that body of1the gazelles not vary the winteras the difference was only O.2°C.The samesituat was also summer whenthe <strong>water</strong> waslable, as the difference was onO.5°C. This shows that these Is could ma in asteady body temperature when<strong>water</strong>availabwithout being muchexternalmakeuse of to ma body1,1970b).summer,tend to use evaporation to reduce <strong>their</strong> body(Taylor, 1972 <strong>and</strong> '"'......,........ ial, 1974).Theismisdissipat of excess body theiz of the surface 1 ofthe lungs, mucous membranes, the nose <strong>and</strong>skin (by), <strong>and</strong> hence the ( , 1972).During winter dehydration,animals did notshow signif the as

37 the difference was only O.8°C.Thus, the animals didnot allow for much decrease in <strong>their</strong> body temperature,although the air temperature was low. This isprobably because the animals tend to take more food(while dehydration), in addition to using <strong>their</strong> ownbody fat to produce excess heat energy to counter thedrop of the air temperature <strong>and</strong> succeed to keep asteady body temperature (Tietz, 1987).The opposite situation was seen when the animalswere dehydrated in summer as they allowed for greatervariation in <strong>their</strong> body temperature (2.1°C) during theday.A directly proportional relationship has beennoticed between the air temperature <strong>and</strong> the animalbody temperature during the last periods ofdehydration.This was seen when the lowest animalbody temperature was 39.5°C when the air. temperaturewas 28°C, <strong>and</strong> the highest recorded animal bodytemperature was 41.6°C when the air temperature was41°C at 4-6 pm. It could be explained that thisvariation was accomplished in <strong>their</strong> attempt to reduceevaporation through respiration <strong>and</strong> sweating duringhigh body <strong>and</strong> air temperature in the day. Similarresults were obtained by Ghobrial(1970b) on Afrigazelle <strong>and</strong> Taylor (1970b) on Thompson's <strong>and</strong> Grant'sgazelles. When the air temperature starts to drop inIthe afternoon <strong>and</strong> night, the animals dissipate <strong>their</strong>body heat to the environment to reach the lbwest~ : . i :' ."' t ;.,.• ' ~ j •

38 possible body temperature without much loss of body<strong>water</strong> through respiration <strong>and</strong> sweating. 'I'hesezelles by so doingdesert mammals.These results are in goodwith (Ghobrial, 1974; I 1970a,1970b, 1974; Williamson et a1., 1992 <strong>and</strong> Zari <strong>and</strong> AL-Hazmi, 1993) as they reported that theofthe rectalof the Arabian5 °e during summer days.One ofmain factors that allows the Idmizelle to sustain high bodyisthe panting mechanism.These gazelles could cool theblood coming to through thatbl to coo nasal mucosa by (LouwSee , 1982). This process is exh by many ofas an an1 Most <strong>their</strong> blood going tothe brain is via the 1 carotidThisinto numerous arteriolesblood 1 pass the nasal open<strong>and</strong> mucosa, then reunite before supplying the brain.When blood smallit is cooled down by evaporation of respiration by 3°ebefore the bra ( , 1972).When the animals were rehydrated in winter, adrop of O.3°e in body wasThis cou be attributed to that these

39 animals took alot of cold <strong>water</strong> (1099 mI/2h), ofwhich the temperature was 'not measured ' but may notexceed 4°C.This situation might have lowered <strong>their</strong>body temperature for a period of 4 h. After 10 hr ofrehydration,animals body temperature returned tonormal. The case was different when these animals wererehydrated during summer, as there was nodrop ofbody temperature, probably due to the optimum <strong>water</strong>temperature (29°C) <strong>and</strong> hence did not affect theanimal's body temperature.. : 1

CHAPTERFOUREFFECT OF TEMPERATURE AND WATER DEPRIVATION ON SOME BLOOD CONSTITUENTS ' . I .: . ". , ,t,:, ' .

41 4.1 Introduction:There are no studies on the blood constituents ofthe Idmi Gazelle, G. gazella under dehydrationcondition. This also applies to the rest of theArabian gazelle species. There are very limitedstudies on other non-Arabian gazelles, e.g. theSudanese Afri G. dorcas in addition to other desertmammals. The study of Ghobrial <strong>and</strong> Cloudsley-Thompson(1966) on G. dorcas in Sudan showed an increase inthe urea level in the dehydrated animals (5 days insummer), when the range of air temperature was 35­45°c, <strong>and</strong> the relative humidity was 10-30%. The urealevel increased from a range of 5-10 mg/100 ml to 70­110 mg/100 mI. An increase was also noticed in thelevel of haemoglobin (Hb) <strong>and</strong> packed cell volume (PCV) ,from a range of 14-18 g/100 ml to 20-29 g/100 ml; <strong>and</strong>from a range of 4.5-5.5 g/100 ml to 5.5-7 g/100 ml,respectively. The study of Couldsley-Thompson (1969)on blood parameters of dehydrated G. dorcas indicatedan increase in blood urea that reached 11-14 timesmore than the level of the non-dehydrated gazelles.Also the Hb <strong>and</strong> PCV levels increased by 30-39% for Hb<strong>and</strong> from 40-55% to 55-59% for PVC.Mohammed et ale(1988) have done a similar study on the same gazelleafter dehydrating the animals for 10 i ,days then'. j 1:'rehydrated them for 2 days. Significant: increase in,' , ! ''1' I .the levels of Hb <strong>and</strong> albumin up to 34% ~rtd, 18%,I. ., , I:

: I ~ I42respectively, were recorded. They added that theconcentrations of Na+, K+ <strong>and</strong> Cl- were also increasedby23%, 44%, <strong>and</strong> 18%, respectively, in the dehydratedgazelles. After rehydration these levels restored<strong>their</strong> previous levels. In the study of MacFarlane etal. (1961) on dehydrated Merino Sheep (5 days insummer under maximum temperature of 39-42.2°c), theanimals lost 45% of the total plasma volume, the bloodvolume decreased by 30%, the PCV increased by 39%, theHb increased by a ratio of 43%,the plasma proteinincreased by 60%, Na+ increased by 10%, <strong>and</strong> the Ureaincreased by a ratio of 42%, compared to the levelsbefore dehydration.Brown <strong>and</strong> Lynch (1972) in <strong>their</strong> study on Mernioewes had shown that low uptake of <strong>water</strong> producedlimited <strong>effect</strong>s on the levels of Blood Urea Nitrogen(BUN). They found out that Na+ concentration washigher in November than October. Moreover, when sheepwere dehydrated, variation in PVC was insignificant.This was due to the high level of humid foodOsman <strong>and</strong> Fadlalla (1974) found that there was asignificant increase in the level of BUN of the desertsheep when they were short on <strong>water</strong>, compared to thosethat took <strong>water</strong> ad Lib. They also foundthat the BUNlevel increased by 14% in animals fed on Alfafa hay<strong>and</strong> deprived of <strong>water</strong>. A slight decrease o( BUN was1:.

43 not an Is fed on Alfafa <strong>and</strong> <strong>water</strong> ad Lib.When the black Bedouinwere dehydrated till theylost 25-30% of <strong>their</strong> body weight <strong>and</strong> thenChosn <strong>and</strong> Shkoln (1977) found that theosmolal signif decreased from 336.5 ± 6.7 to303 . 7 ± 7. 5 mOsm/kg a 7 h of ion. Thestudy of Musa (1978) on Camels, desert <strong>and</strong>desert had shown that of Camelsreflected var of as was~15%, serum osmolality was 7 ". In desertserum total in concentration had by21%, Albumin by 1 by27% <strong>and</strong> serum osmolal sed by 12% when theyrefof serum total protein, serum albumin,serum urea, serumNa+ <strong>and</strong> serum osmolality by ratiosof 19%, 12%, 63%, 18% 9%,Gary et (1979) found out a s ficantincrease in the of f <strong>and</strong> osmolality inthe plasma of the the Isof K+, ca+, <strong>and</strong> Mg+ remained unchanged. Sin the concentration of 1 plasma inwas noticed. There was a marked decrease in<strong>and</strong> osmolal when the Is wereICl-rema constant. When¥u~oHinaket a1. (1984) dehydrated the black11 25 3 body

44 Ithe blooddecreased after 4 h of by 29 kg theyalso nota 9.5 mmol/l <strong>and</strong> a 8.0 mmol/l decrease inof Na+ <strong>and</strong>, respectively. Noon theof blood urea <strong>and</strong> K+ wasafterMa z et . (1984), on thereported a signif in the plasmaosmolalof a 4 days dehydrated lactating or non­1 They noticed an inplasmalevel from 141 ± 1 mmol!l to 162.2±2 mmol/l;<strong>and</strong> from 146±0 mmol/l to 164±1 mmol/l<strong>and</strong>non-l ones, ively. was nosfone hour ofanimals approached normal 1, but thenon-lactating ones took longer t to reach s larone hourrehydration both lactating<strong>and</strong> non-lactatingIsconcentratSneddon et al. (1993) had found that thedehydrated Namib horses <strong>and</strong> Boerperd 14.3%<strong>and</strong> 14.2% of the total body <strong>water</strong>, iva . sixof the lost <strong>water</strong> wasI27% of 1 spaces <strong>and</strong> 67% from thecombined intracellular transcellular space. They afound out that the osmolal significantly" I: ,.

45 increased during dehydration , then rapidly decreasedto reach the normal previous level within 3 hours inboth types of horses.4.2 Materials <strong>and</strong> MethodsWork was done in two main parts:The first part was done in the field (see chapter 2)<strong>and</strong> the other was done in the laboratory. In thelaboratory two types of analyses were made.4.2.1 : Haematological Analysis:Blood samples for Haematological analysis werecollected by Jugular vein puncture into 3 mlvacutainer tubeswith L Ethylene ~ DiamineTetra Acetate(EDTA)as an anticoagulant. (Supplied by DickinsonFrance) .4.2.1.1 Red Blood cells (RBCs) <strong>and</strong> white Blood cells(WBCs) counts:RBCs <strong>and</strong> WBCs counts were done using ZM Coultercounter from Coulter Electronics LTD (Northwell Drive,Luton,Engl<strong>and</strong>). Blood samples were diluted usingbuffered isotonic saline (Isoton II) from coulterelectronics. Different settings were used foranalyzing RBCs <strong>and</strong> WBCs. RBCs setting would' rot allowWBCs to pass through, <strong>and</strong> counted with RBCs~ ! RBCs wereHaemolyzed using Zap-Oglobin (from Coulterelectronics) in order to count WBCs without RBCs. . I II

46interference after changing the setting to WBCs mode.Reading were recorded directly from theCalculatCalculation for RBCs <strong>and</strong> for WBCs were done asfollows:-RBCsSum of 4 readings,WBCs = mean of 2 readings, /1.4.2.1.2: Packed cell volume (PCV)PCV was measured the Microhaemotocrmethod as Ja (1986), us theMicrohaematocr centrifuge from Heraeus GMBH­. The 1 tubes were centr at 12000rpm.PCV was from the scale inpercentage.4.2.1.3: (Hb was determined using the SpectrophotometrCyanmethemog method as Jain (1986).Drabkins-Rea~ent was obtained from bioMerieux Marcy L, Etoile-France. Spectrophotometer wavelength was adjusted at 540 nm. valuesHb were calculated as follow: Hb concentra on 1)=xHb concentration of the st<strong>and</strong>ard (gIl).

47 4.2.2: Serum analysisBlood were col by vein10 ml vacutainer plain tubes (fromBecton D ) .Whole bloodwere left for about 30 minutestill get clotted complete Serum wasfrom the i of the bloodfugation at 3000 rpm for 10 minutes.Serum were kept a freezer at -20°C untilanalyzed later.4.2.2.1. Determination of serum sodium (Na+)potassium (K+):were determined using Na/K analyzer, Orion1020, (Or Inc. Products,Boston, USA), Orion 1020 Analyzer measuresNa+means of se eCalculation:The Na/K er g the in mmol/l4.2.2.2. Determination of blood urea nitrogen (BUN):BUN concentrat were measured us the seralyzer111 from Ames sion, Miles Inc. ,USA, us reaction of 0­I as by (1974) •Serum were di 1 in 3.

48The results were read directly from the seralyzerIII in mg/100 ml, a correction factor of 0.3581 isapplied to convert the units in to mmol/l.4.2.2.3: Determination of Glucose: Glucose concentration was measured using the seralyzer III from Ames Division, using Hexokinase method as described by Henry (1974). Calculation: Values were read directly from the seralyzer III, the units obtained were in mg/100 ml, a correction factor 0.0555 was applied to convert the units in to mmol/l. 4.2.2.4: Determination of chloride concentration(CI-) :Chloride concentrations were measured usingspectrophotometer (from spectronic 601 Bausch <strong>and</strong>Lomb-Milton Roycompany-USA.) at wavelength 460 nm,using chlorofix kit (from A.menarini, DivisioneDiagnostici: Firenze, Italy).The method used fordetermination of CI-is the modification of Schales<strong>and</strong> Schales (1974) which involves using the excess ofthe poorly dissociated mercuric thiocyanate as theprimary reagent. This forms mercuric chloride leavingthyiocyanate ions in solution which then react with aferric salt. The colour produced by t~e red ferricthiocyanate is measured (Gowenlock, 1988) ~

49 Reaction sequence as follows:6 Cl- + J Hg(Scn)2 ~ JHgCl 2 + 6SCN- + 6SCN­6SCN- + 2Fe 3 + ~2Fe(SCn)3Absorbance of SampleAbsorbance of st<strong>and</strong>ard x 345. 45mg/ 100ml345.45 mg/100 ml = concentration of cl- in the st<strong>and</strong>ard sodium chloride. A correction factor of (0.2821) was applied to convert the unit in to mmol/l. 4.2.2.5. Determination of albumin <strong>and</strong> total proteins: Albumin <strong>and</strong> total proteins concentrations weremeasured using the spectrophotometer (Spectronic 601)at wavelength 628 nm. <strong>and</strong> 545 nm, respectively.Albumin was determined using bromocresol green (BCG)at pH 4.2 as described by Gowenlock (1988) .Determination of total protein was done by Biuretreaction as described in Gowenlock (1988).Calculations:Albumin <strong>and</strong> Total protein were calculated in thefollowing sequences:Albumin (g/l) = Absorbance of sample x 50Absorbance of st<strong>and</strong>ard50 = Concentration of bovine Albumin (g/l) of tilest<strong>and</strong>ard.Total Protein ( / I) = Absrobance of sample x lOOg Absorbance of st<strong>and</strong>ar¢]100 = Concentration of bovine albumin ~ng/l of thest<strong>and</strong>ard.. , 1 '" .

50 4.2.2.6: Determ of Serum Osmolal :­Serum osmolality was determined us vapourpressure osmometer 5100C from Wescor, USA. Calof Wescor osmometer was done us the st<strong>and</strong>ards A(290mmol/kg) <strong>and</strong> B(1000 mmol/kg) (from Wescor) asdescribed by the Wescor Manual (1983). In Wescorosmometer, an 8 microliter sample of the serum wasonto a small, solute-free paper disc, whichwas then inserted a chamber <strong>and</strong> sealed.A sensitive thermocouple hygrometer was incorporatedi I within the chamber. Thsensor on the bas of a thermalenergy balancing principle to measure the dewntwithinThe values obtained from Wescor Osmometer wered ly mmol/Kg.. \

51 4.3. Results:of the gazelle for 8 <strong>and</strong> 3consecut in <strong>and</strong> summerly,showed fol results:4.3.1 Haematology4.3.1.1 Red Cells (RBCs) <strong>and</strong> white B Cells(WBCs) :RBCs count from the normal of 13.9 ±0.59 x 1 /1 to 15.20± 0.60 x 10 12 /1 in all testedanimals that had been for 8 in winter.After rehydration the count decreased to a level of10% of the normal count two hours before dehydration.with 24 hours a count returnedto its normal level Fig(4).are highlysignificant (0.005 ,F=3.45).Significant (P sO.05 F=3. 22) werealso obtathree consecutles weresummer .forRBCs count rosefrom 12.38± 0.93X10 12 /l to 15.5±O.57 X10 12 /l with anincrease range of 2 . After rehydration the countdecreased to a level of 10% of1 count 2 hbefore 24 h after ion thecount returned to normal level .5).WBCs count were significant increased following. 05 , F=2 • 4 8 ) as rosefrom the normal level 3.95± 0.4 /1 to 5.1 ±

52 17 ----------- -----,- ---------------­Hydration Dehydration Rehydration16 -..(:,:s~ 15II)()~ 14 -13 -o 48 96 144 192 240 288 290 312HoursFig (4) Variation In mean of RBCs counts of gazelles during the experiment In winter.18HydrationDehydrationRehydration16 -..(:,:sVI()~ 14~ 12 -10 -8 ~~ ___~______L-__~______L_____~_____L___~______ ~____ ~__ ~o 48 96 144 168 170 192HoursFig (5) Variation In mean of RBCs count of gazelles during the experiment In summer.

53 1.35 x 10 9 /1 (29%). Within 24 hours of rehydration allanimals regained <strong>their</strong> previous countas beforedehydration (Fig.6).In the summer, dehydration of the gazelles forthree consecutive days resulted in asignificantincrease (PsO.05, F= 3.60) in the count of WBCs from4.11±0.90x10 9 /1 to 5.63±1.34X10 9 /1 (40%).Two hoursafter rehydration, a decrease of 4%in the WBCs countwas recorded, but within 24 h after rehydration thecounts of all tested animals returned to normal(Fig.7) .Comparison of the winter results with the summerones showed no significant difference (P~0.413,F=0.68) for RBCs counts in all stages of theexperiment (hydration, dehydration <strong>and</strong> rehydration).A similar situation was also obtained in the case ofWBCs counts, as the results of winter <strong>and</strong> summer wereinsignificantly different (P~0.265,F=1.27).4.3.1.2. Haemoglobin (Hb).Dehydration of the Idmi gazelles for -- 8consecutive days in winter, followed by rehydrationfor 24 h showed significant differences (P~0.016,F=2.66) in the blood Hb concentration. There was agradual increase in the Hb level concentration from174.5±8.7 gil to 190±4.8 gil (9%). Within 24 h of

546Hydration Dehydration Rehydrat ion7-... -- 0.-­enUCO~65432o 48 96 144 192 240 268 290 312HoursFig (6) Variation In mean of WBCs counts of gazelles during the experiment In winter.8 ,--------------------------------,---------------------,-----------------,HydrationDehydrationRehydrati on..-..o,sS

55 rehydration, the Hb level decreased to 170.6±10.6,Fig (8).Dehydration of the animals for 3consecutivesummer days followed by rehydration for 24 h resultedin a highly significant increase (P~0.005,F= 5.62) inthe level of blood Hb. The Hb level increased from164.3±9.7 gil upto 192.5±10.6 gil (15-21%). within 24hof rehydration the Hb level decreased to 161.5±16.0gil, (Fig.9). statistical analyses of the data of Hbconcentration of the winter results in comparison withthose of the summer ones showed no significantdifference (P~0.720,F =0.13) in all the three stagesof the experiment (hydration, dehydration <strong>and</strong> rehydration).4.3.1.3. Packed Cell Volume (PCV):Dehydration of the gazelles during winterresulted in a highly significant increase(P~0.005,f=3.63) in PCV. PCV increased from 51±1.3%to 55.8±2.0% with a percentage increase of 9%.24 hafter rehydration, PCV decreased to 49.2±2.2 %(Fig.l0).A highly significant increase (P~O.OOl,F=6.21)was also observed during summer. The PCVincreasedfrom 48.8±3.1 to 55.3 ±3.4 (13.3%) afterdehydration. On rehydration the PCV decreased, thusallowing the return to the normal level of 48.5±3.8%/

56 Hydration Dehydration Rehydration200 190 180 170 190 o 49 96 144 192 240 288 290 312 HoursFig (8) Variation In mGan of Hb ooncentratlon during the Gxporlment In wlntQr.HydrationDehydrAtionnohyurllilon200 --190 .­180 -170 180 o 48 96 144 198 170 192 Houre(9) Variation In mean of Hb concontration during the ...experiment In Bummer.c.

57 HydrationDehydrationRehydrallon5654~> 52oa..5048-o 48 96 144 192 240 288 290 312HOUfSFig (10) Variation In mean of PCV of gazelles during the experiment In winter.HydrationDehydrationRehydration54 -> 52 -oa.50 -4846 ~~______~______~____ -L______~____ ~______ ~____~______~____~__-Jo 48 96 144 168 170 192HoursFig (11) VAriation In mean of PCV of tho In ltlummer.

58before dehydration (Fig.11).Comparison of the winter results with those of thesummer ones did not show any significant differences(P~O.73,F=O.ll) in the PCV values in all stages ofthe experiment (hydration, dehydration <strong>and</strong> rehydration)•4.3.2: Serum Constituents:4.3.2.1 Serum Sodium (Na+)Dehydration during winter did not show asignificant difference (P~O.103,F=1.77) in the serumNa+. Serum Na+ gradually increased from 137. 2±4.1mmol/ I to 155. 2±4 . 0 mmol/ I - a 13.1% increase. Onrehydration a slight decrease was noticed within 2 hof rehydration (5.4%), but within 24 h the levelsreturned to normal (Fig.12).Dehydration of the animals in summer, caused ahighly significant increase (P50.001, F=6.97) in theserum Na+ concentration. The increment was about 19%,from a concentration of 141.8±3.5 mmol/l to 168.5±11mmol/l.On rehydration a slight (8%) decrease was noticedin the serum Na+ concentration after 2 h, but within24 h the level returned to normal (Fig.13).Comparison of the winter results with the summerresults showed a highly significant increa~e(P50.001,F=25.8) in Na+ concentrations during the, s,ummer./ The" i!;"'i'• t ,_ \ ,

59 165-HydrallonDehydra!lonRe hydra!ion-155:::::0E.s+ 145Z'"135125L-~__~____L­ __-L__~____~__~__~~__~__~____L­ __-L__~____~__~~o 48 96 144 192 240 288 290 312HoursFIg (12) VarIation In mean of serum Na+ of gazelles during the experiment In winter.180 .--------------------------------r--------------------r---------------~Hydra!lonDehydrallonAohydra!lon170 r-------------------------------~--------------------r---------------~-160:;:.oEg 160+z '"140 -130 -120 L-~______-L______L_____ ~ ______~____ ~ ______~____~L-____ ~ ______~~o 4896 144 - 168 170 192HoursFig (13) Variation In mean of serumNa+ of gazellos during the experiment In summer.. ,' I.'I)':!' jl~ '\i ,I. \ ' \" '.:'.I ~ ; ;.: , '~ .. ..

60 level of Na +concentration was 155. 2±4 . 0 mmol/ 1 inwinter, compared to the summer level that reached168.5±11 mmol/l during dehydration session, anincrease of 9%.4.3.2.2: Serum Potassium (K+)Gazelle's dehydration during winter days revealedan insignificant difference (P~O. 082, F=1. 88)in theserum K+(Fig. 14). Also, in the summer experiment,there was no significant difference (P~0.177,F=I.69)due to dehydration (Fig.15). Comparison of the winterresults with the Bummer ones revealed a highlysignificant (P~0.001, F = 31.12) increase as thesummer concentrations were higher than the winter onesby 12%, 35% <strong>and</strong> 20%in all the three stages of theexperiment (hydration, dehydration <strong>and</strong> rehydration) .4.3.3.3: Serum Chloride (Cl-).Dehydration during winter, followed by rehydrationdid not reveal any significant difference(P:50.114, F=1. 73) in the serum CI- concentration(Fig.16). Contrary to this in summer, when theseanimals were dehydrated the9 rehydrated, asignificant increase in the CI- concentration(P:50.005, F=5.68) was noticed. The serum Cl~increasedfrom 105.1±4.0 mmol/l to 115.8±3.6 mmol/l, a 10%i I:increase. The concentration returned to normal as, : :: i

L-__~____~______~______~______~______~______~______L_____~L_____~__~617Hydratio n Dehydration Rehydration6-~5oEE~+~43o 4696 144 192 240 266 290 312HoursFig (14) Variation In mean of serum K+ of gazelles during the experlmont In wlntor.6 .------------------------------,,--------------------r----------------,Hydration Dehydration Rehydration7-s­ oEg~6+~543o 46 96 144 166 170 192Hoursi IFig (15) Variation In mean of serum K+ of gazolles during the experiment In summer.:,..

62 before dehydration within 24 h of rehydration(Fig.I7).Comparison of the winter results with those of thesummer ones revealed that serum Cl- concentrationvaried significantly (P:$0.001, F=48. 27) . Theconcentration of Cl-increased gradually in winterduring dehydration to a maximum within 6 days ofdehydration, then reversed to a slight decrease by theend of the dehydration process. In summer, serum Clconcentrationcontinued increasing until the end ofthe dehydration process (Fig.16,17) .4.3.2.4: Serum osmolality (SO):Dehydration of the Idmi gazelles during winterdays, followed by rehydration revealed a significantincrease (P:$O.OI, F=2.81) in the serum osmolality. Theserum osmolality increased from 292.3±1.85 mOsm/Kg to350±4.82 mOsm/Kg, an increment of 20%. A decrease of5% was noticed within 2 h of rehydration, <strong>and</strong> thisdecrease continued until it reached normal levels(304±7.4) within 24 h of rehydration (Fig.i8).Dehydration of the animals during summer followedby rehydration revealed a highly significa~tincrease(P:$O.OOI, F=8.13) in the SO as it incr¢ased from302.9±5.7 mOsm/Kg to 354.5±6.8 mOsm/Kg, an lncrease of17%. within 2 h of rehydration the SO decre~sed by 5%I ' ,' I J i .' ~<strong>and</strong> the decrease continued till the init~~~ ~ormal, t· ~ I )~ i'l~ ", : ..$,

63 135 r--------------------,--------------------------------~----_r----------_.Hydralion Dehydration Rehydration130 -125o E 120Eu115110105 L-~__~____~__ ~____~__ ~__ __~___L__ ~____ ~__~____~__~____~__~~o 48 96 144 192 240 288 290 312HoursFig (16) Variation In mean of serum CI- of gazelles during the experiment In winter.\125HydrationDehydrationRehydration120115oE 110E~10510095o 48 96 144 168 170 192HoursFig (17) Variation In mean of serum CI- of gazelles during the experiment In summer..,< I ;," 3 j:I ,i : ~ . ~~: " ., "! !' ", ' .

64 __~____L___~___L___J____~__~___L__~____~__~__~__~~' . I370- Hydration Dehydration Rehydrati on0; 350~---0Ẹ ,0 330E-~--co3100Ẹ0,E 290:::J...CD(/)270- -250 L-l-__-Lo 48 96 144 192 240 288 290 312HoursFig (18) Variation In mean of serum osmolality of gazelles during the experiment In winter.370Hydrallon Dehydration Rehydration-CI~ 350 -oE1/1oE-330~~oE~ 310 -E::3...41(/)290 -270 L-~______~______ L- ____~______~____ ~__ ____~____-L~____~____~__~o 48 96 144 -166; : 170 192Hours,[,I; ...11,,:Fig (19) Variation In mean of serum osmolality of gazelles during the experiment In summer.• ,0; ". :< ' .: .!

65 level (303.5±4.6) was attained after 24 h ( .19) .son of the results those of thesummer revealed a highly signif difference(PSO. DOl, F=l1. 73) the three ofthe experiment (hydration, dehydration rehydration),( .18,19).4.3.2.5: Serum Glucose:of the lesrevealed no significant difference (P~O.238,F=1.38)in the serum glucose concentration (Fig.20).A s lar s was anwerefor 3 summer days, as on rehydratthere was no significant difference ( .359, F=1. 2)serum ( .21) .Compar of the winter results summer onesrevea no significant difference . 086 I F= 3 . 05 )in the serum glucose.4.3.2.6: Blood Urea (BUN) :I'lowed byreveal a significant increase (Pso. " F=2. 38) in! .the BUN concentration. BUN concentratlon' edfrom 13.76±2.66 to 31.8±3.23 mmol!l,of131%. with 24 h iondecreased to 16.11±2.36 mmol!l (.22) •Also summer when the gazelles <strong>and</strong>

669r-------------------~-------------------------------------r----------~HydralionDehydrallonRehyd ralion8CD0)og6t!'-5- ­4 L-~__-L__~____~__~__~__ ~____~__J­__~__~____~__-L__~____~o 48 96 144 192 240 288 290 312HoursFig (20) Variation In mean of serum glucose of gazelles during the experiment In winter.9 ~-------------------------------r---------------------r-----------------.HydrallonDehydrationRehydration8 -~7oE.s6Q)eno::JCJse.0 _ L" la i. ... " 'J'.: :. 1'.1 '" ·'i ! I'!'' 1::"" . ~ ~43 L-~______~__ ____ ~____~______~____~____~~____~______~__ __-L~o 48 96 144 ,. 168 170 192HoursFig (21) Variation In mean of serum glucose of gazelles during the experiment In summer.'.'

67 40Hydration Dehydrallon Rehydration3530:g 25EgZ:::l 20CO151050 48 96 144 192 240 288 290 312Hours Fig (22) Variation In mean of BUN of gazelles during the experiment In winter, 19 ,-----------------------------,-------------------,----------------,Hydration Dehydration Rehydration17151311 -9 -­o 48 96 144 168 170 192HoursFig (23) Variation In mean of BUN of gazeiles during theIn summer.

68 rehydrated, that revealed a highly significantincrease (P~0.005,F=4.56) in the BUN concentration.BUN increased from a level of 9.73±0.54 mmolll to16.17±2.38 mmolll, an increase of 66%.Rehydration for24 h lead to a decrease in the BUN concentration downto a level of 11. 91±1. 77 mmoll l, a decrease of 26%(Fig.23).comparison of the winter results with those of summerrevealed a highly significant difference (P~O. 001,F=21. 23) in the BUN concentration. The winter BUNconcentration was higher than the summer one (41.4%)during hydration, but at the end of the dehydrationsession the increment of BUNlevel rose till itreached 79% of the summer results. After 24 h ofrehydration the winter BUN concentration was alsohigher than the summer level by 35.3%4.3.2.7: Serum Total Protein (TP):Dehydration of the gazelles in winter, followedby rehydration revealed a highly significant increase(P~O.OOl, F=5.15) in the TP level. The TP levelincreased from6.09±O.56 gil to 6.4±O.64 gil, anincrease of 5%. Within 24 h of rehydration the leveldecreased to 5.08±0.52 gil, a decrease of 20.6%,(Fig.24).Dehydration of the animals in summerrevealed a significant increase (PsO. 01 i'F=4 . 1) in. '.. j. ,!.

69 7 r---------------------~------------------------------------r_--------_.HydrationDehydrationRehydration6.5 -6 5.55 ~ __-,-I__-,--- ~.~ L..I_---'-__'--_ ~..l-I_---'__'--_-'-__ ..L.....__--'-__.L..........-... o 46 96 144 192 240 288 290 312 Hours Fig (24) Variation In mean of serum total protein of gazelles during the experiment In winter.7.5 I----------------------------~-----------------~-------------~76.565.5o 48 96 144 168 170 192 Hours (25) Variation In mean 01 total protein of gazelles during the experiment In summer.

70 the TP concentration, as the level increased from aninitial normal value of 5.9±0.53 gil to a value of7.2±0.85 gil, an increase of 22%. The TP level droppedto 5.6±0.88 gil after 24 h of rehydration, a drop of22% (Fig.25).comparison of the winter results with those ofthe summer, revealed a highly significant difference(P~0.001,F=27.81) in the TP level. The summer TPlevel was higherthan the winter level during the<strong>water</strong> <strong>deprivation</strong> <strong>and</strong> rehydration sessions by 12.5%<strong>and</strong> 9%, respectively, whilst the levels in thehydration were nearly the same.4.3.2.8: Serum Albumin:Dehydration of the gazelles during winter,.. -" '. : " ,;.' ~ . :,... ( ···,~ :: ,,.~~~~~}.:!:.j.;f, ·

71 Dehydralion-­ 0.......Eg£:E::l..a;;:(490440390o 48 96 144 192 240 288 290 312Hours Fig (26) Variation In mean of serum albumin of gazelles during the experiment In winter. 590 Hydration Dehydration Rehydration570550530£:'e.& 510::(490470 -4500 48 96 144 168 170 192HoursFig (27) Variation In mGsn of serum albumin of gazelles during the experiment In aummQf.

72 albumin. The serum a~~uHl~from a level of519.4±18.5 ~mol/l to a value of 561.6±18.8 ~mol/l, an8% within only 2 days. the end of thesession adown to 547.1±21.5 ~mol/lwas not Rehydration of the animals for 24 hfurther reduced the serum albumin level down to468.7±16.9 /1, a ion of 17% (F .27).ison of the winter results with those ofthe summer revealed a highly signiffference(P:::;O.OOl, F=109.81) the serum albumin concentration.The summer serum albumin levels wereh than the levels the ofthe experiment (hydration, dehydration, <strong>and</strong> rehydration)by a of 12%, 17% <strong>and</strong> 2respectively.

. 73gazelle (G. 1a) 8having an access to <strong>water</strong> in winter. But in summer theI survived for only 3 days whenof <strong>water</strong>. This endurance of thelonger dehydration periodwasgazelle forthan in summercould be attrto the <strong>effect</strong> of weather(e. g. on the1 inthe body of these animals. Theofwas higher summer than (see3) as a signif lity hadtheof many bloodthat cou be i as :­4.4.1 RBCs <strong>and</strong> WBCs:­The RBCs <strong>and</strong> WBCs counts had increasedwinterby 9% 29%, I during ion, thenreturned to <strong>their</strong> normal values after rehydration. Insummer, the RBCs WBCs counts had by a25% <strong>and</strong> 40%,, <strong>and</strong> then returned to thenormal va before . Ana of theseresults reveahada high s on the numbers of RBCs <strong>and</strong>WBCs.in the numbers of RBCs <strong>and</strong> WBCsdue to summer could beias a resufleads todecrease in the

74 (Ghobr I, 1967). It could also be buted to thedecrease in plasma volume (Macfarlane et al., 1961 <strong>and</strong>Mohammed et ala 1988). The lossvolumedue to loss ion, asby the increase of the body( 1972), of <strong>water</strong> withfaeces (Ghobr I <strong>and</strong> Cloudsley-Thompson, 1966,1 1967 <strong>and</strong> 1970b <strong>and</strong> Taylor 1972).As the rate ofcorrelated withthe<strong>and</strong> the animal's temperature (Ghobrial,1970b; 1972) I the reasons the slowin the numbers of RBCs <strong>and</strong> WBCs, coube wellunderstood add to blood parametersduring ion to summer.4.4.2:- Haemoglobin (Hb):Dehydration of the gazelles in winter <strong>and</strong> summerled to an the Hb level a 9% <strong>and</strong> 17.2%,ion, the levels returned tonormal <strong>and</strong> the were s f <strong>and</strong>highly sficant in summer. The reason behind theHb concentration could be due to thedecreaselular fluid thathaemoconcentration <strong>and</strong> then annumberof RBCs <strong>and</strong> Hb concentration.It could also be due tothe decrease cel <strong>water</strong> content of the RBCsthat led to the accumulation of Hb level. These

75 results are in agreement with those of Ghobrial <strong>and</strong>Cloudsley-Thompson (1966) on the Sudanese Afri gazelle(G.dorcas) ,as the Hb level increased by 53% when theanimal was dehydrated 5 days in summer, <strong>and</strong> those ofMacFarlane et al. (1961) on merino sheep as the Hblevel increased by 33% when the animal was deprived of<strong>water</strong> for 4 days in summer.4.4.3:- Packed cell volume (PCV):­Dehydration of the gazelles in winter <strong>and</strong> summerresulted in an increase in the level of the PCV by 9%<strong>and</strong> 13.3 %, respectively. On rehydration the levelsreturned to normal. This situation could beinterpreted as an <strong>effect</strong> of haemoconcentration thatfollowed the decrease in plasma volume <strong>and</strong> all bodyfluids. These results are in agreement with those ofGhobrial <strong>and</strong> Cloudsley-Thompson (1966) on the SudaneseAfri gazelle as the PCV increased by 19% when thegazelle was dehydrated for 5 days in summer, inaddition to the results of Gray et al. (1979)onhorses. Similar results were also attained byMacFarlane et al. (1961) on merino sheep, however,<strong>their</strong> results showed an increase of 28% in the pev ofthe dehydrated animals for a period of 4 days duringsummer.

76 4.4.4:- Serum sodium (Na+):Dehydration of the gazelles in winter <strong>and</strong> summerresulted in an increase of the serum Na+ by 13.1% <strong>and</strong>19%, respectively. On rehydration the levels returnedto normal.These results were not significant inwinter, but in summer the results were highlysignificant. The increase in the serum Na+concentrations could be attributed to the loss in theplasma volume <strong>and</strong> extracellular body fluids (Mohammedet al 1988). This could be an <strong>effect</strong> of thealdosterone as it stimulates the kidneys to increasethe rate of reabsorption of Na+chapter 5. These results are in(Sonbol, 1988), seeagreement with thefindin'gs ; '~' Of'~iMoha:mme""d:~#e'£e~a~';~~rf988y"f'"on "" the SudaneseAfri (23%) during summer dehydration. Similar resultswere also obtained by Musa (1978) on sheep (18%) <strong>and</strong>Camels (15%).4.4.5:- Serum potassium (K+):Gazelle's dehydration in winter <strong>and</strong> in summerrevealed no significant difference in theconcentration of serum K+. These results were similarto those obtained by Gary et ale (1979)on horses.Musa (1978) reported that there was no appreciableincrease in the serum K+ level of sheep, but there wasa 3% increase for goats <strong>and</strong> a 4% increase in camels.

77 ison of the winter results with those ofthe summer results revea an the summerserum K+ by 12.35 <strong>and</strong> 20% hydration,Irespectively. The summerto therate of evaporation which leads to atheloss inplasma volume <strong>and</strong> extracellular f (Mohamed,1986) •4.4.6:­ Serum chloride ( ) :of the in <strong>and</strong> summerrevealed an increase in the levels of serumIbutthis level was signif summer (10%). Thincrease was to the loss of theextracelluar ion. S larresults were ined by Mohamed et al. (1988) butthe results showed an 18% of the level.The drop of the end ofto <strong>water</strong>c ).ion decrease of (the source of4.4.7:- Serum lity:During two periods <strong>and</strong> summerion the level of serum osmolality wasincreased by 20% <strong>and</strong> 17%, respectively. within 24 hlevereturned to normal. This

78 increuse could be attributed to the decrease in boththe plasma volume <strong>and</strong> the extracelluar fluids, whichhave led to an increase in the Na+ concentration whichis correlated directly proportional to osmolality(Gary et al., 1979). Osmolality is also correlated tothe increase of electrolytes that had increased atdifferent proportions according to dehydration. Theincrease in SOcould be a function of antidiuretichormone (ADH) , as it increases in serum with theincrease ofosmolality (Robertson et al 1976). Itcould also be a function of aldosterone, as itstimulates the kidneys to increase the rate ofreabsorption of Na+ (Sonbol, 1988), which leads to anincrease in serum osmolality (Gary et al., 1979).These results agree with those of Choshniak <strong>and</strong>Shkolnik (1977) on the black Bedouin goat. Little etal. (1976) working on Cattle reported that osmolalitycould be used as a good <strong>and</strong> sensitive parameter forshortage of <strong>water</strong> (dehydration). Maltz et al. (1984)obtained similar results by working on the blackBedouin goat, but adifference was noticed in theslowness of regaining normal serum osmolality afterrehydration which was due to the slow absorption of<strong>water</strong> in the goat rumen. These results agree withthose of Abdelatif <strong>and</strong> Ahmed (1994) on the desertsheep, as the increment was 10% when sheep dehydratedfor 3 days in summer.

794.4.8:- Serum glucose :­During the winter <strong>and</strong> summerdehydration ofgazelles, there wasno significant increase in thelevel of serum glucose.Comparison of the winter levels with the summer levelsrevealed no significant differences. These resultsshowed that the gazelles were able to keep <strong>their</strong> serumglucose balanced <strong>and</strong> the narrow range of differencecould be due to the decrease in the plasma volume.These results differ from those obtained by Musa(1978) who stated that serum glucose of sheep <strong>and</strong>goats increased by 27% <strong>and</strong> 24%, respectively, <strong>and</strong> wassignificantly different in the dehydrated camels. Theresults were also different from those obtained byMohamed (1986) who reported that serum glucosedecreased by 34.4% in the dehydrated Sudanese Afrigazelle (10 days in summer), <strong>and</strong> he attributed this tothe low food intake with the continuation ofdehydration.4.4.9:- Blood urea nitrogen (BUN):Dehydration of the gazelles during winter <strong>and</strong>summer resulted in an increase in the level of BUN by131% <strong>and</strong> 66%, respectively. On rehydration the levelof BUN decreased by 49% in winter <strong>and</strong> 40% in summer.This increment could be due to the loss in

80 plasma volume extracel flu. It isthat the reductionplasma volume had reduced therate of fi of <strong>and</strong> the oliguria tendedtourea absorption leading to high blood ureaconcentration (Mohamed, 1986). lar results were1 <strong>and</strong> (1966)the Sudanesegazelle (125%), <strong>and</strong> by MacFarlane etale (1961) for the mer sheep, who attr thehigh level (325%) in BUN to renal failure thatfollowed dehydration. These resu are also s ito the results of Abdel if <strong>and</strong> Ahmed (1994) on, as increment of the urea was36% when the 1 dehydrated for 3 summer.4.4.10:- Serum total (TP) :during<strong>and</strong>summer resulin an increase in the level of TP by5% <strong>and</strong> 22%, of1 the summer level revealed an increase of12.5% <strong>water</strong> <strong>deprivation</strong> summer. wasattributed the decrease in the <strong>and</strong>the extracelluar flu . S lar wereby Gary et ale (1979) on horses (14%), <strong>and</strong> those ofMacFarlane (1961) on <strong>and</strong> f <strong>and</strong>Ahmed (1994) on desert(7%) •

81 4.4.11:- Serum albumin:Dehydration during winter <strong>and</strong> summer resulted inan increase in the serum albumin by 3% <strong>and</strong> 8%,respectively. This was followed by a decrease of 20%<strong>and</strong> 14%, respectively on rehydration. This situationcould be interpreted in terms of the decrease in theresults agree with those obtained by Mohammed et ale(1988) as serum albumin increased by 18% when theanimal was dehydrated for 10 days in summer.Theincrease in albumin level could be an adaptation ofthe gazelle to increase the osmotic pressure of theblood. By doing so, the vascular spaces would gainmore <strong>water</strong> from the extra <strong>and</strong> intracellular fluid, <strong>and</strong>thereby maintaining the plasma volume within thetolerable range (Wilson, 1984). '!'he decrease in thoserum protein concentration associated with thecontinuation of dehydration could be attributed to thelow intake of food (chapter 6).Comparison of the winter results with the summerresults revealed an increase in the levels of thesummer albumin in all the stages of the experiment(hydration, dehydration <strong>and</strong> rehydration) by 12%, 20%,<strong>and</strong> 26%,respectively. This could be due to thegreater rate of decrease in the summer plasma volumeresulting from increased evaporation.

EFFECT OF TEMPERA'TURE AND WATER DEPRIVATION ON SOME URINE CONSTITUENTS

83 5.1. Introduction:­There are no previous records on the <strong>effect</strong> ofheat <strong>and</strong> dehydration on the urine constituents of theIdmi gazelle (G. gazella) or any other Arabiangazelle. However, studies have been done on SudaneseAfri gazelle, other African gazelles <strong>and</strong> other groupsof mammals. Ghobrial <strong>and</strong> Cloudsley-Thompson (1966)repOL" tell thn t the volume of the urine o[ thedehydrated Afri gazelles decreased to 1/8th (from 200­700 ml to 30-80 ml) in comparison with the normalvolume.Taylor et ale (1969) found that the <strong>water</strong> lostthrough urination was not affected by dehydration ofAfrican antelopes. They also reported that the mainfactors controlling the loss of <strong>water</strong> throughurination are electrolytes <strong>and</strong>nitrogen in food.Ghobrial (1970b)mentioned that there were severalfactors controlling the volume <strong>and</strong> concentration ofthe urine in the Afri gazelle, most important of thesewere the volume of the <strong>water</strong> taken, quantity <strong>and</strong>quality of food, volume of <strong>water</strong> lost throughrespiration <strong>and</strong> thermoregulation, the surroundingstemperature <strong>and</strong> relative humidity. Louw<strong>and</strong> Seely(1982) reported that the animals possessing the loopof Henle in the kidney tubules are the ones that wereable to produce concentrated urine. Theyadded'thatthe more the number of loops of Hen!e the better was-­

84 the abil of the kidney to concentrate the <strong>and</strong>hence retain <strong>water</strong>. Grenot (1992) reported thatwas an apparent relationship between the abilofk ney to concentrate urine <strong>and</strong> ar ofhabitat. He addedof the level ofurine flow accomplished two methods. firstone regu when the ltrate enterthe nephrones. The second is distributing the amountof the fi absorbed in col ducts. Healso ment that an evolution had occurred theloop of Henle1 of these capabil of thek in <strong>water</strong> <strong>and</strong> hence urineion. This situation is in agreement with theof Wilson (1984) who ment that the<strong>and</strong> funct the kidney are 1for <strong>water</strong> retention, <strong>and</strong> theimprove the output <strong>and</strong> urineof Henle's. Thealso controls body <strong>water</strong> by urconcentrating its rate of flow. The urnot only useful in <strong>water</strong>a anima to<strong>and</strong> <strong>water</strong>in high levels of salt.Ghobrial (1974)reduced the volume ofzelles3-4 times when they weredehydrated,in addition to that they concentrated<strong>their</strong> ur . She found dehydration

85 resulted in an increase in the urine urea by 70%, <strong>and</strong>the K+ (Potassium ion) by 52%, contrary to theconcentration of Na+ <strong>and</strong> Cl- which were reduced to 43%<strong>and</strong> 26%, respectively. Ghobrial (1976) reported thatthe Afri gazelles that tooksea <strong>water</strong> producedconcentrated urine exceeds the concentration of theurine produced by gazelles that took soft <strong>water</strong> by300% (3100 mOsmolJl), <strong>and</strong> more than the dehydratedones by 16% (500 mOsmlJl). Mohammed et al. (1988)stated that the volume of urine of the 10daysdehydrated Sudanese Afri gazelles was reduced by 66%.On rehydration the volume returned to normal on thesecond day. These results are similar to those ofJhala et al. (1992) who reported that 3 daysdehydration of the black-buck produced 50% reductionin the urine flow rate. They also mentioned that thisprocess was accompanied by a 25 times increment in thetotal urea excreted in the urine, contrary to this wasthe reduction in the Na+ <strong>and</strong> K+ concentrations by 82%<strong>and</strong> 47%, respectively, in the dehydrated animalsurine.MacFarlane et al. (1961) working on the merinosheep found out that the urine volume was continuouslyreduced by dehydration. This situation was accompaniedby a remarkable reduction in the Na+ <strong>and</strong> K+concentration.On rehydration the levels returned tonormal.

86 et . (1962) that urea excretin cattle was basicallyon the crude protecontent of the food taken. They alsothatthere was a d proportional re betweencrude of the <strong>and</strong> ion of theexcreted urea ncontrary tothe workof Brown (1972) onwhere they found that the urine volumewhilst the urea nitrogen concentration has<strong>and</strong> the same s also forosmolality in comparison with <strong>water</strong>ed sheep. Little et(1976) found that osmolal of thedairy cows s <strong>water</strong><strong>deprivation</strong>, but the Na+ <strong>and</strong> K+concentrations <strong>and</strong>urine volume d s f with <strong>water</strong>depr ion. Choshniak et al. (1984) found theurvolume of the dehydrated Bedouin goat is reducedby 50%, <strong>and</strong> after 4 levelreturned to normal. also not a decrease inofNa+ <strong>and</strong>fourafter rehydration by 47% <strong>and</strong> 34%,ly,no change occurred with theof K+ <strong>and</strong> urea.The ect this the investigationwas to<strong>and</strong>onof

87 Na+, K+, cl-, urea in urine <strong>and</strong> urine osmolality.These are considered to the parameters of theadaptations of the Idmi gazelle for preserving <strong>water</strong><strong>and</strong> resisting thirst.5.2 Materials <strong>and</strong> Methods:­The work was done in two main parts. The firstpart was done in the field as the urine samples werecollected <strong>and</strong> the urine volume was measured.Thesecond part was done in the laboratory.Urine samples/24h were collected, during allstages of the experiment (Hydration, dehydration <strong>and</strong>rehydration) in winter <strong>and</strong> summer, using the metaboliccage. The samples were collected in the graduatedbottle that had been placed under the lower part ofthe cage (Fig.1).5.2.1 Urine Volume:­The urine volume was measured using the lowerlevel of the metabolic cage as was described inchapter 2. The loss of the urine due to evaporationwas assessed using the sixth cage which had no gazelleinside.A measured volume of urine was poured intothe cage (over the third level) <strong>and</strong> left till itaccumulates into the bottle.After 24 h the bottlecontent was measured using a measuring cylinder.

88 Calculations:­Total urine loss=the initial urine volume-bottlecontent volume.The urine volume = bottle content volume + total urineloss.5.2.2 Determination of Urine Sodium (Na+) <strong>and</strong> UrinePotassium (K+):­The Na+ <strong>and</strong> K+ levels were determined by the useof Na/K Analyzer from Orion (Orion 1020) using the ionselective electrode system (Chapter 4). Urine sampleswere diluted with Mg(C 2 H 3 0 2 )2 in ratio of 1/10 (1:9).The values of Na+ <strong>and</strong> K+ were given as mmol/l directly.5.2.3 Determination of Urine Chloride (Cl-):­The urine Cl- level was determined by the use ofa Chlorofix Kit (A. Menarini Divisione Diagnostici,Italy), using the spectrophotometer (From Spectronic601) as described in Chapter 4.5.2.4. Determination of Urine Urea:­The urine urea was measured by the use of 'Urea­Kit S 180' from bioMerueux using urease-modifiedBerthelot Reaction, as had been described by Gowenlock(1988). The urine was diluted with distilled <strong>water</strong>(1/100) .

89 The values were obtained from thewhich readsreaction at 580 nm wavelength.Ca :­Urea (mmol/l) =-,__-,,-____-=~.-~--~ x 55 = Urea in (mmol/I) .5.2.5. ion of Ur Osmolality:­The osmolality was by the use oftheIPressure Osmometer 5100' from Wescor, USA.The calion of the Wescor Osmometer was done usthe st<strong>and</strong>ards A (290 8(1000 mmoll ) ashad been described by the Wescor Manual (1983).was mentwere diluted 1/10 I4. As thethe Wescor Osmometer vammol/kg were corrected byfactor 10 to convert the

90 5.3: Results:­Dehydration of the Idmi gazeduring<strong>and</strong> summer led to some in the volume <strong>and</strong>constituents.5.3.1. Urine volume:­A signif 0.01, F=2.55) wasnoticed in the urine volume dehydration of thegazelles for 8 a 24-h. The ur volume was reduced from 301 ±42ml/24 h to 171 ± 43 ml/24 h (a 43% decrease). Onion the was to 213 ± 16 24h - a 25% • 28).In summer , a icant decrease 0.001,F=7.75) was in thedehydration folby a 24 h rehydration. The urinevolume was reduced more than 1/6 (from 345 ± 125/24 h to 48 ± 11 ml/24 h) on ion, theurine volumeto 129 ± 52 ml/24 h (169%) Fig.(29) .A signi di 0.05, F=4.47) wasnot the summer, asthe urine volumesummer was more than that ofby 13%,whiwinter volumes were greater by 256% <strong>and</strong> 39% dur<strong>water</strong> ivat <strong>and</strong> ion,

91 400 - RehydrallonHydrationDehydration350-~ ~ ~ 300E­CI)E:::J 2500>CDc''::::> 200150100 L-~____ ~ ____ ~ __ ~ ____ ~ ____ ~ ____ L­__ ~ ____ ~ ____ ~ __ ~ ____ ~ ____ ~~24 48 72 96 120 144 168 192 216 240 264 288 312HoursFig (28) Variation In mean of urine volume of gazelles during the experiment In winter.500 -- -- -- ---- - -- - --- ----------,-----------­Hydration Dehydration Rehydration400 --~~N::::- 300E­CDE:::Jo>CI) 200 -c100o L-__ ~ ________-L________J_________ ________ ______ ________,~------~--~~24 48 72 96 120 144 166 192HoursFig (29) Variation In mean of urine volume of gazelles during the experiment In summer.

92 5.3.2. Urine Sodium (Na+):­Dehydration during winter followed by rehydrationshowed a significant increase (psO.05, F=2.07) in theconcentrations of the urine Na+.The level of Na+concentrations increased in the first five days from218.1 ±44.4 mmol/l to 283.2 ± 36.3 mmol/l (30%). Thendropped gradually to 135.8 ± 16.6 mmol/l (52%decrease) by the end of the dehydration session, <strong>and</strong>on rehydration the level of Na+increased until itreached 173 ± 21.4 mmol/l (Fig. 30).Dehydration during summer followed by rehydrationshowed a highly significant difference (PsO.001,F=4.86) in the urine Na+ concentration. The urine Na+decreased from 181 ± 27.4 mmol/l to 58.0 ± 17.5 mmol/lby the end of the dehydration session, <strong>and</strong> onrehydration the Na+ level rose to 95.8 ± 26.6 mmol/l(Fig.31).Comparison of the winter results with those ofthe summer revealed ahighly significant (psO.001,F=29.75) difference. The winter urine Na+concentrations were higher than those of summer in allparts of the experiment (hydration, <strong>water</strong> <strong>deprivation</strong><strong>and</strong> rehydration) by 17%, 58% <strong>and</strong> 45%, respectively.5.3.3 Urine potassium (K+):­Dehydration during winter followed by rehydrationrevealed a significant increase (psO.005, F~3.12)in

93 350 ,------------------,---------------------------------------,---------,Hydration Dehydration Rehydration300-- o::::- 250E!.+."Z 200150-100~~----~--~----~--~----~----~--~----~--~----~----~--~~24 48 72 98 120 144 148 192 218 240 264 288 312HoursFIg (30) VarIation In mean of urIne Na+ Of gazolles durIng the experIment In wlntor.260HydrationDehydrationRehydration210oE 160E~+1\1:z1106010 ~--~------~------~------~------~------~--------~------~------~~o 24 48 72 96 120 144 166 192HoursFIg (31) Variation In mean of urine Na+ of gazelle8 durIng the experIment In summer.

94 the urine K+ concentrations. The K+ concentrationsincreased gradually from 216.3 ± 61.9 romol/l to 321.6± 40.7 mmol/l (49% increase) on the fifth day !?_~dehydration. This was followed by a reduction in theK+ concentration until it reached 278.6 ± 50.6 mmol/l(13% decrease) by the end of dehydration session. Onrehydration for 24 h the levels of K+returned tonormal (Fig. 32) .Dehydration of the gazelles during summerfollowed by rehydration revealed a significantdifference (P~0.05,F=2.52)in the K+ concentrations.The K+ levels were reduced from 361.8 ± 37.9 mmol/l to302.5 ± 32.2 mmol/l (16%). The levels rose to 326 ±21.4 mmol/l after 24 h (Fig.33).Comparison of the winter results with those ofthe summer revealed a highly significant difference(P$O.OOl, F=66.95). Summer K+ concentrations werehigher than those of winter by 40% <strong>and</strong> 53% in twoparts of the experiment (hydration <strong>and</strong> rehydration).There were variations in the response to <strong>water</strong><strong>deprivation</strong>, the levels of K+ concentrations increasedby the onset winter dehydration which was followed bya decrease at the end of the session. The situation insummer revealed a gradual decrease from the beginningof the dehydration session up to the end.

95 400 iHydration Dehvdration Rehydration350300

96 5.3.4. Urine Chloride (Cl-):­Dehydration during winter followed by rehydrationrevealed no significant difference (P~0.110,F=1.70)in the concentrations of the urine Cl-(Fig.34). Thesame situation was obtained during summer dehydrationfollowed by rehydration,as there was no significantchange (P~0.162,F=1.65) in the urine Cl- (Fig.35).Comparison of the winter results with the summerones revealed a highly significant difference(P~O.OOl,F=17.06), as the winter dehydration urineconcentration was higher than the summerdehydration urine Cl­ concentration by 43%. On theother h<strong>and</strong> the Cl­ levels during hydration <strong>and</strong>rehydration were almost the same.5.3.5. Urine urea:­Dehydration during winter followed by rehydrationrevealed a highly significant difference (P~O. 001,F=3.84) in the concentrations of the urine urea, as anincrement from 1976 ± 306 mmol/l to 3233 ± 515 mmol/l(39%) was recorded. The levels returned to normalafter 24 h of rehydration (Fig. 36).Dehydration of the gazelles for 3 summer daysfollowed by 24 h rehydration also revealed a highlysignificant difference (PsO.005, F=3.82) in the urineurea concentration, as an increment from 3123 ± 493mmol/l to 5155 ± 79 mmol/l (65%) was recorded. The

97 550r------------------.~----·------------------------------------~------_.Hyd ration450 -350 (3 250 150 24 46 72 96 120 144 168 192 216 240 264 266 312 Hours Fig (34) Variation In mean of urine CI' of gazelles during the experiment In winter.DehydrationRehydration400. U300 -200 -o 24 48 72 96 120 144 168 192 Hours (35) Variation In mean of urlno CI' of gazolle8 during tho exporlment In Gummar,

98 4000 r-----------------~------------------------------------------~------~IIydrnliollDehydrationnehydrnllol3500­,....:::::.~ 3000gIIICD....::J~ 2500;:::>2000-1500~~----~--~----~--~----~----~--~----~----~--~----~--~~24 48 72 96 120 144 168 192 216 240 264 288 312HoureFig (36) Variation In mean of urine urea of gazelles during the experiment In winter.6 ~----------------------------------~--------------------~r----------.HydrationDehydrationRehydration,....5::::::.'0Ego 24 46 72 96 120 144 166 192HoureFig (37) Varlallon In mean of urine urea of gazelles during the experiment In summer.

99 levels returned to normal after 24 h rehydration(Fig . 37) .comparison of the winter results with the summerones revealed a highly significant difference(PSO.001, F=96.61) in the concentration of the urineurea, as the summer concentration was higher than thewinter ones in all the stages of the experiment(Hydration, <strong>water</strong> <strong>deprivation</strong>, <strong>and</strong> rehydration) by aratio of 58%, 60% <strong>and</strong> 62%, respectively.5.3.6. Urine osmolality (UO):­Dehydration during winter followed by rehydrationrevealed a highly significant increase (PsO.OOl,F=7.48) in the level of urine osmolality, as the UOlevel gradually increased from 2523 ± 590 mOsm/Kg to4493 ± 382 mOsm/Kg(78%) in the 6th day of dehydration,then the level decreased to3521 ± 216 mOsm/Kg(22%)by the end of the dehydration period. On rehydrationthe level of VO decreased to 3098 ± 194 mOsm/Kg, a 12%decrease (Fig.38).Dehydration of the gazelles during summerfollowed by rehydration revealed a highly significantdifference (psO.005, F=4.07) in the level of UO, as itincreased from 2401 ±337 mOsm/Kg to 3668 ±139 mOsm/kg(53%) .On rehydration the level decreased to 3185 ±231mOsm/kg ,a 13% decrease (Fig.39).

100 5.5 ,-----------------,-----------------------------------------r------,HydrationDehydrationRehydratior01~c : 4.5 :::Io.cI­~t:7I~E CII 3.5oSoECIIo~ 2.5 -a::;:)1.5 ~~____L____L____~__~____~____~__~____~__~____~____L-~_L~24 46 72 96 120 144 164 192 216 240 264 266 312HoursFig (36) Variation In mean of urine osmolality of gazelles during the experiment in winter.4200 -HydrationDehydrationRehydration3700~t:7I~~ 3200oSciE 2700In0QIC.;:::::> 2200-1700 -1200 ~~L-____~______~______~______~____~______~______~______L_~o 24 46 72 96 120 144 166 192HoursFig (39) Variation in mean of urine osmolality of gazelles during the experiment In summer.

101comparison of the winter results with those of thesummer showed a highly significant difference (psO.OOl,F=21.91) in the level of UOas the level in winterincreased gradually until it reached its highest levelon the 6th day, alevel that exceeded the highestsummer UO level by 23%. This wasdecrease in the level that was almostfollowed by asimilar to thesummer end of depY. ~lfa~iC?:t:'l ;. ; >~~~el. The levels before':' ...,.' .. ,..... .-: . ~ .. ~ ->;: ~ •.

102 5.4. Discussion:­Dehydration of the Idmi gazelles under winter <strong>and</strong>summer conditions lead to several significantvariations in urine volume <strong>and</strong> its composition.5.4.1. Urine volumeDehydration of the Idmi gazelles during winter<strong>and</strong> summer lead to a reduction of about 43% <strong>and</strong> 619%in the urine volume, respectively. On rehydration thelevel rose by 25% <strong>and</strong> 169%.The decrease in the urine volume is due to the<strong>deprivation</strong> of <strong>water</strong>. As reported by Gauthier-Pilters<strong>and</strong> Dagg (1981), it may be a function of high tubularreabsorption in the kidneys <strong>and</strong> its high sensitivityto the ADH. Ghobrial (1970b) <strong>and</strong> Taylor (1972) agreedwith the previous -,,.~\fn~~ .ngfi" j.: but they added that thisbecome more clear during summer as the ambienttemperature lead to greater loss of evaporative <strong>water</strong>from the body.Sonbol (1988)mentioned that the decrease of bodyfluids would increase the osmotic pressure . In suchconditionsOsmoreceptors become active , <strong>and</strong> thatwould stimulate the pituitary gl<strong>and</strong> to release ADH.This would affect the distal convoluted tubules <strong>and</strong>collecting tubules <strong>and</strong> encourage them to increase therate of <strong>water</strong> reabsorption. A decrease in the urinevolume may also be a function of the <strong>effect</strong>s of the

103aldosterone, as it stimulates the distal convolutedtubules to increase the rate of reabsorption of Na+.This would be followed by reabsorption of <strong>water</strong> <strong>and</strong>hence reducing urine volume. These results are inagreement with those obtained by Ghobrial (1974) onthe Sudanese Afri, as the urine volume decreased 3-4folds when the animals were dehydrated Similarresults were obtained on Afri gazelle by Mohammed eta1. (1988) as the urine volume decreased by 66% duringdehydration for 10 days, <strong>and</strong> on goats by Choshniak eta1. (1984) as the urine volume decreased by 50% .5.4.2 Urine Sodium (Na+):Dehydration during winter led to an increase inNa+ concentration of the urine by 30%, for the first5 days of dehydration. That was followed by areduction of 52% at the end of this session. Insummer, dehydration lead to a decrease in the level ofNa+ by 212%. The increase of Na+ level on thebeginning of de;h,~~E~~i,RIl ' -i~~~:I:"ingwinter could beinterpreted as a result of the reduction in the urinevolume (Ghobrial,.)",~70b!(,al'\d ;'i. 1976).The reduction of Na+ concentration during winter<strong>and</strong> summer could be due to the reduction in the level'::;- ·C o ,..' ' " ;.~ 'c' ,"\_ ~ ·'.", ,·,;,;,~,,:;'~?N"''::~~> ·: ;";."'''.~N&::;f'~~~)~1.f~~~i%~~!ri10'.~ '· :!1!5i.( ,ri !iAi· :.'· '' ' ~ ~' ", '. ' :" }L': ,. 'of food intake that ' extremely decreased withcontinuation of dehydration (figs. 42 <strong>and</strong> 43)(Macfarlane et a1., 1961 <strong>and</strong> Ghobrial, 1970b). Also,

., '. ."'.~ . ' " .... '. ".- ....it may be a function of aldosterone as it stimulatesthe distal convoluted tubules of the kidneys <strong>and</strong>increase the rate of reabsorption of Na+ ions (Haggag<strong>and</strong> EI-Husseini, 1974 <strong>and</strong> Sonbol, 1988).Comparisonof the winter results with those of the summer showedan increase in Na+ concentration in all stages of theexperiment.This could be as a result of the increaseof sweating during summer (Taylor, 1972) as some ofNa+ ions excreted with sweating (Ghobria1, 1974).These results are in agreement with those obtained byGhobrial (1974) on Afri gazelle as Na+ level wasdecreased by 43% when it was dehydrated, <strong>and</strong> Jhala atal. (1992)on the black-buck as Na+ concentrationsdecreased by dehydration for about 82%Similarresults were obtained by Choshniak et al. (1984) onthe Bedouin goat.5.4 . 3 Urine potassium (K+):Dehydration during winter lead to an increase inK+ concentration in the urine by 49%, for the first 5days of dehydration. That was followed by a reductionof 13% at the end of this session. In summer, K+concentrations decreased by 16% due to dehydration.The increase of K+ level on the beginning ofdehydration during winter could be interpreted as a. ~

105 during winter <strong>and</strong> summer could be due to the reductionin the level of food which was extremely decreasedwith dehydration (Macfarlane et a1., 1961 <strong>and</strong> Ghobrial1970b) .comparison of the winter results with those ofthe summer showed an increase in K+ concentrations inthe hydration <strong>and</strong> rehydration sessions. This could bedue to the increase of the level of sweating duringsummer (Ghobrial 1970b <strong>and</strong> Taylor, 1972) as some of K+may be excreted with sweating (Ghobrial, 1974).These results are in agreement with thoseobtained by Jhala et a1. (1992) on the black-buck, asK+ concentrations decreased by dehydration for about47%, when the animals dehydrated for 3 days. Similarresults were obtained by Macfarlane et a1. (1961) onthe merino sheep.5.4 Urine chloride (Cl-):­Urine Cl- concentrations were not changedsignificantly by dehydration of the Idmi gazellesduring winter <strong>and</strong> summer. Comparison of the winterresults with the summer ones showed an increase in Clconcentrationsby 43% The decrease in summerdehydration session could be attributed to theincrease in the level of Cl- loss, that was increasedby sweating during summer as a result of hightemperature (Ghobrial, 1974). That could also be due

106 to the differencesioniods of winter <strong>and</strong> summer, as the summer dry matteri was reduced by 64% in(F 1). These results are in agreement with theobta by (1974) on the Afrigazelles (26% decrease), <strong>and</strong>results ofet al. (1984) on the bedouin goat, asdecreased 34%.5.4.5. Ur urea:­Dehydration during winter <strong>and</strong> summer led to anthevolume, hence the concentration level rose.couldtotalin I lowered urea 1through the rumen (Jha et ale , 1992) .Comparison of concentration of summer urine ureawith of revealed an by 58%,60% <strong>and</strong> 62% in all ionIdehydration <strong>and</strong> the rehydration,could be attributed to<strong>effect</strong> of heat on the levelion (Taylor, 1972). This sion may leadto a decrease vo summercomparison with winter urineion. The winter urine volume was more than

107 summer by 255% during dehydration <strong>and</strong> 66% onrehydration, whilst the levels were almost similarbefore <strong>water</strong> <strong>deprivation</strong>. These results are inagreement with those obtained by Ghobrial (1974) onAfri gazelle, as the urine urea increased bydehydration for about 70%.similar results wereobtained by Brown <strong>and</strong> Lynch (1972) on sheep.5.4.6. Urine osmolality (UO):­Gazelle's dehydration during winter led to agradual increase in the level of UO by 78% during thefirst 6 days, then UO was decreased with dehydration.The increase in Uo could be interpreted as due to thedecrease in the volume of urine. On continuation ofdehydration, the level of food intake decreased <strong>and</strong>that may be caused a decrease in the levels of many of, :',:"- c";; ": ';" ';. ,,, :,,-,,'the 'l eleetro ;rytCe 's~an~';Eic:lil~'s1fe~q~~a::t~J Cl- ,~/·4.;:K+ 'Yete~" That ", ~ :5· ~ ' ", , ,have led to a deer'ease in the level of UO1970b) .' : ~,~~: \ :.: ." ..-:..... ~.....

108could be due to the difference in the level of foodintake, as it was greater in winter than in summer by179% (Figs. 42 <strong>and</strong> 43). Ghobrial (1970b) found similarresults on Afri gazelle reporting that the urineosmolality in winter was higher than the UOof thesummer by 14%. Similar results were obtained by Brown<strong>and</strong> Lynch (1972) on sheep.

~.: j'... '.: ' . , .. .. ' .... .,'.. ..'." ... '· , ·-: ~u-

110 6.1 Introduction:­studies on the <strong>effect</strong>s of heat <strong>and</strong> dehydration onthe weight, food <strong>and</strong> <strong>water</strong> intake, <strong>and</strong> feaces moistureof desert animals in general <strong>and</strong> gazelles inparticular are meagre. Presently there are no studieson the <strong>effect</strong> of dehydration <strong>and</strong> heat on these, '." .": ," ",~ '>(~'; ' : ;'~;;i-~~"~~~i;..,~'~4§%,!~~'l;£ l~ ;:': 'c..,.,~:b":' ',:,' ".'parameters on Arabian gazelles. However,there are" ' some "studi'es " ·on '!'>th:e~Sudaheqs~~fr1il.1g 'a""ze;rl'es "''' ( Ghob'r "i a f', '"';', iJ~'"1966, 1967 <strong>and</strong> ' · Moh'i;mm'ed "j;;et~(.~1 ':"';"I:f,\ '1988) · <strong>and</strong> some other.: ", ';~ \! ·F~'::'\':'·:~. :~~;~l~~~·.~•.':f.tj ::~~ :: ~~Y , .. ! ·.~··.~..,,;7-' ~..;." .,'", :,.

111activities in the cooler periods of the day in orderto reduce <strong>water</strong> loss through evaporation <strong>and</strong> hencesecuring a higher level of humidity for feeding.Taylor (1972) in his study on Thompson's gazelle<strong>and</strong> Grant gazelle found that the loss of <strong>water</strong> throughevaporation reachs the highest level duringthemaximum air temperature period of the day. He addedthat the rate of the <strong>water</strong> loss wasreduced byshortage of <strong>water</strong>. He also stated that food humiditywas inversely proportional to heat, this situationenabled the gazelles to go without direct intake of<strong>water</strong>, as they ' benefitted :from the high level of, i· " ' ~ ' ~·"·: ' : ' ·- ( - I-:..-:,"l'·v"-,:,·.• :, ;:, ;- ,,,, -: #:,,_~,:. ~;.:~~,.iiif~.J'''.'~*.t:4.~~~~~~~~~%~e~~ ~ ~.\t.~.,>~$,''k;..,::~;;c ··J., ·, ~ ·.i>;· ·' ( · ~· · '; ~,.8::. ·:::-;humidity in food when the temperature was low. Heexplainedthat ' ~~food ~humid±tY~~,counted " ' :' for;l% ' of .animalbody weight, whllst"-oxidafi'on\';of food provide about 2%of body weight, <strong>and</strong> this spared the animals taking; :<strong>water</strong> directly.This was in agreement with Habibi(1992) on Farasan gazelle (G.gazella farasani) whic~conserves <strong>water</strong> by resorting to crepuscular activitypatterns especially in the hot months of the year, <strong>and</strong>also by gaining <strong>water</strong> through consuming hygroscopicplants in times of moderate heat when the plant leavesare humid due to the high humidity in the isl<strong>and</strong>s.Similar observations were mentioned by Louw <strong>and</strong>Seeley (1982) who reported that animals gain <strong>water</strong>through oxidation of food, humidity of food <strong>and</strong>directly taking <strong>water</strong>. Loss of <strong>water</strong> was reported to

112 be through through <strong>and</strong> skin, <strong>and</strong>faeces <strong>and</strong> . They added that themain factors affecting <strong>water</strong> are solarradiat of animal bodysize, skin structure,speed,<strong>and</strong> activitythe animal.wereby(1992) as the desert ungulates depend on the foodmoisture as a source This physiolog1by a behavioralion astend to take food the cooler tomaxDawson et al. (1989)ungulates e.g. the lIes were no of<strong>water</strong> choose right food <strong>and</strong>right time the wasa high relative humidity.Mohammed et (1988) studied the ofonon theSudanese . He mentioned they loose28.8% ofdehydratbut one hour after rehydration they75% of the lost body weight, then 86.5% oflost weight on fol day. food intakethe mot were reduced by the of42% <strong>and</strong> 4 respectively, <strong>and</strong> rega normal levelson rehydration.

~ .~ :; ' .. ,..; ~ : ' . ~'. , . , .. '. 1 ', ' . .t. '::113Jhala et al. (1992) studied the lowest limit of<strong>water</strong> dem<strong>and</strong> in the black-buck in winter, with theresultant findings that it was so much less than thatof summer due to variations in temperature. They alsofound that the faecal <strong>water</strong> ratio was reduced from 57%to 43% by dehydration in summer due to reabsorption of<strong>water</strong> in the posterior part of the digestive tract.Several studies have been done on domesticanimals living in semi-desert habitats, ego Brown <strong>and</strong>Lynch (1972) on sheep. These dehydrated sheep lost aremarkable ratio of <strong>their</strong> weight, which was attributedto low food intake coupled with loss of body <strong>water</strong> dueto dehydration.Gary et aI. (1979) carried out a similarstudy on the horse that gradually lost body weight by10.7% when the animal dehydrated for 3 days during thesummer. They noticed sickness symptoms like thinningof the body, eyeball retraction <strong>and</strong> backboneprojection. On rehydration the horse consumes <strong>water</strong>about 7% of its body weight within one hour.Degen <strong>and</strong> Young (1981) studied the <strong>effect</strong> ofdehydration on some physiological processes of sheep.They found that faecal <strong>water</strong> content dependedprimarily on food intake <strong>and</strong> not the degree oftemperature, <strong>and</strong> ." they : ~ : added :,-;.that the animals lost 5­13% of the total faecal <strong>water</strong> by dehydration.

114 6 • •6.2.1. GazelA Seca Balance ( SECA Germany) with anaccuracy todur the acclimation period <strong>and</strong> the experiments (2). In winter, the anima were weighed onceevery 48 hInthe hydration <strong>and</strong> dehydrationwere weighed after 2h <strong>and</strong> 24h.In summer,were weonce48 hduranima also were we onceevery 24 h in dehydration. In rehydration, they wereweighed 2h <strong>and</strong> 24h after.The method in weighing zel was asllow: The zel 's wereacloth whilewas in the cage to make it quite.animal carr by h<strong>and</strong> , the total weight ofthe<strong>and</strong> the was . This was1 by thec1Caion:Gazelle's Weight (Kg)the gazel - Weightof theholdingholdingc

1156.2.2: Dry Matter Intake (OMI): This was done in two I the first f Id daily of a known amount of food(alfalfa hay) usingBalance accurate to 1 gm.was put container of thezel 24 h remaining food was then··,·····weighedThe was as anamount the food was weighed us a DHAUS dig 1to 0.01 gm), then put in a g(W.C. HeraeusGmbH-HERAEUS-Postfach 1153) oven 105°C tillreached a weight ( ly 7 h) tofood moisture (Mohamed, 1986) .Calculat.'­1. RFM (%) :::: Weight the 1 Wefood x 100. 2. DMI (g/24h) == IWF _ IWF x RFMOMIIWFdry initial weight of food taken by gazelle/24h. RFM of moisture.

116 of <strong>water</strong>24 h was cafor each zelle skipp a known volume of <strong>water</strong>the <strong>water</strong> conta of icremaining <strong>water</strong> is measured a 24 h.Thewasby pouring same volume of <strong>water</strong> that wasthe 1 the container of themetabolic cage (with no animal)sametime the an Is were given 24 h theremawas;".'(ml/24 h)=initial6.2.3. <strong>water</strong> Intake ):­volumevo24 h.(ml/24 h) = initial volume-volume6.2.4. Moisture (FM):­Faecal(FM) was estimated by collectingsome the animal droppings in a securely closed• 2).then to the 1 (SeeIn the lab the specimens were weighed usaOHAUS dried out by oven HEREUS 7h

117 105°C (Mohamed, 1986) till the aconstant weight, this was followed by weighing the dry1Calcuions:­of (%) :::: Weightbefore drying - after drying x 100.

118 6.3: Results6.3.1.of the Idmi les for 8 days,followed by ion revea a s ifin animal weights (P~O.Ol, F=3.l2). Thean Is we were reduced from 18. 65±1. 57 Kg to15. 38±1. 08 (18%) by . On theanimals we rose to 16.68±1.13 Kg (9%) after 2 h,to 17.98±1.4 Kg after 24 h. This1 was lessthan that dehydrat by 4% (Fig.40).Dehydration the for 3 summer days,lowed by ion a icantdif ( 0.001, F=36.24) the 1 weanima weights were from 19.32±1.58 Kg to15. 83±1. 33 Kg (18%) the end of dehydration. On rehydrat the level was 18. 33±1. 79 after 2 h (16%) then 19 .15±1. 59 after 24 h. This 1 lower than that dehydration only 0.17(Fig. 41). ison of winter with ofthe summer revealed no significant ( . 063 , F= 1 . 6 1 )difference the 1 weights.

119 Hydration Dehydration Rehydration2119 17 15 ~.o 48 96 144 192 240 288 290 312 Hours Fig (40) Variation In mean of weight of gazell08 during the experiment In wlntor.22 Hydra!lonDehydrationRehydration20 16 ­o 48 96 144 168 170 192 HoursFig (41) Variation In mean of weight of gazelles during the experiment In summer.

1206.3.2. Dry Matter Intake (DMI):­Dehydration of the Idmi gazelles during winterfollowed by rehydration revealed a highly significantdecrease (PSO.OOl ,F=7.53) in the level of DMI. TheDMI was reduced from 433±64 g/24 h to 131±14 g/24 h(70%) by the end of dehydration. On rehydration, thelevel of DMI was raised to 448±78 g/24 h. Thisincrease is more than the level before dehydration by4% (Fig.42).During summer, dehydration of these animalsfollowed by rehydration revealed a highly significantdecrease (PSO.001, F=15.36) in the level of DMI.Thelevel of OM! was reduced from 466±120 g/24 h to 47±31g/24 h (90%) by the end of dehydration period. Onrehydration the level increased to 446±45g/24 h(800%). This value is still less than the level beforedehydration by 4%(Fig.43).comparison of the winter results with those ofthe summer revealed a highly significant difference(PSO.001, F=14.89) in the level of DM!, as thereduction was slow in winter until it reached itslowest by the end of dehydration (131±14 g/24 h). Thislevel exceeds the lowest in summer (47±31 g /24 h) by179%, though the winter dehydration period was longerthan the summer one.

121 650 .-----------------~------------------------------------------_r------_.Hydration Dahydrallon Rehydrstiol550450250150 -24 48 72 96 120 144 168 192 216 240 264 288 312 Hours (42) Variation In mean of dry matter Intake (DMI) of gazelles during the experiment In winter.700.------------------------,----------------------,---------.Hydration Oehydralion Rehydration500 -400 -300 -200 -100 1-­24 48 72 96 120 144 168 192HoursFig (43) Variation In mean of dry mattar Intake (OMI) of gazelles during the experiment In summer.

122 6.3.3. Water Intake(WI):­Dehydration during winter followed by rehydrationrevealed a highly significant increase (PsO.001,F=9.17) in the volume of WI, as the level increasedfrom 636±167 ml/24 h(at the normal condition) to1299±141 ml/24 h, an increase of 104% during the first2 h of rehydration, then up to 2369±304 ml/24h (273%)after 24 h of rehydration (Fig.44).During summer, the results showed a highlysignificant increase (PsO.001, F=20.25) in the levelof WI as the level increased from 2184±387 ml/24 h to2566±575 ml/24 h (18%) after 2 h of rehydration, thento 4055±287 ml 24 h (86%) after 24 h of rehydration(Fig.45) .comparison of the winter results with those ofthe summer revealed a highly significant difference(PsO.001, F= 47~ i 90) ;" ; ' as >:the " ~"'summer WI level exceededthe winter level.>;iz:1. , .-~l~ ",~~"~

123 3000 r----------------.----------------------------------------~----------__,Hydration Dehydration Rehydration2500~2000~E'-'(I>.x: 1500

124 On rehydration, the FM level to 43.8±3.3%(30%) as in Fig.46).oflowed by rehydration, revealed a highly sifsummerdecrease (P:::;O.OOl, F=32.94) the FM level as thefrom 49±1.7% to 37.5±O.(24%) byend of the dehydrationI<strong>and</strong> on rehydration theFM level rose to 42.8±2.2% (Fig.47).isonthe winter results with those ofsummer revea no f di .146 ,F=2. 15) the of faeces moisture.

12560 .-----------------~------------------------------------------~----~Hydration Dehydration Rehydralion55 -l50CD...~iii] 46In CD U CG If 403530 L-J-__~L____L____~__~____ ~____L___~____L___~____~__~____~~24 48 72 96 120 144 168 192 216 240 264 288 312HoursFig (46) Variation In mean of faeces moisture of gazelles during the experlmenUn winter.55 ,--------------------------------,,---------------------,-----------,Hydrallon Dehydration RehydrallonlQ)...~50iii·0 45 .­EII)Q)uCGIf4035 ~~______~______~____~______~____~______~____~_______L~o 24 48 72 96 120 144 168 192HoursFig (47) Variation In mean of faeces moisture of gazelles during the exprlment In summer.

126 6.4. Discussion:­During dehydration in winter <strong>and</strong> summer, severalchanges occurred in the gazelle's weight,faecesmoisture <strong>and</strong> the food <strong>and</strong> <strong>water</strong> intake.All of theseare discussed along the following path.6.4.1. Gazelle's Weight:­Dehydration of the gazelles in winter <strong>and</strong> insummer caused a reduction in <strong>their</strong> weight by 18% . Onrehydration they regained 9%. , <strong>and</strong> 16% of <strong>their</strong> lostweight. The levels returned to normal after 24 h ofrehydration. This could be due to the loss of bodyfluids, especially the extracelluar fluids, inaddition to reduction of food intake that accompanieddehydration.Comparison of the winter <strong>and</strong> summer resultsrevealed that there was an equal weight loss duringdehydration despite the difference in the <strong>water</strong><strong>deprivation</strong> periods. On rehydration the increase inbody weight was faster in summer, <strong>and</strong> the weight wasnearly the same as before dehydration, <strong>and</strong> there wasonly 1% difference. In winter the loss after 24 hrehydration was 4% of the original weight beforedehydration. Difference in rehydration could be due tothe difference in <strong>water</strong> intake which was more insummer than in winter. The loss of weight by the endof rehydration session in winter could be attributed

127 to the low food intake coupled with the longerduration of dehydration .These results are in agreement with the findingsof Ghobrial (1966) on the Sudanese Afrigazelles, as they lost 30%of the body weight inwinter <strong>and</strong> 24% in summer when they dehydrated for 5<strong>and</strong> 12 days, respectively; Brown <strong>and</strong> Lynch (1972) onsheep as they lost 10% of the body weight ; Gary etale (1979) on horses, as they lost 10.7% bydehydration for 3 days; Umunna et ale (1981) on Yankasheep <strong>and</strong> Ali et ale (1982) on goat, sheep <strong>and</strong> camels.Similar results were obtained by Mohammedet ale(1988) on the Sudanese Afri gazelle as it lost 29% bydehydration for 10 days.6.4.2. Dry Matter Intake (OMI):­Winter <strong>and</strong> summer dehydration of the Idmi­gazelles followed by rehydration led to a decrease inthe OMI by 70%, <strong>and</strong> 90%, respectively. After 24 h.rehydration the level of OMIreturned to normal. Thelow level of OMI could be attributed to the <strong>effect</strong> ofdehydration on the animals appetite which could haveoriginated fromthe interaction of neuron of theventra-medial hypothalamus where food <strong>and</strong> <strong>water</strong> intakeare regulated on afferent information <strong>and</strong> bloodcomposition (Mohamed , 1986). It could also be due tothe acetate content in food (alfalfa hay) that might

128 have affected the animal appetite. It may also be dueto the dry food that led the animal to reduce thelevel of food intake, as dry food irritates <strong>and</strong> heatsthe stomach (Abdelatif <strong>and</strong> Ahmed, 1993) especially insummer when food humidity was lowest.These results agreed with those of Ghobrial <strong>and</strong>Cloudsley-Thompson (1966) <strong>and</strong> Ghobrial (1967) on Afrigazelle as food intake decreased by dehydration untilit stopped when the animal lost 17% of the body weightdue to dehydration. Similar results were obtained byMousa (1978) on goats <strong>and</strong> sheep <strong>and</strong> resemble those ofUmunna et ale (1981) on Yankasa sheep <strong>and</strong> the resultsof Mohamed (1986) on the Sudanese Afri gazelle as thefood intake decreased by 42% when the animaldehydrated.6.4.3. <strong>water</strong> Intake (WI):­Dehydration of the Idmi gazelles in winter <strong>and</strong>summer followed by rehydration, led to an increase inthe level of WI during the first 2 h of rehydration(104%) <strong>and</strong> after 24 h of this period (650%), comparedwith the WI before dehydration.". ..' ~1 :~' ;"': : ~· t~ ..... ,.~..: ••· '"It was noticed-that the .summer WI was higher thanthe winter level in the period before dehydration, 2h after rehydration, <strong>and</strong> after 24 h by 243%, 98% <strong>and</strong>58% respectively. The excess of WI after rehydrationcompared with that before dehydration could be

129 attributed to the animals dem<strong>and</strong> to compensate thelost body <strong>water</strong> during dehydration which was about 14%<strong>and</strong> 17%of the animal's body weight in winter <strong>and</strong>summer, respectively.The excess level of WIin summer compared withwinter WIcould be due to the increased level ofevaporation that increases with the increase intemperature (Taylor ,1972 <strong>and</strong> Jhala et al.,1992) .Theseresults are in agreement with those of Mohamed (1986)on Afri gazelle as the WIincreased by 228% when theanimals re<strong>water</strong>ed for 24 h. Similar results wereobtained by Jhala et al. (1992) on the blackbuck asthe WI increased by 92% when the animal rehydrated.The amount of <strong>water</strong> consumed by the Idmi gazellesduring the experiment is relatively high, especiallyin summer. The animal usually consumes 3%, <strong>and</strong> 11% ofits body weight of <strong>water</strong> in winter <strong>and</strong> summer,respectively. This could be due to temperature factorsespecially in summer. Another factor could be due tothe high crude protein content in the food (alfalfahay) which when digested high nitrogenous wasteproducts are released which need large amounts of<strong>water</strong> to be excreted through urine <strong>and</strong>sweating(Abdelatif <strong>and</strong> Ahemd, 1993).

130 6.4.4. Faeces moisture (FM):­Dehydration of the Idmi gazelles in winter <strong>and</strong>summer led to a decrease in FM by 32% <strong>and</strong> 24%,respectively. On rehydration the FM was increased by30% <strong>and</strong> 14% in winter <strong>and</strong> summer, respectively.The reduction in FM by dehydration could be dueto the increase in the rate of reabsorption of <strong>water</strong>in the intestine which was induced by the general body<strong>water</strong> loss. These results are in good agreement withthe findings of Ghobrial <strong>and</strong> Cloudsley-Thompson (1966)<strong>and</strong> Mohamed(1986) on the Sudanese Afri gazelle, asthe faeces moisture decreased by 50% <strong>and</strong> 41%,respectively. Similar results were obtained by Musa(1978) on sheep <strong>and</strong> goats, Degen <strong>and</strong> Young (1981) onsheep <strong>and</strong> Jhala et a1., (1992) on the black-buck asthe decrease in faeces moisture was 14%,when theanimal dehydrated for 3 days.

CHAprrER SEVEN GENERAL DISCUSSION

132GENERAL DISCUSSIONCl are the major factors influencedesert animals distribution <strong>and</strong> 1 (Louw <strong>and</strong>Seely, 1982, <strong>and</strong> Dixon Jones, 1988) .The <strong>effect</strong> of in larare main problems these animals (Louw,1993 ) lly wh can not avosolar rad ion (Abdelat <strong>and</strong> Ahmed, 1993) .In the some iolog 1are investaiming to know some of thelIe adaptations to the arid environments.It appears that when G.should have free <strong>water</strong> to drink.was given dry foodIt couldabsence dr 8 days in winter <strong>and</strong> 3in summer whenof <strong>water</strong>.Gazelle'sion during winter <strong>and</strong> summerreflected some physio ical as bodyincreased in summer durdehydration by2.1 °C. s of the the rate oftion to minimizeloss. Similar resultswere obtained by Taylor (1970a) on the Afrungulates <strong>and</strong> 1 (1970b) on s gazelle. Ita be an to ze difbetween the air<strong>and</strong> body temperature.

133 The difference in body temperature was accompanied byseveral changes in the blood parameters, urine volume~nd its content, faeces <strong>water</strong> content, <strong>and</strong> foodintake. These changes are aiming to reduce the <strong>water</strong>loss via urination <strong>and</strong> defecation (Louw, 1993).Dehydration lead to a reduction in the level of plasmavolume, extracelluar fluids <strong>and</strong> all body parts(Choshniak et al., 1984, Mohammed et al., 1988 <strong>and</strong>Sneddon et al., 1993).The decrease in plasma volume is the main <strong>effect</strong>ivefactor that determines survival of the animals(Macfarlane et al., 1961 <strong>and</strong> Gauthier-Pilters <strong>and</strong>Oagg, 1981). As the decrease of plasma volume wouldlead to an increase in the level of blood viscosity<strong>and</strong> hence this may affect the heart adversely(Mohamed, 1986). This would explain the adaptation ofthe desert mammals in general, <strong>and</strong> the camel inparticular for maintaining the plasma volume (Wilson,1984) . The level of blood components duringdehydration show that the shortage of <strong>water</strong> had causeda haemoconcentration in addition to a remarkableincrease in the serum osmolality, BUN, totalprotein <strong>and</strong> albumin. This was accompanied by anextreme decrease in the level of food intake. It wasnoticed that there is aproportional relationshipbetween the level of food intake <strong>and</strong> some of the serumcontents such as Na+, K+, CI- in addition to the totalprotein. This relationship could be explained since

134 the food (alfalfa hay) is the main source of theseparameters, <strong>and</strong> hence the increase or decrease of foodintake would affect the level of these items.The decrease in the level of food intake is associatedwith a decrease in the level of total crude protein.This could be an adaptation to reduce the nitrogenouswaste <strong>and</strong> hence urine volume (Mohamed, 1986). Theproportional relationship between the level of foodintake <strong>and</strong> urine volume support that.Due to the decrease in the level of food intake(especially in summer), some of the serum parameterswere decrease, d sueh as Na, + K + ,C 1­ , serum osmolality<strong>and</strong> BUN.This could be explained as the food is themain source of those items. Similar relationship wasnoticed between the level of food intake <strong>and</strong> urineNa+, K+,Cl-<strong>and</strong> urine osmolality. This could be due tothe same reason.The kidney of the desert mammals plays a major role inconserving <strong>water</strong> (Gauthier-pilters <strong>and</strong> Dagg, 1981).The structure <strong>and</strong> function of <strong>their</strong> kidneys haddeveloped to enable them to cope with desertconditions (Ghobrial, 1976, wilson, 1984 <strong>and</strong> Sonbol,1988). Louw <strong>and</strong> Seely (1982) <strong>and</strong> Grenot (1992)reported that the Henle loops are the main part thathelp these animals to resist drought. They play amajor role in reabsorption of <strong>water</strong> <strong>and</strong> Na+. Kidney's

135 function is controlled by two hormones one of them isthe antidiuretic hormone (ADH)which is produced bythe hypothalamus <strong>and</strong> stored in the posterior part ofpituitary gl<strong>and</strong> . When the osmotic pressure increasesdue to shortage of <strong>water</strong>, ADH is released <strong>and</strong>stimulate the distal convoluted tubules <strong>and</strong> collectingtubules to increase the rate of reabsorption of <strong>water</strong>.The other hormone is aldosterone which is secreted bythe cortex of the adrenal gl<strong>and</strong>. It affects the distalconvoluted tubules <strong>and</strong> stimulates them to increasereabsorption of Na+. This is followed by <strong>water</strong>, due tothe change in the osmotic pressure (Haggag <strong>and</strong> EI­Husseini, 1974, Yagil <strong>and</strong> Etzion, 1979, Gau<strong>their</strong>pilters<strong>and</strong> Dagg, 1981 <strong>and</strong> sonbol, 1988).In general, it could be concluded that <strong>water</strong><strong>deprivation</strong> of the mountain gazelle during winter <strong>and</strong>summer produced some reversible physiological <strong>and</strong>biochemical changes. It seems that this species mightwithst<strong>and</strong> dehydration for relatively long periods in<strong>their</strong> natural habitat. This perhaps explains thepresence of Idmi gazelle on the periphery of thedeserts of northern Saudi Arabia in the NCWCD reservesAI-Harrah <strong>and</strong> Al Khunfah, where no trees <strong>and</strong> permanent<strong>water</strong> (Thouless et al., 1991) <strong>and</strong> in Farasan isl<strong>and</strong>swhere no fresh <strong>water</strong> is available (Habibi,1992).Previous findings agree with those of Dunham et al.(1993) who noticed that the Idmi reintroduced in the

136 Ibex reserve (180 km south west of Riyadh) are welladapted to the new habitat <strong>and</strong> have reduced <strong>their</strong>visits to the source of <strong>water</strong> <strong>and</strong> food supplies.Beside the abovementioned physiologicaladaptations that Idmi gazelle has, there are severalbehavioral adaptations that help the animal inresisting thirst. Habibi (1992) reported that Farasangazelle conserves <strong>water</strong> by resorting to crepuscularactivity patterns especially in summer, <strong>and</strong> also bygaining <strong>water</strong> through consuming hygroscopic plants intimes of moderate heat when plant leaves are humid.Similar observations were reported by Ghobrial (1974)on Afri gazelle as it selects the cooler hours of theday <strong>and</strong> retreats to the shade when air temperature iselevated in order to reduce <strong>water</strong> loss. Also, similarobservations were reported by Grenot (1992) <strong>and</strong> Dawsonet al. (984) on desert ungulates.It should be mentioned that the population ofthis species,in addition to the other Arabiangazelles, have declined in recent years (Groves, 1988<strong>and</strong> Habibi, 1989).Thouless et al. (1991) <strong>and</strong> Greth<strong>and</strong> Williamson, (1994) reported that uncontrolledhunting is the main factor that threatened survival ofthese animalsin addition to other factors e.g.Habitat destruction <strong>and</strong> the uncontrolled development.

137 ConclUB1- The shows that the Idmi gazellecan w ion 8 inwinter <strong>and</strong> for 3 days in summer.s wasascerta by the when the animalwas deprived of <strong>water</strong> on dryalfalfa when was under normalweather c2- zelle res thirst by manyphys log 1 adaptations, such as:a) the of therespiratory system <strong>and</strong> skin.b) This was lowed by thetemperature.c) Reduc urine volume <strong>and</strong> concentratd) the volume in the3 Beside the physiologicalgazelle also benef from the ial

138 Recommendations:To improve measures <strong>and</strong>re for Idmi zelle, folare recommended:1) The areas for ofgazelle should a source of <strong>water</strong>a ial trees (such as acacia .) .Sucharegazel r as the <strong>water</strong> would regulate the an l's body<strong>and</strong> <strong>water</strong> ba<strong>and</strong> the trees wouldprovide food <strong>and</strong> shelters.2) Ana ing the f I thenutrvalue in Idmi3) Assessing ityareas.4) Studying food <strong>and</strong> feeding behaviour Idmi, into the other of iour.The above stud the basi re zelawould help inIn this study<strong>and</strong>zelle iswere not measured. A study all bloodincluding these two hormones in Idmi

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