aistand south~ern afrkca - (PDF, 101 mb) - USAID

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control bmaks down, enormous losses can occur. An extreme example was the breakdown of dipping infrastructure during the war of independence in Zimbabwe, where a compulsory dipping policy had been in force since 1914. Between 1974 and 1979 an estimated one million cattle died, mainly of tick-borne diseases (Lawrence et al, 1980). Research has shown that game animals of varicus species maintain a tick population and tick-borne diseases (Young et al, 1988). Sustainable control methods Stricttickcontrolisdifficulttomaintaininmany countries and more rigorous methods for controlling ticks and tick-borne diseases are being investigated. The broad approach has been to use integrated control measures which include the natural exposure to Anaplasna,Babesia or Cowdria organisms while animals are very young. Other means include immunising older animals with live vaccines; immunisation against ECF by infection and treatment; chemotherapy; and strategic acaricide application to control overwhelming tick infestation or disease challenge. However, the most important element in this control package is the use ofbreeds ofcattle that are genetically resistant to tick infestations, Resistant animals have a tendency towards light tick burdens and require less dipping, making control relatively easy and cheaper. In additior, other biological control methods could be used in support of control methods, e.g. anti-tick grasses (Thompson et al, 1978; Sutherst et al, 1982; Zimmerman et al, 1984) and application of aggregation-attachment pheromone-baited acaricide to single sites on bovine hosts (Rechav et al, 1977; Sonenshine et al, 1979). These approaches require an understanding of the parasites that exist in a particular environment and their epidemiology. It is also necessary to have access to acaricides, vaccines and drugs and to be able to monitor tick infestations and disease outbreaks. Host-resistance to ticks It has long been recognised that some animals, or whole breeds, consistently carry fewer ticks than others kept in the same environment (Roberts, 1968a; Wagland, 1975). Such differences are caused by variation in the apimals' abilities to respond immunologically to tick infestation (Roberts, 1968b). The ability to develop resistance is heritable (Hewetson, 1972; Seifert, 1984) and the actual manifestation is acquired (Rick, 1962; Roberts, 1968a). It is stable over longer periods, although stresses such as lactation or sickness cause a drop in resistance (Wharton et al, 1970; Seifert, 1971; Utech et al, 1978). Different levels of resistance occur in all breeds, but this is manifested more strongly in zebu cattle and their crosses (Riek, 1962; 120 Wilkinson, 1962; Wharton et al, 1969; Seifert, 1971; Hewetson, 1979). The improved tick control following the use of tick-resistant cattle has been demonstrated in various breeds of cattle and crossbreds (Riek, 1962). Kelly (1943) suggested that the tick resistanre, of zehu cattle should be utilised for tick control. Moreover, a cross between zebu and taurine cattle was shown to carry fewer ticks and required less dipping than temperate breeds of cattle on similar pastures (Wharton et al, 1969). The criteria for the assessment and quantification of resistance to ticks in cattle are given in many reviews (Willadsen, 1980; Tatchell, 1986; Latif and Pegram, 1992). Resistant animals consistently carry fewer ticks than susceptible animals. Female ticks completing engorgement are fewer and smaller on resistant animals than on susceptible animals. Tick-resistant cattle in Africa The earlier observations on cattle mortality due to heartwater and its relation to the number of ticks on animals of different breeds made by Bonsma in 1940s (Bonsma, 1981) in South Africa formed the basis of the studies on host-resistance to tick infestationr. The study showed that Africander cattle carried far fewer ticks than British beef cattle and had a far lower mortality rate than the British cattle (6% vs 60%). This pioneer work by Bonsma was resurrected by researchers in Africa 40 years later.Assessment and quantification of host-resistance were carried out on several African indigenous breeds of cattle (Table 1). The majority of these breeds are tick-resistant and of high productivity (Trail and Gregory, 1982; Saeed et al, 1987). The work shown in Table 1 comprises short-term studies (up to two years) carried out to assess the levels of host-resistance in different breeds of cattle. There has been only one long-term programme aimed at raising herd resistance by selection, breeding or gene alteration (de Castro, 1991); this was based at the International Centre of Insect Physiology and 7cology, Kenya. Although the progress and results obtained were meaningful and in the right direction, the programme was terminated after three years due to lack of funding and expertise. Over 100 hulls and 450 heifers at the Boran National Stud were assessed for tick resistance by repeated monthly exposure to ticks. The proportion of bulls ranked in different classes for total tick counts (Table 2) showed that the majority (55%) of these animals had a high level of resistance (rank 1) while a smaller proportion (6%) were ranked as of low resistance (rank 3). The repeatability of the observations suggests a high degree of heritability of resistance.
Table 1. Trkk-resistantzebu cattle in Africa. Breed Country Reference Afrikander South Africa Bonsma (1940) in Bonsma (1981) Brahman South Africa Rechav (1987), Rechav et a (19S0) Bonsmara South Africa Scholtz et at (1991) Ngunis-Nkoni (Sanga) South Africa Scholtz et at (199 1) Boran Kenya East African Zebu Kenya Kenana Sudan Butane Sudan Boran Ethiopia Horro Ethiopia Nkoni (Sanga) Zimbabwe Conclusions Current control of ticks and tick-borne diseases in Africa is unsatisfactory, costly and requires excessive effort. Therefore a package for intograted control of ticks and tick-borne diseases is presented. The features of the strategy are: maintenance of enzootic stability to tick-borne diseases, adoption of resistant breeds of cattle; and reduction of chemical treatments to low levels. Similar methods of integrated control have also been suggested by Young et al (1988). The future of breeding programmes for tick resistance is two steps ahead of breeding for trypanotolerance because, firstly, vaccination against tick-borne diseases is possible and, secondly, resistant breeds of different types are present in most regions ofAfrica. References Bonema J C. 1981. Breeding tick-repellent cattle. In: Whitehead G B and Gibson J D (eds), ick biology andcontrol.Tick Research Unit, Rhodes University, Grahamstown, South Africa. pp. 67-77. de Castro J J. 1991. Resistance to ixodid ticks in cattle with an assessment of its role in tick control in Africa. In: Axford R F E and Owen J B (ods), Breeding for disease resistance in farm animals, CABI, Wallingford, UK. Hewetson R W. 1972. The inheritance of resistance by cattle to cattletick. Australian Veterinary Journal 48:299-303. Hewetson R W. 1979. Results of selection for cattle tick resistance in cattle. Proceedingsof the 56th Annual ConferenceofAustralianVeterinaryAssociation.pp. 91-93. Kelley R B. 1943. Zebu cross cattle in Northern Australia. An ecological experiment. CSIR AustraliaBulletin. LatifAA. 1984. Resistance to natural tick infestations in different breeds of cattle in the Sudan. Insect Science Application 5:95-97. LatifAA and Pegram R G.1992. Naturally acquired host resistance in tick control in Africa. Insect Science Application 13: in press. LatifAA, Punyua D K, Nokoe S and Capstick P B. 1991. Tick infestations on zebu cattle in Western Kenya: Individual host variation. Journalof Medical Entomology 28:114-121. Lawrence J A. 1991. Retrospective observations on the geographical relationship between Rhipicephalus 121 de Castro (1991) Latif et al (199 1) Latif (1984) Latif (1984) All (1989) in : de Castro (1991) All (1989) in: de Castro (1991) Norval et a] (1988) Table 2. Frequency of bulls (100) ranked by total tick counts for six months, Boran National Stud, Kenya. Rank % Resistance 1 55 High 2 39 Middle 3 6 Low Source: Adapted from do Castro (1991). Research into trypanotolerant cattle has received long-term support from donor agencies and research institutes. The use of cattle resistant to tick infestations (zebus and their crosses) and its effective role in tick and disease control needs support and priority in research. appendiculatusand East Coast fever in Southern Africa. VeterinaryRecord 128:180-183. Lawrence J A, Foggin C M and Norval R A I. 1980. The effects of war on the control of diseases of livestock in Rhodesia (Zimbabwe). Veterinary Record 107:82-85. Mukhebi A W, Perry B D and Kruska R. 1992. Estimated economics of theileriosis control in Africa. Preventive Veterinary Medicine 12:73-85. Norval R Al, Sutherst R W, Kurki J,Gibson J Dand Kerr J D. 1988. The effect of the brown ear-tick Rhipicephalus appendiculatus on the growth of Sanga and European breed cattle. Veterinary Parasitology30:149-164. Rechav Y. 1987. Resistance of Brahman and Hereford cattle to African ticks with reference to serum gammaglobulin levels and blood composition. ExperimentalApplied Acarology 3:219- 232. Rechav Y, Dauth J and Els D A. 1990. Resistance of Brahman and Simmentaler cattle to Southern African ticks. OnderstepoortJournalof Veterinary Research57:7-12. Rechav Y, Parolis H, Whitehead G B and Knight H M. 1977. Evidence for an assembly pheromone(s) produced by males of the bont tick Amblyomma hebraeum (Acarina: Ixodidae). Journalof Medical Entomology 14:395-400. Rick R F. 1962. Studies on the reactions of animals to infestation with ticks. VI Resistance of cattle to infestatioi with the tick Boophilus microplus.
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FPTREOF LIVESTOCK INIWSTRIES ', AIS
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ISBN 92-9053-,271--a Correct citati
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Disease control approaches Economic
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Preface John Walsh Director General
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and communal farmers develop the in
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The impact of the introduction of e
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Table 3. Productivity ol Tswanacros
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contribute much more than exotic ca
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Intensive animal feeding practices
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Table 1. Annual dry-mattur producti
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Table 3. Nutritional composition an
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Table 6. Nutritional composition an
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Table 10. Dry matter Intake and por
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Lilongwe, Malawi, 5-9 December 1988
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Figure 2. The analyical framework.
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Figure 3. Group composition and lin
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Dairy/beef production systems resea
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Table 2. Constraints to beef/dalry
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Table 5. The performance of Holstei
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Research on smallholder dairy produ
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are a small number of productive an
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establishing a time frame sufficien
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secondary data analyses. In each ar
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facilitate greater orientation to f
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References Goldson J. 1973. The eff
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Sumnary Smallholder dairy on-farm r
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country relies on the development o
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To estimate the productivity of int
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S n x Ethiopia's population, is est
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Results temperate climate of sub-Sa
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igurel. #O-mcaf 9RHVM pedm im eat B
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References Beyene Kebede. 1987. The
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* train a number of Kenyans for hig
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Figure 1. Comparative milk off-take
Page 69 and 70: Table 2. On-farnn flock composiion
Page 71 and 72: Market demand for DPGs and DPG prod
Page 73 and 74: Contribution of cros;sbred goats to
Page 75 and 76: The project staff are closely invol
Page 77 and 78: Dairy goat research and extension a
Page 79 and 80: Table 2. Main objectives of fte res
Page 81 and 82: Table 3. Daitygoat management at SU
Page 83 and 84: Table 6. Performanceof does atSUA f
Page 85 and 86: Summary Dtal-purpose cattle in cent
Page 87 and 88: the establishment of good managemen
Page 89 and 90: Technologies introduced in the farm
Page 91 and 92: circumvent this problem the "Open N
Page 93 and 94: Pert-urban small-scale dairy resear
Page 95 and 96: Research methodology Project implem
Page 97 and 98: government centre between 1935 and
Page 99 and 100: emphasis to improvements in the mil
Page 101 and 102: Table 1. Agro-ecological zones of Z
Page 103 and 104: Table 2. Productivity of indigenous
Page 105 and 106: government institutions as research
Page 107 and 108: Disease control approaches
Page 109 and 110: ditions occur mostly in calves and
Page 111 and 112: ments to maintain dipping infrastru
Page 113 and 114: Lawrence J A and McCo(kcr P J. 1981
Page 115 and 116: experiences so far gained and futur
Page 117 and 118: acceptance s very high and the work
Page 119: Sustainable control methods for tic
Page 123 and 124: Summary New vaccine strategies agai
Page 125 and 126: Uilenberg G, Zivkovic D, Dwinger R
Page 127 and 128: Table 1. Tsetse infested area in co
Page 129 and 130: Objectives ofte research programme
Page 131 and 132: aspect. needs urgent attention. Val
Page 133 and 134: ingoats. Tropical Animal HeathandPr
Page 135 and 136: Summary Smallholder dairy productio
Page 137 and 138: Factors affecting the development a
Page 139 and 140: Most roads in the rural areas where
Page 141 and 142: well-focused dairy development prog
Page 143 and 144: Secure better bargaining position w
Page 145 and 146: purchase fuel and lubricants in the
Page 147 and 148: part of the country. The cattle pop
Page 149 and 150: " to increase farm-family income of
Page 151 and 152: Recent developments in the dairy in
Page 153 and 154: Dairy development programme in Tang
Page 155 and 156: Table 3. Popu/aon andpro&ctke kicak
Page 157 and 158: Table 5. Napier production on-farm
Page 159 and 160: facilities, unreliable trnsport, la
Page 161 and 162: Smallholder dairy development progr
Page 163 and 164: various types of cattle under rural
Page 165 and 166: 38,657 (US$ 7957) have been achieve
Page 167 and 168: labour to meet the requirements of
Page 169 and 170: Development of smallholder dairying
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Table 3. Revenue and expenditure fr
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Marketing options for livestock pro
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argaed that the only way to improve
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Debrah and Axrteneh (1991) found ma
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Mbogoh S G and Tilahun N. 1992. Dai
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Group ranch concept and practice ir
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the land, reducing the capacity of
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Furthermore, Goldschmidt (1981) sta
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upgraded with Sahiwal breed (Kajiad
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the project in 1982. Infrastructura
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If all the ranches were subdivided
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This can be achieved through an ext
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Introduction of dairy cattle produc
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" a permanent water source should b
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Development of feeding strategies a
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Supplementation improved milk yield
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Sweet potato vines, pigeon pea leav
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Summary Wool and mohair production
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contributed to low fecundity was th
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established with the following obje
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qualified staff at LIC& haa been a
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Synthesis of constraints to livesto
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i'nd appropriateness of the technol
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" Realising the magnitude of the pr
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DrL. Reynolds International Livesto
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