novel approaches to expression and detection of oestrus in dairy cows

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1.5.1.1 Behavioural Scoring Van Eerdenburg et al., (1996) developed a scoring system to aid visual detection (Table 1.2). Standing to be mounted was included as the top score that a cow was in oestrus but behavioural scoring also takes into account secondary signs of oestrus (see Section 1.3). Using primary and secondary signs of oestrus allowed all aspects of oestrus to be monitored and the associated scores accumulated a total for oestrous behaviour (Van Vliet and Van Eerdenburg, 1996). When a score of over 100 points was achieved within a 24 hour period the cow was deemed in oestrus. Using this scale and 12 observations for 30 minutes per day in a 6 week study a detection rate of 100% was achieved for all normally cycling cows (Van Eerdenburg et al., 1996). However 12 observations per day is impractical and time consuming. Therefore a more practical method of 3 observations for 30 minutes per day and a threshold of 50 points was developed which achieved 74% detection rate (Van Eerdenburg et al., 1996). Behavioural scoring is a reliable method of visual observation because it includes all behaviour that is associated with oestrus. Yet this method does not give an indication of the onset of oestrus and therefore does not relate to the optimal time for AI. Table 1.2 Table of behavioural scores relating to particular oestrous behaviours. When a total of 100 points is reached within a 24 hour period the cow is judged to be in oestrus (Van Eerdenburg et al., 1996) Oestrus Symptoms Scoring Scale Other Symptoms Mucus vaginal discharge 3 Cajoling 3 Restlessness 5 Sniffing/licking of the ano-genital region 10 Chin resting/ rubbing 15 Mounting Symptoms Mounted by other cow but resisting mount 10 Mounting (or attempting to mount) other cows 35 Mounting head of other cows 45 Standing heat 100 1.5.1.2 Fertility Records Recording all heats is essential for good breeding management and in cases of infertility is the first thing to refer to. Animals must be clearly identifiable by ear tag, freeze mark or other method which should be detectable from a distance when observing. Breeding records should include: 1) animal I.D., 2) calving date (plus information relevant to 36
calving), 3) pre-breeding heat dates, 4) service dates, sire and inseminator, 5) date of pregnancy and 6) expected calving date and any previous problems such as post partum diseases (Diskin and Sreenan, 2000). Records allow improved efficiency allowing farmers to work out the cycles of particular cows calculating approximate dates of oestrus and identifying any cows that have not shown oestrus for further attention, although do not directly aid identification of cows in oestrus. 1.5.1.3 Synchronization To aid oestrous detection and improve submission rates synchronisation protocols (discussed in Section 1.2.2.3) can be used to synchronise the oestrous cycle. Synchronisation allows for a predetermined time period in which cows should display oestrus which aids detection as the herdsmen knows when and which cows to observe (Diskin and Sreenan, 2000). Furthermore some protocols involved fixed timed AI which removes the need for detection of oestrus altogether (Thatcher et al., 1989). Detection is also enhanced by synchronising the oestrous cycles of a group of animals; therefore the intensity of oestrus is increased making detection easier (Hurnik et al., 1975). 1.5.1.4 Teaser Animals A bull among the herd can aid visual detection by detecting subtle signs of oestrus that humans cannot, identifying cows in oestrus. Bulls are often more accurate at detecting oestrus than humans. Vasectomised bulls known as teasers are a useful aid to detecting oestrus as they still allow for controlled breeding (Holmann et al., 1987) and have been reported to marginally improve submission rates, 69% vs 61%, on 5 herds (Gordon, 2006). Androgenised (treated with testosterone or oestradiol) cows or steers, or cows with follicular cysts (with elevated oestradiol production) have increased expression of oestrus (Van Eerdenburg et al., 2002) and can act in the same way as a teaser bull to encourage displays of oestrus and identify cows in oestrus. However use of bulls can incur problems as bulls may develop a preference for certain cows mounting these more frequently and ignoring others. This can complicate detection. Preference may also be given to the SAG ignoring any cows in oestrus outside of this group (Foote, 1975). The presence of a bull can also upset the herd dynamics and decrease female-female mounting. This can make detection of cows in oestrus more difficult as responsibility for oestrous detection is 37
Page 1 and 2: NOVEL APPROACHES TO EXPRESSION AND
Page 3 and 4: TABLE OF CONTENTS TABLE OF CONTENTS
Page 5 and 6: 2.2.3 Statistical Analyses ........
Page 7 and 8: 5.3 RESULTS .......................
Page 9 and 10: Furthermore, automated software was
Page 11 and 12: LIST OF FIGURES Figure 1.1 Hormonal
Page 13 and 14: LIST OF TABLES Table 1.1 Trends in
Page 15 and 16: LIST OF ABBREVIATIONS ˚ ˚C μM 2D
Page 17 and 18: CHAPTER 1 - Introduction & Literatu
Page 19 and 20: the past 50 years and duration of o
Page 21 and 22: Oestrus growing follicle (Staigmill
Page 23 and 24: ecomes the main inhibitor of FSH an
Page 25 and 26: calf at 40-50 days post partum; inv
Page 27 and 28: al., 2006). However, aged sperm hav
Page 29 and 30: can occur within 2-3 days, but if t
Page 31 and 32: educes the incidence of problem cow
Page 33 and 34: oestradiol, the LH surge and ovulat
Page 35 and 36: The secondary signs of oestrus can
Page 37 and 38: There are also changes in normal be
Page 39 and 40: engage in more natural behaviours i
Page 41 and 42: 1983). Exact explanations and mecha
Page 43 and 44: 2006) and disruption of LH secretio
Page 45 and 46: 1.4.3.2 Milk Yield and Nutrition Di
Page 47 and 48: influence the ability of the ovary
Page 49 and 50: cyclicity can be delayed if dietary
Page 51: indication for the optimal time to
Page 55 and 56: 1.5.2 Physiological Changes Physiol
Page 57 and 58: 1.5.2.3 Body and Milk Temperature T
Page 59 and 60: physical activity and stage of the
Page 61 and 62: caused by the general environment t
Page 63 and 64: may be gained. This is because data
Page 65 and 66: In summary the objective was to for
Page 67 and 68: diet, with concentrates at milking.
Page 69 and 70: oestrus was defined as 3 consecutiv
Page 71 and 72: The interaction between parity and
Page 73 and 74: individual oestrus was not signific
Page 75 and 76: Table 2.4 The effects of the intera
Page 77 and 78: (361 vs. 578 points, respectively,
Page 79 and 80: oestrous expression with increasing
Page 81 and 82: the blood (Sangsritavong et al., 20
Page 83 and 84: CHAPTER 3 - Single Nucleotide Polym
Page 85 and 86: population owing to previous select
Page 87 and 88: Table 3.1 Cont. Follicle Stimulatin
Page 89 and 90: 3.2.4 Sequencing of DNA in the Labo
Page 91 and 92: was achieved. PCR products were rem
Page 93 and 94: 3.4 DISCUSSION The objectives of th
Page 95 and 96: fertility and oestrous expression.
Page 97 and 98: CHAPTER 4 - Development of a Novel
Page 99 and 100: In summary UWB seems a good option
Page 101 and 102: Initial tests were carried out to i
Page 103 and 104:
Therefore this demonstrates that X
Page 105 and 106:
which is most important for achievi
Page 107 and 108:
Figure 4.9 Horizontal - Vertical Di
Page 109 and 110:
that UWB is matching the ‘truth
Page 111 and 112:
mounting cow. For example height ch
Page 113 and 114:
Backpack 1 st put on in AI stalls E
Page 115 and 116:
Cows’ behaviour was assessed at 5
Page 117 and 118:
or that the cows were in an area of
Page 119 and 120:
plane, but mostly in achieving high
Page 121 and 122:
Develop techniques for analysis of
Page 123 and 124:
in elastic silicone moulded over a
Page 125 and 126:
and time of mount, duration of moun
Page 127 and 128:
observed matched with increases in
Page 129 and 130:
5.3 RESULTS Results demonstrate pos
Page 131 and 132:
Figure 5.2 Graph showing mounting b
Page 133 and 134:
Table 5.1 Results from POC 2 showin
Page 135 and 136:
Table 5.3 Efficiency and accuracy o
Page 137 and 138:
oestrus and oestrus it is clear to
Page 139 and 140:
P4 Concentration, ng/ml P4 Concentr
Page 141 and 142:
Page 143 and 144:
Page 145 and 146:
Page 147 and 148:
Activity Activity Activity Activity
Page 149 and 150:
Page 151 and 152:
Page 153 and 154:
5.4 DISCUSSION The aim of this work
Page 155 and 156:
averaged 70% which was lower than t
Page 157 and 158:
when the cows lie down, especially
Page 159 and 160:
the level of oestrous activity was
Page 161 and 162:
technology larger herds must be mon
Page 163 and 164:
monitoring could also monitor non-l
Page 165 and 166:
antennae which could affect accurac
Page 167 and 168:
predispose cows to illness e.g. met
Page 169 and 170:
CHAPTER 6 - Overall Discussion & Co
Page 171 and 172:
oestrus, h 2 =0.27 (Lovendahl et al
Page 173 and 174:
The final section of this thesis de
Page 175 and 176:
ate. By using UWB in a commercial s
Page 177 and 178:
provides an insight the potential o
Page 179 and 180:
BLOWEY, R. (2005) Factors associate
Page 181 and 182:
ovine gonadotrophin releasing hormo
Page 183 and 184:
GINTHER, O. J., KOT, K., KULICK, L.
Page 185 and 186:
associated with embryonic survival
Page 187 and 188:
ody condition at parturition on end
Page 189 and 190:
Signs in a 24-h Tie-Stalled Dairy H
Page 191 and 192:
SHERMAN, E. L., NKRUMAH, J. D., MUR
Page 193 and 194:
Influence of negative energy balanc
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