novel approaches to expression and detection of oestrus in dairy cows

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applicable to every production system such as tie stall cows; detection rate of only 14-20% (Firk et al., 2002), or when cows do not display any activity increase for various reasons; ill health, lameness or when the threshold for increased activity is not reached (Roelofs et al., 2005). 1.5.3.2 Electronic Heat Mount Detectors Electronic heat mount detectors such as HeatWatch are similar to pressure activated heat mount detectors (see Section 1.5.1.5) without the need for visual observation. These radio telemetric devices measure the pressure from standing activity; which is defined as 3 standing events in 4 hours. When activated a radio signal is emitted which is picked up by a receiver/ repeater, relayed to a buffer then ultimately to a computer where the important information for the herdsman is stored. The identity of the cow, time of mount, date and duration are all recorded, and from this timing of heat onset and time for AI can be estimated. Different lists are also generated: oestrus, suspected oestrus, non return (no mounts in 25 days), brief cycle (13 day cycles) and inactive list (At-Taras and Spahr, 2001). Efficiency of detection using electronic heat mount detectors is reported as 86.8%, which was similar to recordings from activity monitors when compared (At-Taras and Spahr, 2001) with a low error rate of 2% (Rorie et al., 2002). However when compared to visual detection electronic heat mount detectors were more efficient, 91% compared to 51%, respectively, due to continuous monitoring and quick identification of cows not showing oestrus. Peralta et al. (2005), however, reported different efficiencies when comparing detection methods under compromised conditions. Visual detection and HeatWatch had similar efficiency; 49.3% and 48% of oestrus periods detected, respectively, with lower efficiency for activity monitors; 37.2%. Moreover, in this study the conception rate for cows detected by HeatWatch was much greater than that of visual detection, 17.3 vs 6.2% respectively. Therefore, electronic heat mount detectors are efficient at detecting oestrus as they monitor continuously. However they only detect standing behaviour and do not take into account secondary signs of oestrus which are important as not all cows stand to be mounted (Dobson et al., 2008). Although their accuracy is compromised by generating a number of false negative diagnoses thought to be caused by uncoordinated mounts not triggering the pressure sensitive device and through several false positives 44
caused by the general environment triggering devices, also incurring error through loss of the transmitter from the tail head (At-Taras and Spahr, 2001), which has been reported by many groups (Firk et al., 2002). 1.5.3.3 Milk Progesterone Biosensors Milk progesterone concentration drops below 3ng/ml of milk at oestrus and can be used as a detection aid for pin pointing the drop in progesterone, allowing oestradiol to increase (Friggens and Chagunda, 2005). Monitoring progesterone concentration is a useful tool for monitoring the reproductive status of the cow throughout the oestrous cycle (discussed in Section 1.5.2.1) and can be automated using an in-line approach monitoring hormone concentration at each milking by biosensors (Delwiche et al., 2001a). The specificity of the sensors can detect subtle changes in concentration and provide details on ovarian function, metabolic status and disease such as mastitis. Numerical data can then be downloaded and compared online and used to determine the health and fertility of cows and most importantly the timing of ovulation (Mottram et al., 2002). These biosensors successfully detected all 19 ovulatory events but the variation in progesterone concentration resulted in a 26% error rate due to variability between cows (Delwiche et al., 2001a). This group made improvements to the sensitivity of the immunoassay and developed usable data available in real-time within 10 minutes of sampling (Delwiche et al., 2001b) yet this method of detection is not fully validated and is not available commercially. HerdNavigator, on the other hand, is a commercial method of online progesterone monitoring which was developed with elements to detect health, fertility and metabolic status (Lovendahl and Friggens, 2008). The model as described by Friggens and Chagunda (2005) has reported 99.2% in the model of confirmed oestrus and 93.7% using ratified oestrus and progesterone curves (Friggens et al., 2008). Monitoring of progesterone concentration does have advantages over other methods of detection because silent ovulations can be detected; 55.2% of first ovulations post partum were silent and detected by milk progesterone concentration but not activity (Ranasinghe et al., 2010). However the accuracy of this technique declines as timing of decrease in progesterone concentration has a weak relationship with timing of ovulation (Lovendahl and Friggens, 2008). 45
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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 and 52: indication for the optimal time to
Page 53 and 54: calving), 3) pre-breeding heat date
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: physical activity and stage of the
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
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5.3 RESULTS Results demonstrate pos
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Figure 5.2 Graph showing mounting b
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Table 5.1 Results from POC 2 showin
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Table 5.3 Efficiency and accuracy o
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oestrus and oestrus it is clear to
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P4 Concentration, ng/ml P4 Concentr
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Page 143 and 144:
Page 145 and 146:
Page 147 and 148:
Activity Activity Activity Activity
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Page 153 and 154:
5.4 DISCUSSION The aim of this work
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averaged 70% which was lower than t
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when the cows lie down, especially
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the level of oestrous activity was
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technology larger herds must be mon
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monitoring could also monitor non-l
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antennae which could affect accurac
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predispose cows to illness e.g. met
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CHAPTER 6 - Overall Discussion & Co
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oestrus, h 2 =0.27 (Lovendahl et al
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The final section of this thesis de
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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
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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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