novel approaches to expression and detection of oestrus in dairy cows

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monitoring. It is clear from the activity data profiles that all cows reported in oestrus by UWB were confirmed in oestrus by increased activity, with increases in activity from basal levels. The level of maximum activity at oestrus differed per cow ranging from 67-133, but this bears no relationship to duration of oestrus as measured by UWB. This finding relates to the earlier work described in Chapters 2 and 3 because the two measurements of oestrous detection measure different signs of oestrous which could also relate to certain cow factors or SNPs for increased oestrous expression. UWB satisfies the criteria defined by Senger (1994) for the ideal oestrous detection system. Continuous surveillance of the herd is required 24 hours a day to monitor constantly for oestrus, with minimised labour requirements. The real-time onset of oestrus is reported by UWB, and most incidences of oestrus in these trials occurred during unsociable hours when herdsmen would not be present, and cows may not be identified in oestrus. This is in agreement with previous data stating that most oestrous behaviour occurs during 1800 and 0600 hours (Hurnik et al., 1975). The duration of total oestrus in this study averaged 10.7 hours, which is higher than previous reports suggesting the average time of oestrus lasts only 7 hours (Dransfield et al., 1998). However this could be attributed to the number of cows in oestrus at once in this study; oestrous expression is increased when the number of cows in oestrus increases (Hurnik et al., 1975;Van Eerdenburg et al., 2002). Yet this indicates that no matter what time of day oestrus is expressed or how short the duration of oestrus it can still be detected by UWB, despite the range of total oestrus duration between trials varying from 2.0 to 14.0 hours. Furthermore, UWB accurately identified individual cows in oestrus and was able to detect the behavioural events at oestrus that are correlated with ovulation. This work has satisfied the aims of this study as cows approaching oestrus and cows in oestrus can be detected in real-time. This was confirmed both by milk progesterone concentrations to identify stage of the oestrous cycle and by other detection methods; visual observation, CCTV records and activity monitoring. Furthermore the work demonstrated that UWB data could be analysed automatically to detect oestrus, accurately detecting 9 out of 9 cows in oestrus, with the potential to extend to a 100 cow herd. However, one must be careful with the 100% success rate described here as sample size is limited. In order to progress further with this novel 144
technology larger herds must be monitored by UWB to achieve a true detection rate. 5.4.3 Comparison of Methods of Oestrous Detection Oestrous detection in this study was carried out by continuous visual observation and CCTV recording, milk progesterone analysis and activity monitoring, alongside UWB to test proof of concept of a novel technology. Due to the experimental design this study required continuous visual observation 24 hours a day which was necessary to confirm oestrus accurately; all types of primary and secondary oestrous behaviour could be monitored and recorded, which has been reported to achieve 100% accuracy of detection (Van Vliet and Van Eerdenburg, 1996). In a more practical situation, however, visual observation is carried out at set times only twice or three times per day. Time of day, frequency and duration of observations can affect accuracy and efficiency (Roelofs et al., 2010); detection rate at milking decreases by 30-41% (Cavastany et al., 2008) and number of cows detected in standing oestrus increases by 30% when observations increase from 2 x 30 minutes, to 3 x 30 minutes per day (Roelofs et al., 2005). Due to lack of time and/ or willingness, not enough time is dedicated daily to visual observation in a commercial situation and therefore efficiency is poor and detection rate decreases (Lehrer et al., 1992). Efficiency of oestrous detection by visual observation has been reported as 74% when considering all types of oestrous behaviour (Van Vliet and Van Eerdenburg, 1996), but when focussing solely on detection of standing heat during set intervals efficiency is often less than 50% (Roelofs et al., 2006;Van Eerdenburg et al., 2002;Van Vliet and Van Eerdenburg, 1996). Hormone analysis has particular advantages over other methods of oestrous detection because the oestrous cycle is regulated by several key hormones which can all indicate reproductive status of the cow, therefore periodic measurement of a key hormones can be used to predict reproductive status (Delwiche et al., 2001a). Progesterone concentrations decrease to basal over the oestrous period (Friggens and Chagunda, 2005) and allow oestradiol to increase through removal of negative feedback in the absence of progesterone (Reames et al., 2010). However measurement of progesterone concentration is inefficient and time consuming, requiring labour for sample collection, and post processing for analysis of results 145
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NOVEL APPROACHES TO EXPRESSION AND
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TABLE OF CONTENTS TABLE OF CONTENTS
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2.2.3 Statistical Analyses ........
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5.3 RESULTS .......................
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Furthermore, automated software was
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LIST OF FIGURES Figure 1.1 Hormonal
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LIST OF TABLES Table 1.1 Trends in
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LIST OF ABBREVIATIONS ˚ ˚C μM 2D
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CHAPTER 1 - Introduction & Literatu
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the past 50 years and duration of o
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Oestrus growing follicle (Staigmill
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ecomes the main inhibitor of FSH an
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calf at 40-50 days post partum; inv
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al., 2006). However, aged sperm hav
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can occur within 2-3 days, but if t
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educes the incidence of problem cow
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oestradiol, the LH surge and ovulat
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The secondary signs of oestrus can
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There are also changes in normal be
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engage in more natural behaviours i
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1983). Exact explanations and mecha
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2006) and disruption of LH secretio
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1.4.3.2 Milk Yield and Nutrition Di
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influence the ability of the ovary
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cyclicity can be delayed if dietary
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indication for the optimal time to
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calving), 3) pre-breeding heat date
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1.5.2 Physiological Changes Physiol
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1.5.2.3 Body and Milk Temperature T
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physical activity and stage of the
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caused by the general environment t
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may be gained. This is because data
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In summary the objective was to for
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diet, with concentrates at milking.
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oestrus was defined as 3 consecutiv
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The interaction between parity and
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individual oestrus was not signific
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Table 2.4 The effects of the intera
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(361 vs. 578 points, respectively,
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oestrous expression with increasing
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the blood (Sangsritavong et al., 20
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CHAPTER 3 - Single Nucleotide Polym
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population owing to previous select
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Table 3.1 Cont. Follicle Stimulatin
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3.2.4 Sequencing of DNA in the Labo
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was achieved. PCR products were rem
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3.4 DISCUSSION The objectives of th
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fertility and oestrous expression.
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CHAPTER 4 - Development of a Novel
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In summary UWB seems a good option
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Initial tests were carried out to i
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Therefore this demonstrates that X
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which is most important for achievi
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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 147 and 148: Activity Activity Activity Activity
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: the level of oestrous activity was
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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