novel approaches to expression and detection of oestrus in dairy cows

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5.5 CONCLUSION These trials have provided evidence and proof of concept that UWB can be used for the purpose of oestrous detection. The software and communications have been developed to detect oestrus in order to identify cows entering into oestrus; mounting and those in standing oestrus; standing to be mounted. This information is reported in real-time, and therefore gives provides a measure for predicting time of ovulation. Furthermore all cows identified in oestrus by UWB were confirmed in oestrus by other physiological and physical measurements. These findings are of importance to the dairy industry, where other methods of oestrous detection lack adequate efficiency and accuracy; hence UWB can fill this niche. Through continuous, automated monitoring UWB is efficient, and yet accurate at detecting the definitive sign of oestrus relating to ovulation which enhances the accuracy. The current weaknesses of UWB were identified, although these were mainly due to the prototype stage of development. With appropriate development by decreasing the size of units, increasing battery power and improving script analysis to eliminate error, UWB has the potential to revolutionise oestrous detection through novel positioning technology. Furthermore a future refined product could incorporate a sensor system to integrate UWB positioning and activity monitoring, with algorithms to analyse both data sets simultaneously to strengthen oestrous detection. The current research has provided an insight into the potential of UWB and identified areas for further investigation. Future work would be to monitor oestrous detection in larger herd sizes and investigate several herds in order to conclude whether UWB could significantly improve oestrous detection rates in more commercial scenarios. By predicting the onset of standing to be mounted in real-time and thus providing an optimal timing for insemination, further work should investigate how UWB can improve submission rates and thus conception rates. 152
CHAPTER 6 – Overall Discussion & Conclusions 6.1 OVERALL DISCUSSION Declining fertility in dairy cows has become an international problem strongly associated with genetic selection for high milk yield with little selection for other traits (Royal et al., 2000a;Butler, 2003;Pryce et al., 2004). A major part of the decline in fertility can be attributed to poor detection of oestrus (Van Eerdenburg et al., 2002). It is crucially important for cows to express oestrus and for oestrus to be detected in order for AI to occur at an appropriate time relative to ovulation (Evans and Walsh, 2011). Therefore detection of oestrus is a key determinant of profitability in dairy herds (Pecsok et al., 1994). Poor detection of oestrus can be attributed to the decline in oestrous expression. The number of cows standing to be mounted has declined from 80 to 50% (Dobson et al., 2008) and oestrus is less intense and of shorter duration, averaging only 7 hours in Holsteins (Dransfield et al., 1998). The decline in oestrous detection has been associated with larger herd sizes with the average herd size in the UK increasing from 75 cows in 1996 to 123 cows by 2011 (DairyCo, 2012c). This does vary worldwide with some herds in China and America having 15000 cows. Less labour per cow and a general lack of time dedicated to oestrous expression may also contribute to poor oestrous detection rates. Currently the national average for oestrous detection rate is only 50% where there is potential to be much higher and achieve a realistic target of over 70% (DairyCo, 2009). Traditionally oestrous detection was performed by visual observation and although this method is accurate at detecting oestrus events which occur during observation periods (Van Vliet and Van Eerdenburg, 1996), due to time constraints and impracticality it is largely inefficient (Lehrer et al., 1992). Continuous visual observation of synchronised cows (Chapter 5) detected all cows in oestrus, but continuous observation is not a viable method for commercial use. Many oestrous detection aids are available, with different detection efficiencies and accuracies (Roelofs et al., 2010). Automated methods of detection are becoming increasingly popular, but there is still scope for improvement of detection rates. Activity increases at oestrus (Farris, 1954;Kiddy, 1977) and activity monitoring is a convenient way of detecting oestrus. Detection rates for activity monitoring are often 80 to 90% (Firk et al., 2002), some even 153
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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
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that UWB is matching the ‘truth
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mounting cow. For example height ch
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Backpack 1 st put on in AI stalls E
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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
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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: predispose cows to illness e.g. met
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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