novel approaches to expression and detection of oestrus in dairy cows

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1.4 FACTORS AFFECTING OESTROUS EXPRESSION Poor oestrous detection arises due to lack of oestrous expression; decreased duration and intensity and decreased standing behaviour. Factors related to poor expression can be cow related factors; health, nutrition and milk yield, or environmental factors; housing, flooring and stocking density for example. 1.4.1 Environmental Factors 1.4.1.1 Housing Housing design affects oestrous expression. If cows are loose housed in barns then they have the freedom to exhibit oestrous behaviours and the chance of these being observed is improved (Phillips and Schofield, 1990). However, if cows are housed in tie stalls with little cow to cow interaction then they cannot exhibit standing behaviour, so detection is based solely on secondary signs of oestrus, which result in a high incidence of detection error and consequently low conception rates (Ranasinghe et al., 2009). Mounts in cubicle houses have been reported to be less frequent than in open barn housing, 7 mounts per hour compared to 11 mounts per hour respectively. At pasture the number of mounts has been reported to be even lower, 5 mounts per hour (De Silva et al., 1981), possibly due to less frequent contact when in an open space and feeding taking priority (Phillips and Schofield, 1990). 1.4.1.2 Floor Type Floor type has a dramatic effect on oestrous expression. It is documented that cows do not like to be mounted on concrete, particularly when wet, preferring softer surfaces underfoot such as grass, dirt or straw bedding (Britt et al., 1986). When observed on dirt compared to concrete the duration of oestrus was longer, with more total mounts and stands. The duration of oestrus on dirt averaged more than 12 hours for 11 out of 13 cows, whereas only 2 cows displayed on average more than 12 hours on concrete (Britt et al., 1986). The duration of behaviour and number of mounts on rubber covered slats, pasture and straw were all similar, but significantly increased compared to duration and number of mounts on concrete (Boyle et al., 2007). Cows walking on rubber have also been reported to move with a more natural gait, have less bruising of the corium and a lower incidence of lameness. Therefore they are more likely to 22
engage in more natural behaviours including expression of oestrus. However rubber flooring can also be slippery when either wet or worn. If the floor surface is slippery or coarse then mounting behaviour is deterred as cows are hesitant, especially if they have existing foot problems or have previously sustained a fall caused by slippery surfaces (Blowey, 2005). Inclusion of rubber covered slats, with grooves and raised ridges, can improve friction and prevent slipping as well as providing additional cushioning, facilitating increased mounting behaviour (Boyle et al., 2007). Although, Boyle et al., (2007) concluded that flooring surface had little effect on standing oestrus their data suggested that the use of rubber flooring reduced foot injuries, which can also affect oestrus expression (see section 1.4.2.1). 1.4.1.3 Stocking Density Stocking density is the number of cows per unit of space and can affect oestrous behaviour both positively and negatively. Increasing the stocking density can increase the frequency of cows in oestrus meeting and interacting (Orihuela, 2000) as cows in free stall barns display more mounting behaviour than grazing cattle through closeness (De Silva et al., 1981). Conversely, in overcrowded situations cows may not have enough space to display oestrous behaviour and any oestrous expression could be undetected because observation is more difficult with larger numbers of cows in close proximity (Diskin, 2008). If there is insufficient area per cow mounting activity can be indiscriminate, directed towards any cows or nearest herd mates because of the close confinement (Metz and Mekking, 1984). In contrast in spacious areas cows in oestrus can choose who they mount and non-oestrus cows can resist mounting (Diskin, 2008). Close confinement has adverse effects on oestrous detection because animals can be wrongly identified as being in oestrus. Misidentification can occur because of increased number of buttings and aggression which can be mistaken for signs of secondary oestrous behaviour, combined with increased interactions in general (Metz and Mekking, 1984). High stocking densities also can affect expression through related factors; aggression (Metz and Mekking, 1984), overcrowding decreasing the lying time of cattle leading to higher incidence of lameness (Blowey, 2005) and decreases in feed intake because of an increased number of displacements from the feeding area (DeVries et al., 2004). These all have adverse effects on 23
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: There are also changes in normal be
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 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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