Denis-Robichaud Jose, LeBlanc Stephen J, Jones-Bitton Andria, Silper Bruna F, Aoki Cerri Ronaldo L
Department of Population Medicine, University of Guelph, Guelph, ON, Canada.
Applied Animal Biology, Faculty of Land and Food Systems, University of British Columbia, Vancouver, BC, Canada.
Front Vet Sci. 2018 Aug 31;5:210. doi: 10.3389/fvets.2018.00210. eCollection 2018.
The ability of automated activity monitoring (AAM) systems to detect estrus is influenced by multiple variables. The luteal phase (LP) preceding estrus has been shown to be important for hormones release, and behavior during estrus in ruminants, but its impact on activity as measured by AAM systems has not been studied. The objective of this study was to investigate the impact of the length of the preceding LP on the intensity and duration of estrus as measured by AAM, and on the expression of estrogen receptor alpha (ERα) in the endometrium. A total of 60 cows between 46 and 53 days in milk were assigned to either a normal or a short length LP. Length of the LP was insured by the use of hormonal synchronization programs. Cows in both treatments were matched on parity, milk production, body condition score (BCS), and lameness score (assessed at enrolment). Expression of ERα receptors in the endometrium were evaluated by nuclear staining by immunohistochemistry of biopsies. Estrus was defined as the day on which the AAM system detected estrus. Cows that were not synchronized by the protocol or that were not detected in estrus by the AAM systems were excluded, which left 21 and 11 cows for analyses in the normal and short length LP, respectively. Peak activity index of estrus, duration of estrus, and expression of ERα were outcomes for multivariable linear regression models. Cows with short length LP tended to have lower peak activity at estrus, but there was no significant effect of treatment when BCS was accounted for. Cows with BCS ≤ 2.5 had less intense and shorter estrus than cows with BCS ≥ 2.75. There was no association between the length of the LP and the expression of ERα in the endometrium.
自动活动监测（AAM）系统检测发情期的能力受多种变量影响。发情期之前的黄体期（LP）已被证明对反刍动物发情期的激素释放和行为很重要，但尚未研究其对AAM系统测量的活动的影响。本研究的目的是调查前一个LP的长度对AAM测量的发情期强度和持续时间以及子宫内膜中雌激素受体α（ERα）表达的影响。总共60头产奶46至53天的奶牛被分配到正常长度或短长度的LP组。通过使用激素同步程序确保LP的长度。两种处理的奶牛在胎次、产奶量、体况评分（BCS）和跛行评分（入组时评估）方面进行匹配。通过活检免疫组织化学的核染色评估子宫内膜中ERα受体的表达。发情期定义为AAM系统检测到发情的那天。未通过该方案同步或未被AAM系统检测到发情的奶牛被排除，分别留下21头和11头奶牛用于正常长度和短长度LP组的分析。发情期的峰值活动指数、发情期持续时间和ERα的表达是多变量线性回归模型的结果。LP短的奶牛在发情期的峰值活动往往较低，但在考虑BCS时，处理没有显著影响。BCS≤2.5的奶牛发情期强度较低且持续时间较短，而BCS≥2.75的奶牛则相反。LP的长度与子宫内膜中ERα的表达之间没有关联。
