Staples C R, Thatcher W W, Clark J H
Dairy Science Department, University of Florida, Gainesville 32611.
J Dairy Sci. 1990 Apr;73(4):938-47. doi: 10.3168/jds.S0022-0302(90)78750-4.
The effect of energy status upon ovarian activity during early lactation was assessed in 54 multiparous Holstein cows. Dry matter intake and milk yield were measured daily from parturition through 9 wk of lactation. Milk composition and body weight were measured weekly during this time. Energy balance corrected for body weight loss was calculated weekly. Blood was collected via tail vein three times weekly and plasma analyzed for progesterone and nonesterified fatty acids. Fifteen cows were anestrus for the 9 wk based on their plasma progesterone (less than 1 ng/ml). These cows were compared with two cycling groups, one group of 25 cows showing corpus luteum activity within 40 d after parturition and a second group of 14 cows showing corpus luteum activity between 40 and 60 d postpartum. Anestrus cows ate less feed, produced less milk, and lost more body weight, resulting in a more negative energy status than cycling cows. Differences in energy balance among cow groups were greatest the first 3 wk postpartum. Anestrus cows and cows showing corpus luteum activity between d 40 and 60 obtained more energy from body reserves for milk production the first 2 wk of lactation, than cows cycling prior to d 40.
在54头经产荷斯坦奶牛中评估了能量状态对泌乳早期卵巢活动的影响。从分娩到泌乳9周期间，每天测量干物质摄入量和产奶量。在此期间每周测量一次牛奶成分和体重。每周计算校正体重减轻后的能量平衡。每周通过尾静脉采集三次血液，分析血浆中的孕酮和非酯化脂肪酸。基于血浆孕酮水平（低于1 ng/ml），15头奶牛在9周内处于乏情期。将这些奶牛与两个发情周期组进行比较，一组25头奶牛在分娩后40天内表现出黄体活动，另一组14头奶牛在产后40至60天之间表现出黄体活动。乏情期奶牛采食的饲料较少，产奶量较低，体重减轻更多，导致其能量状态比发情周期奶牛更负。奶牛组之间的能量平衡差异在产后的前三周最大。与在40天前发情周期的奶牛相比，乏情期奶牛以及在40至～60天表现出黄体活动的奶牛在泌乳的前两周从体储备中获取更多能量用于产奶。 ～这里原文“d 40 and 60”表述似乎有误，推测可能是“40至60天”，按此理解翻译了，你可根据实际情况调整
