Department of Livestock and Pasture Science, University of Fort Hare, P. Bag X1314, Alice 5700, South Africa.
Anim Reprod Sci. 2010 Apr;118(2-4):140-7. doi: 10.1016/j.anireprosci.2009.07.006. Epub 2009 Jul 26.
A study was conducted to determine the seasonal trends in ovarian activity, conception and pregnancy status of cows on communal rangelands in the Eastern Cape Province of South Africa. Ovarian activity and pregnancy status of 200 cows were determined through trans-rectal palpation in June, and October 2007 and January 2008. Month of conception was obtained by subtracting the estimated age of the foetus from the month when pregnancy diagnosis was performed. Body weights and body condition scores (BCS) were collected every month between March 2007 and January 2008. Although cows in the perennial grasslands had higher (P<0.05) body weights and BCS than those in the annual grasslands, they had a significant weight and condition loss between March and October. More than 90% of the cows in the annual grasslands were cycling in January (P<0.05). Over 60% of the cows in the perennial grasslands conceived between December and March compared to 46% in the annual grasslands. About 40% of the cows were pregnant in June in the annual and perennial grasslands. There were more cycling and pregnant cows with a BSC of 3 in the perennial grasslands in June and October compared to annual grasslands (P<0.05). Odds ratio estimates of cows exhibiting ovarian activity and pregnancy in the communal areas were highest for BCS. It was concluded that most cows conceived and exhibited ovarian activity between November and March, especially in the perennial grasslands. Future research should focus on supplementary feeding using locally available feed resources to improve cow reproductive performance in the dry months, particularly in the annual grasslands.
本研究旨在确定南非东开普省公有牧场奶牛的卵巢活动、受孕和妊娠状况的季节性趋势。2007 年 6 月、10 月和 2008 年 1 月，通过直肠触诊对 200 头奶牛的卵巢活动和妊娠状况进行了检测。受孕月份通过从妊娠诊断月份中减去胎儿的估计月龄来确定。体重和体况评分（BCS）于 2007 年 3 月至 2008 年 1 月之间每月采集。尽管多年生草地的奶牛体重和 BCS 高于一年生草地（P<0.05），但它们在 3 月至 10 月之间体重和体况明显下降。超过 90%的一年生草地奶牛在 1 月（P<0.05）处于发情周期。与一年生草地相比，多年生草地的奶牛有超过 60%的奶牛在 12 月至 3 月之间受孕，而一年生草地为 46%。在一年生和多年生草地中，约有 40%的奶牛在 6 月怀孕。与一年生草地相比，在 6 月和 10 月，多年生草地中 BCS 为 3 的发情和妊娠奶牛数量更多（P<0.05）。在公有地区，BCS 越高，奶牛表现出卵巢活动和妊娠的几率比估计越高。结论是，大多数奶牛在 11 月至 3 月之间受孕并表现出卵巢活动，尤其是在多年生草地。未来的研究应集中在使用当地可用的饲料资源进行补充喂养，以提高奶牛在旱季的繁殖性能，特别是在一年生草地。
