Garmo R T, Martin A D, Thuen E, Havrevoll Ø, Steinshamn H, Prestløkken E, Randby A, Eknaes M, Waldmann A, Reksen O
Department of Production Animal Clinical Sciences, Norwegian School of Veterinary Science, NO-0033 Oslo, Norway.
J Dairy Sci. 2009 Oct;92(10):4919-28. doi: 10.3168/jds.2009-2104.
Progesterone profiles in Norwegian Red cows were categorized, and associations between the occurrence of irregularities in the profiles and the commencement of luteal activity were investigated. The cows were managed in 3 feeding trials from 1994 to 2001 and from 2005 to 2008 at the Norwegian University of Life Sciences. The cows were followed from calving, and the milk samples collected represented 502 lactations from 302 cows. Milk samples for progesterone analysis were taken 3 times weekly from 1994 throughout 1998 and from 2005 to 2008 and 2 times weekly from 1999 to 2001. Commencement of luteal activity was defined as the first day of 2 consecutive measurements of progesterone concentration >or=3 ng/mL not earlier than 10 d after calving. Delayed ovulation type I was defined as consistently low progesterone concentration, <3 ng/mL for >or=50 d postpartum. Delayed ovulation type II was defined as prolonged interluteal interval with milk progesterone measurements <3 ng/mL for >or=12 d between 2 luteal phases. Persistent corpus luteum (PCL) type I was defined as delayed luteolysis with milk progesterone >or=3 ng/mL for >or=19 d during the first estrous cycle postpartum. Persistent corpus luteum type II was defined as delayed luteolysis with milk progesterone >or=3 ng/mL for >or=19 d during subsequent estrous cycles before first artificial insemination. Delayed ovulation type I was present in 14.7%, delayed ovulation type II in 2.8%, PCL type I in 6.7%, and PCL type II in 3.3% of the profiles. Commencement of luteal activity was related to milk yield, parity, PCL type I, and the summated occurrence of PCL type I and II. The least squares means for the interval to commencement of luteal activity were 24.2 d when PCL type I and II were present and 29.5 d when PCL type I and II were absent. The likelihood of pregnancy to first service was not affected in cows with a history of PCL when artificial insemination was carried out at progesterone concentrations <3 ng/mL (i.e., during estrus); however, cows that had experienced PCL were more likely to be inseminated during a luteal phase. The occurrence of delayed ovulation and PCL in Norwegian Red cows was less than that reported in most other dairy populations.
对挪威红牛的孕酮水平进行了分类，并研究了孕酮水平异常与黄体活动开始之间的关联。这些奶牛在1994年至2001年以及2005年至2008年期间于挪威生命科学大学进行了3次饲养试验。从产犊开始跟踪这些奶牛，所采集的牛奶样本代表了302头奶牛的502次泌乳。1994年至1998年以及2005年至2008年期间，每周采集3次用于孕酮分析的牛奶样本；1999年至2001年期间，每周采集2次。黄体活动开始被定义为产后不早于10天连续两次孕酮浓度测量≥3 ng/mL的第一天。I型排卵延迟被定义为产后≥50天孕酮浓度持续较低，<3 ng/mL。II型排卵延迟被定义为两个黄体期之间的黄体间隔延长，牛奶孕酮测量值<3 ng/mL持续≥12天。I型持久黄体（PCL）被定义为产后第一个发情周期中黄体溶解延迟，牛奶孕酮≥3 ng/mL持续≥19天。II型持久黄体被定义为在首次人工授精前的后续发情周期中黄体溶解延迟，牛奶孕酮≥3 ng/mL持续≥19天。在所有记录中，I型排卵延迟占14.7%，II型排卵延迟占2.8%，I型PCL占6.7%，II型PCL占3.3%。黄体活动开始与产奶量、胎次、I型PCL以及I型和II型PCL的总发生率有关。当存在I型和II型PCL时，黄体活动开始的间隔的最小二乘均值为24.2天；当不存在I型和II型PCL时，为29.5天。当在孕酮浓度<3 ng/mL（即发情期）进行人工授精时，有PCL病史的奶牛首次输精的受胎率不受影响；然而，经历过PCL的奶牛在黄体期更有可能进行输精。挪威红牛中排卵延迟和PCL的发生率低于大多数其他奶牛群体的报道。
