Petersson K-J, Gustafsson H, Strandberg E, Berglund B
Department of Animal Breeding and Genetics, Swedish University of Agricultural Sciences, Centre for Reproductive Biology in Uppsala, PO Box 7023, SE-750 07 Uppsala, Sweden.
J Dairy Sci. 2006 Jul;89(7):2529-38. doi: 10.3168/jds.S0022-0302(06)72328-1.
The incidence of normal and atypical progesterone profiles in Swedish dairy cows was studied. Data were collected from an experimental herd over 15 yr, and included 1,049 postpartum periods from 183 Swedish Holstein and 326 Swedish Red and White dairy cows. Milk progesterone samples were taken twice weekly until initiation of cyclical ovarian activity and less frequently thereafter. Progesterone profiles were 1) normal profile: first rise in milk progesterone above the threshold value before d 56 postpartum, followed by regular cyclical ovarian activity (70.4%); 2) delayed onset of cyclical ovarian activity: low milk progesterone the first 56 d postpartum (15.6%); 3) cessation of cyclical ovarian activity: ovarian activity resumed within 56 d postpartum, but ceased for a period of 14 d or more (6.6%); and 4) prolonged luteal phase: ovarian activity resumed within 56 d postpartum, but milk progesterone remained elevated in the nonpregnant cow for a period of 20 d or more (7.3%). Swedish Holsteins had 1.5 times higher risk of atypical profile than Swedish Red and Whites. Risk of atypical profiles was 0.5 and 0.7 times lower for older cows compared with first-parity cows; 2.3 times higher for cows in tie-stalls compared with those in loose housing; 2.6 times higher for cows calving during winter compared with summer; 0.5 times lower for cows in earlier (1994-1999) calving-year groups compared with the most recent (2000-2002); 2.5 times higher for cows with planned extended calving interval compared with conventional calving interval; and 2.2 times higher for an atypical profile in previous lactation compared with a normal profile. Cows with atypical profiles had a 15-d increase in interval from calving to first artificial insemination and an 18-d increase in interval from calving to conception. Progesterone samples taken within the first 60 d postpartum were used to calculate the percentage of samples above the threshold value of luteal activity. This measure had a significantly different mean in profiles and can be used to separate delayed onset of cyclical ovarian activity profiles and prolonged luteal phase profiles from normal. Thereby, it may be a more effective tool than measurements based only on the onset of ovarian cyclical activity in genetic evaluation of early postpartum fertility in dairy cows.
对瑞典奶牛正常和非典型孕酮水平情况的发生率进行了研究。数据收集自一个试验牛群，时间跨度超过15年，涵盖了183头瑞典荷斯坦奶牛和326头瑞典红白花奶牛的1049个产后阶段。每周采集两次牛奶孕酮样本，直至出现周期性卵巢活动开始，之后采集频率降低。孕酮水平情况分为：1）正常情况：产后56天前牛奶孕酮首次升至阈值以上，随后出现规律的周期性卵巢活动（70.4%）；2）周期性卵巢活动开始延迟：产后前56天牛奶孕酮水平较低（15.6%）；3）周期性卵巢活动停止：产后56天内卵巢活动恢复，但停止14天或更长时间（6.6%）；4）黄体期延长：产后56天内卵巢活动恢复，但未怀孕奶牛的牛奶孕酮在20天或更长时间内保持升高（7.3%）。瑞典荷斯坦奶牛出现非典型情况的风险比瑞典红白花奶牛高1.5倍。与头胎奶牛相比，年龄较大的奶牛出现非典型情况的风险低0.5倍和0.7倍；与散栏饲养的奶牛相比，拴系牛舍饲养的奶牛出现非典型情况的风险高2.3倍；与夏季产犊的奶牛相比，冬季产犊的奶牛出现非典型情况的风险高2.6倍；与最近（2000 - 2002年）产犊年份组的奶牛相比，较早（1994 - 1999年）产犊年份组的奶牛出现非典型情况的风险低0.5倍；与常规产犊间隔的奶牛相比，计划延长产犊间隔的奶牛出现非典型情况的风险高2.5倍；与正常情况相比，前一胎出现非典型情况的奶牛再次出现非典型情况的风险高2.2倍。出现非典型情况的奶牛从产犊到首次人工授精的间隔增加15天，从产犊到受孕的间隔增加18天。产后前60天内采集的孕酮样本用于计算高于黄体活动阈值的样本百分比。该指标在不同情况中的均值有显著差异，可用于将周期性卵巢活动开始延迟和黄体期延长的情况与正常情况区分开来。因此，在奶牛产后早期繁殖力的遗传评估中，它可能是比仅基于卵巢周期性活动开始情况的测量更有效的工具。
