Santolaria Pilar, López-Gatius Fernando, Sánchez-Nadal José Antonio, Yániz Jesús
Instituto de Investigación de Ciencias Ambientales de Aragón (IUCA), Escuela Politécnica Superior, Universidad de Zaragoza, 22071 Huesca, Spain.
J Reprod Dev. 2012;58(3):366-70. doi: 10.1262/jrd.2011-035. Epub 2012 Mar 28.
The aim of this study was to evaluate the effect of body weight (BW) change during the early postpartum period and BW on day 50 post partum on the subsequent expression of estrus and fertility at first insemination before day 90 post partum. The data were derived from 1036 postpartum cows reaching 90 days in milk. The following data were recorded for each animal: lactation number, daily milk production at day 50 post partum, calving date, days in milk at estrus and at AI, insemination date, insemination number, inseminating bull, AI technician and body weight at calving, at day 50 post partum and at AI. Of the 1036 cows registered, 817 (78.9%) showed first estrus before day 90 post partum and were inseminated. Using logistic regression procedures and based on the odds ratio a one unit (kg) increase in the daily milk production at day 50 post partum and a one unit (kg) decrease in the BW between calving and day 50 post partum were related to a 1.03-fold increase and a 0.97-fold decrease in the estrus expression rate before day 90 post partum, respectively. Of the 817 cows inseminated before day 90 post partum, 437 became pregnant (53.5%). A one unit increase in the BW at day 50 post partum produced a 1.003-fold increase in the early fertility rate. Pregnancy rate before day 90 was also influenced by the season at calving, bull providing semen and technician. In conclusion, the register of BW during the postpartum period may be a useful tool for evaluating the nutritional status and its relationship with the subsequent reproductive efficiency in dairy cows.
本研究的目的是评估产后早期体重（BW）变化以及产后第50天的体重对产后90天内首次输精时发情和受孕的后续表现的影响。数据来源于1036头产奶90天的产后奶牛。记录了每头动物的以下数据：泌乳次数、产后第50天的日产奶量、产犊日期、发情和输精时的泌乳天数、输精日期、输精次数、输精公牛、输精技术员以及产犊时、产后第50天和输精时的体重。在登记的1036头奶牛中，817头（78.9%）在产后90天内首次发情并接受了输精。使用逻辑回归程序，基于优势比，产后第50天日产奶量每增加1个单位（千克）以及产犊至产后第50天体重每减少1个单位（千克），分别与产后90天内发情表达率增加1.03倍和降低0.97倍相关。在产后90天内接受输精的817头奶牛中，437头怀孕（53.5%）。产后第50天体重每增加1个单位，早期受孕率增加1.003倍。产后90天前的受孕率还受产犊季节、提供精液的公牛和技术员的影响。总之，产后期间体重记录可能是评估奶牛营养状况及其与后续繁殖效率关系的有用工具。
