Badinga L, Collier R J, Thatcher W W, Wilcox C J
J Dairy Sci. 1985 Jan;68(1):78-85. doi: 10.3168/jds.S0022-0302(85)80800-6.
Breeding records, representing 12,038 inseminations at Bassett's Dairy Farm (Monticello, FL), were analyzed to document effects of environmental and management factors on fertility of dairy cattle from January 1, 1975 to December 31, 1977. Conception rates of lactating cows decreased sharply when maximum air temperature on day after insemination exceeded 30 degrees C. In contrast, conception rates for heifers did not decline until 35 degrees C. Virgin heifers had higher conception rates for all services (50%) than lactating cows (34%) and suffered only slight depression of fertility during summer months. Heifers required 1.5 services per conception compared with 2.3 for lactating cows. Relationship between conception rate and rainfall on day after insemination was negative and curvilinear. Jerseys had higher conception rates (45%) than Holstein (39%) and Brown Swiss (41%). Services per conception were 1.7, 2.0, and 1.9. Substantial decreases of fertility were associated with advancing service number. Estrous status (standing; positive heat detection patch; mounting activity), inseminator, and year of service were related to variation of conception rate. Seasonal effects on fertility of lactating cows were marked. Thus, environmental management of the postpartum cow during hot summer months is warranted to maximize fertility.
对巴塞特奶牛场（佛罗里达州蒙蒂塞洛）1975年1月1日至1977年12月31日期间代表12,038次授精的繁殖记录进行了分析，以记录环境和管理因素对奶牛繁殖力的影响。授精后次日最高气温超过30摄氏度时，泌乳奶牛的受孕率急剧下降。相比之下，小母牛的受孕率直到35摄氏度时才下降。未产小母牛所有配种的受孕率（50%）高于泌乳奶牛（34%），且在夏季受孕率仅略有下降。小母牛每次受孕需要1.5次配种，而泌乳奶牛则需要2.3次。授精后次日的受孕率与降雨量之间呈负相关且为曲线关系。泽西牛的受孕率（45%）高于荷斯坦牛（39%）和瑞士褐牛（41%）。每次受孕的配种次数分别为1.7次、2.0次和1.9次。繁殖力的大幅下降与配种次数增加有关。发情状态（站立；发情检测贴片呈阳性；爬跨行为）、输精员和配种年份与受孕率的变化有关。泌乳奶牛的繁殖力存在明显的季节性影响。因此，在炎热的夏季对产后奶牛进行环境管理，以最大化繁殖力是有必要的。
