Gwazdauskas F C, Wilcox C J, Thatcher W W
J Dairy Sci. 1975 Jan;58(1):88-92. doi: 10.3168/jds.S0022-0302(75)84523-1.
Data representing 5,062 services during 1960 to 1971 in the Florida Agricultural Experiment Station dairy herd were analyzed by least squares to delineate factors affecting conception rates. Overall conception rate was 37.9%. From a set of 21 climatological measurements, the five selected as most important ranked (1) maximum temperature day after insemination, (2) rainfall day of insemination, (3) minimum temperature day of insemination, (4) solar radiation day of insemination, and (5) minimum temperature day after insemination. Warm months were more closely associated with lower conception rates than were cool months (33.7 compared to 40.1%); month effects appeared to be accounted for by the climatological measurements. Conception rates declined with age: heifers, 47.6%; young cows, 42.7%; older cows, 31.9%. No decline with advancing service number (1 to 5) occurred. Service sire and inseminator effects were detected as expected. Although breeds differed (Aryshires, 33.8; Brown Swiss, 34.6; and Guernseys, 37.0; Holsteins, 35.5; and Jerseys, 48.4%), there was no evidence of breed (Jerseys and Holsteins) by month or breed by season interactions nor was it possible to detect age by season interactions.
对佛罗里达农业试验站奶牛群1960年至1971年期间的5062次配种服务数据进行了最小二乘法分析，以确定影响受孕率的因素。总体受孕率为37.9%。从21项气候测量数据中，选出最重要的五项，排名依次为：（1）输精后次日最高温度；（2）输精日降雨量；（3）输精日最低温度；（4）输精日太阳辐射量；（5）输精后次日最低温度。温暖月份的受孕率低于凉爽月份（分别为33.7%和40.1%）；月份效应似乎可以由气候测量数据来解释。受孕率随年龄增长而下降：小母牛为47.6%；青年母牛为42.7%；成年母牛为31.9%。受孕率并未随输精次数的增加（1至5次）而下降。正如预期的那样，检测到了配种公牛和输精员的影响。虽然不同品种的受孕率存在差异（艾尔夏牛为33.8%；瑞士褐牛为34.6%；根西牛为37.0%；荷斯坦牛为35.5%；泽西牛为48.4%），但没有证据表明品种（泽西牛和荷斯坦牛）与月份或品种与季节之间存在交互作用，也无法检测到年龄与季节之间的交互作用。
