Caton J S, Jesse G W, Day B N, Ellersieck M R
J Anim Sci. 1986 May;62(5):1210-4. doi: 10.2527/jas1986.6251210x.
One-hundred crossbred gilts were used in an experiment that was designed to examine the effects of duration of boar exposure on the proportion of gilts reaching first estrus. Two replicates (summer and fall) of 50 gilts each were randomly assigned, within litter, to one of the following treatments: 1) 30 min of daily boar exposure, 2) 15 min of daily boar exposure, 3) 5 min of daily boar exposure, 4) continuous fence-line boar exposure, plus walked to a neutral pen and exposed to a different boar for 10 to 15 min daily, or 5) continuous fence-line boar exposure. Boar exposure lasted for 30 d. The percentage of gilts exhibiting first estrus by 210 d of age ranged from a high of 65.0 for treatment 4 to a low of 10.0 for treatment 5. Treatments 1, 3 and 4 were greater than treatment 5 (P less than .05), but not different from treatment 2. There were no differences in average age at first estrus. Treatment means for days to puberty after boar exposure were not different (P greater than .05). However, a significant treatment X season interaction occurred. This interaction appears to suggest seasonal trends. These results indicate that treatments 1 and 4 (30 min daily and continuous fence-line boar exposure plus 10 to 15 min, respectively) were the most effective methods tested for the induction of first estrus.
100头杂交后备母猪用于一项实验，该实验旨在研究公猪接触时长对后备母猪达到初情期比例的影响。将两个重复组（夏季和秋季）各50头后备母猪在同窝内随机分配到以下处理之一：1）每天接触公猪30分钟；2）每天接触公猪15分钟；3）每天接触公猪5分钟；4）持续在围栏边接触公猪，另外每天赶到一个中性栏舍并接触一头不同的公猪10至15分钟；或5）持续在围栏边接触公猪。公猪接触持续30天。到210日龄时出现初情期的后备母猪百分比，从处理4的65.0%的高位到处理5的10.0%的低位不等。处理1、3和4高于处理5（P小于0.05），但与处理2无差异。初情期的平均年龄无差异。公猪接触后达到初情期的天数的处理均值无差异（P大于0.05）。然而，出现了显著的处理×季节交互作用。这种交互作用似乎表明存在季节性趋势。这些结果表明，处理1和4（分别为每天30分钟和持续在围栏边接触公猪加10至15分钟）是所测试的诱导初情期最有效的方法。
