大约克母猪排卵规律的研究

通过对大约克母猪在发情不同时间分批屠宰测定表明，大约克母猪排卵时间是在发情开始后４８小时左右至７２小时之前这一范围。并采用杜洛克和大约克公猪分别在母猪发情的不同阶段先后配种，从所产仔猪的遗传特征鉴别结果判断，排卵大多集中在发情３６小时后至６０小时左右范围内，与屠宰测定基本一致。据上试验结果，确定掌握适配期为母猪发情开始后３６－４８小时期间第一次配种，间隔１２－２４小时内复配一次。经两年配种实践取得良好效果，情期受胎率分别达到９１．２７％（２０９／２２９）和９３．３６％（２６７／８６）。

A Study on the Ovulation in the Large Yorkshire Sows

By slaughtering sows at different time after the onset of estrus,it was shown that the ovulation began about 40 -72 hours after the beginning of estrus in the large Yorkshire breed. Through mating the sow with hoars from both Durok and large Yorkshire breeds at different time of estrus and identifying the piglets born according to genetic features,it was also found that most ovulation occurred in the period between 36 to 60 hours after the onset of estrus. In view of the above results,the right time for the first mating in the large Yorkshire sows should be in the period of 36-48 hours after the onset of heat and the second mating should occur 12-24 hours after the first. A two-year practice of this mating scheme showed a very good result,and the pregnancy rates reached 91. 27% (209/229) and 93. 36% (267/286).