通过测定生殖道黏液导电性确定小尾寒羊配种时机的观察研究

通过使用羊排卵测定仪准确掌握不同繁殖期小尾寒羊的排卵期,旨在有效提高母羊的受孕率。选择1.5~3.5周岁和4~6周岁小尾寒羊空怀期繁殖母羊各30只,利用羊排卵测定仪测定发情期内母羊生殖道黏液电阻值,研究其变化规律,发现1.5~3.5周岁母羊组发情持续时间较短,电阻值下降和上升均较快;而4~6周岁母羊组发情持续时间较长,电阻值下降较快但其上升曲线较为曲折。比较处于不同阴道黏液电阻值范围的母羊人工授精后的受孕率发现,4~6周岁的羊群组比1.5~3.5周岁的羊群组可受孕范围宽,但1.5~3.5周岁的羊群组在可受孕电阻值范围内受孕率明显高于4~6周岁的羊群组。该研究结果提示,不同年龄小尾寒羊母羊阴道黏液电阻值变化幅度不同,发情周期内电阻值下降到最低点后再上升时期为小尾寒羊的排卵期,适宜配种,该时期为母羊配种受孕率高。

Determination of the Optimum Insemination Time of Small-tailed Han Sheep by Measuring the Conductivity of Genital Tract Mucus

In order to effectively improve the pregnant rate of ewes, this study developed a method to accurately determine the ovulatory time of small-tailed Han sheep in different reproductive periods by using a commercially available sheep ovulation detector. A total of 60 non-pregnant female small-tailed Han sheep 1. 5-3. 5 years of age (n=30) and 4-6 years of age (n=30) were selected, and the ovulation detector were used to determine and characterize the electrical resistance value of genital tract mucus of the ewes during estrous period. The results showed that the ewes 1. 5-3. 5 years of age had shorter duration of estrous period, and the increase and decrease of the electrical resistance value of genital tract mucus had dramatic variations; the ewes 4-6 years of age had longer duration of estrous period, with a rapid reduction and a zigzag ascent of electrical resistance value of genital tract mucus. By comparing the pregnant rate of ewes after artificial insemination with different ranges of electrical resistance value of genital tract mucus, it was found that the ewes 4-6 years of age had wider range of electrical resistance value of genital tract mucus acceptable for successful pregnancy, and in which the ewes 1. 5-3. 5 years of age had higher pregnant rate than that of the ewes 4-6 years of age. In conclusion, the electrical resistance value of genital tract mucus of the ewes with different ages had varied variation amplitude. Furthermore, the ovulation period in an estrous cycle could be determined when the electrical resistance value of genital tract mucus of the ewes drops to the lowest point and then entered a rising period, and insemination during this duration could obtain higher pregnant rate.