Semen Cryopreservation And Artificial Insemination In Tibetan Mastiff

Semen was collected from the Tibetan Mastiff and semen cryopreservation and artificial insemination technologies were investigated to to improve the quality of canine frozen sperm and increase the pregnancy rate of AI. propagate in the current research..(1)The methods of sperm collection were developed and semen evaluation was conducted. 94 ejaculates (tried 98 times) were collected by the improved digital manipulation, as well as 3 ejaculates (tried 23 times) were obtained by an artificial vagina, the success rates were 95.9% and 13.0%, respectively. The semen characteristics in Tibetan Mastiff were firstly evaluated, which include sperm valume(2.0±0.10～2.9±0.16ml), spermatozoa progressive motility(0.88±0.01～0.95±0.004); sperm concentration(2.2±0.06～2.8±0.06×10~8/ml), pH(6.4±0.08～6.6±0.06), the percentage of intact acrosome(4.8±0.06～7.4±0.18%) and the variation of GOT(236±3.0～422±5.2IU/ml).(2)The extenders on sperm freezing were screened and semen were diluted and evaluated. The mixed sperm from six dogs was frozen in extenderⅠand extenderⅡwith different pH and different time of equilibrium, then the post-thaw progressive motility (PTPM) of the frozen semen was evaluated. The study demonstrated that the mean PTPM in extenderⅠwas better than extenderⅡ, and the mean PTPM (0.41±0.052) in pH6.5 in extenderⅠwas better than in pH5.5 and pH7.5 (P＜0.05), but there were no difference among pH6.0, pH 6.5 and pH 7.0(P＞0.05), and as the equilibrium time was 20min, the mean PTPM (0.42±0.015)in extenderⅠwas better than other's time (P＜0.05).(3)Method of semen cryopreservation was developed in Tibetan Mastiff. The mixed sperm from six dogs was frozen in extenderⅠof pH6.5 with 3 forms of package (pellet, 0.5ml straw and ampule), then the post-thaw progressive motility (PTPM) of the frozen semen was evaluated. The study demonstrated that the mean PTPM of pellets(0.424±0.015) was better than ampules(0.374±0.032, P＜0.05) and straws(0.38±0.029, P＜0.05), and there was no diference between straws and ampules (p＞0.05).(4)The method of artificial insemination in Tibetan Mastiff was investigated. Two groups of bitches were inseminated with inseminating tubes and sperm frozen by the method of pellets. The pregnancy rates of vagina-insemination group and uterine-insemination group was 40% and 80%. The study demonstrated that the suitable insemination site was bitch's uterine lumen,and the pellet sperm and the kind of inseminating tube made by ourself could be used in AI of Tibetan Mastiff.