| The semen freezing and artificial insemination (AI) was conducted in Yuxi local canine. The major object of this paper is to improve the quality of canine frozen semen and increase the pregnancy rate of AI. The main contents are as fellows.( 1 ) The methods of semen collection and the evaluation of seminal characteristics in Yuxi local canine144 ejaculates (tried 164 times) were collected by the improved digital manipulation, as well as 15 ejaculates (tried 20 times) were obtained by an artificial vagina, the success rates were 87.8% and 75.0% resp. Then, the parameters of seminal characteristics in Yuxi local canine were firstly evaluated, which include semen valume, spermatozoa progressive motiliry, semen concentration, pH and the percentage of intact acrosome.(2) Influence of extenders and forms of frozen semen on post-thaw progressivemotiliry of canine frozen semenThe second fraction semen from 36 ejaculates of 6 male Yuxi local dogs were frozen in extender I and extender II with 3 forms of package (pellet, 0.5ml straw and ampule) resp, then the post-thaw progressive motility (PTPM) of the frozen semen was evaluated. The study demonstrated that the mean PTPM of 3 packings for extender I (0.35±0.04) was greater than extender II (0.23±0.05;P<0.01) . The mean PTPM of pellets in both extender I and extender II (0.34±0.08) was greater than that of straws (0.26±0.09;P<0.01) and ampules (0.26±0.08; P<0.01) . There was no difference between straws and ampules (P<0.05).(3) Freezing canine pellet semen by the new method of frying in liquid nitrogen Thirty five fractions of semen samples collected from six male dogs were dilutedand equilibrated. Then each was divided into two equal portions and frozen separately using the following two methods. The new frying method in which the semen were dropped in liquid nitrogen directly for 5-8 seconds,then the pellet semen taken out from liquid nitrogen were frozen on 2 cm above the liquid nitrogen surface for 6 minutes and the common method fluro-plastic plate over liquid nitrogen. The results showed that the new method was better than the common one with the mean post-thaw motilities of semen being 0.385±0.022and 0.331±0.042 (P<0.01), thepercentages of survival sperms 53.57±3.55and 45.75±1.91 (P<0.05) , the percentages of sperms with intact acrosomes 44.60±3.10 and 39.37±5.29 (P< 0.05) respectively.(4) Canine straw semen freezing with programmable freezerThirty -six ejaculates from six male dogs were diluted, quilibrated and packed in 0.5ml straws simultaneously, the only difference being in the programs used for freezing. The straws were frozen with program I and program II in the programmable freezer separately. The mean post thaw progressive motility (PTPM) were 0.47± 0.10 and 0.34±0.05 (P<0.01) resp., and the percentage of sperms with intact acrosome were 34.47±5.20 and 29.77±4.37 (P<0.01) resp. It is concluded that the program I was better than program II for freezing canine straw semen.(5) Artificial insemination of bitch with frozen semenTwo groups of bitch were inseminated with made by ourself inseminating tubes and semen which was frozen by the method of Frying in Liquid Nitrogen. The pregnancy rates of vagina-insemination group and uterine-insemination group was 20% and 57.1% resp. The study demonstrated that the better insemination site was bitch' s uterine lumen; the pellet semen and the one kinds of inseminating tube made by ourself could be used in AI of bitches.
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