D. Badamdorj,1 M. Davaa,2 B. Erdenebaatar,1 B. Dagviikhorol,1 L. Batsuuri,2 J. Gombojaw1 and B. Amarsanaa2
1. Research Institute of Animal Husbandry (RIAH), Zaisan, Ulaanbatar-210153, Mongolia
2. National Yak Research Centre, State University of Agriculture, Zaisan, Ulaanbaatar-210153, Mongolia
Wild yak frozen semen, imported form P.R. China, was used in an experiment on artificial insemination (AI) technique in Mongolian female yak to evaluate the conception rate and obtain 1/2-hybrid progenies. Female yak showing natural (n = 20) and synchronised (n = 20) oestrus were inseminated twice at a 12-hour-intervals. The conception rate of cows calculated on the bases of numbers of calves born was 35.0 and 40.0%, respectively, for the 'natural' and synchronised groups.
Keywords: Artificial insemination, fertility, frozen semen, Mongolian yak, wild yak
Implementations of new breeding techniques have led to an increase in the production and reproductive efficiency in yak husbandry (Wei 1994). Some results have shown that the number of calves born were 92.3% for naturally mated yak cows, while artificial insemination (AI) with wild yak frozen semen has resulted in a figure of 66.1%. Many factors have been shown to influence the conception rate of yak cows on AI (Ben et al. 1994; Pang and Qiao 1994; Zhao and Zhang 1994). This paper reports the results of introducing the wild yak semen to Mongolian domestic yak through the AI approach.
Cows showing natural (n = 20) and synchronised (n = 20) oestrus were inseminated twice at a 12-hour-interval. The frozen semen pellet was thawed at 38°C water for 1 minute. The sperm motility before the insemination was examined, and only semen with motility above 0.4 was used for insemination. At insemination, the thawed semen was deposited in the cervix.
The heat in experimental cows was detected through the use of vasectomiesed males daily and those showing clear signs of heat were inseminated.
A small difference between the two groups in terms of conception rate suggested that both frozen semen and AI techniques work well enough to achieve a reasonable level of conception (Table 1). However, the pregnancy rate in the present study was much lower than that reported by Zhao and Zhang (1994). The difference may be due to the fact that, in the present study, the technical staff involved had much less experience in AI techniques in yak and their ability to detect oestrus was generally poor.
Table 1. Conception rate of cows inseminated with wild yak frozen semen.
Groups |
No. of cows |
Conception rate | |
No. |
% | ||
Animals showing natural oestrus |
20 |
7 |
35.0 |
Animals with synchronised oestrus |
20 |
8 |
40.0 |
Total |
40 |
15 |
37.5 |
The gestation period in the experimental cows was 249 ± 14.5 days and the mean body weight of calves at birth was 14.4 ± 0.81 kg.
The authors are most grateful to the Mountain Livestock Department of RIAH for making available animals and providing additional technical support.
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