B. Amarsanaa,1 B. Erdenebaatar,2 V. Dagviikhorol3 and D. Badamdoji2
1. State University of Agriculture, Zaisan, Ulaanbaatar-210153, Mongolia
2. Research Institute of Animal Husbandry, Zaisan, Ulaanbaatar-210153, Mongolia
3. High Mountain Department, Research Institute of Animal Husbandry, Zaisan, Ikhtamir sum, Arkhangai Province, Mongolia
This study was undertaken in 1999 to investigate the growth pattern in young crossbred calves produced by inseminating Mongolia domestic yak cows with frozen semen of wild yak imported from China. The measurements taken were body weight and linear body measurements at birth, at 7 days and at 14 days of age. Thirteen crossbred semi-wild yak calves were compared against 13 domestic yak calves and 13 Khainag calves (crosses of cattle bulls mated with female yak). The later two groups were taken as controls. These studies were undertaken in Ikhtamir sum, Arkhangai Province.
The F1 (wild × domestic) yak calves were brown in colour, with dark brown and black stripes over the top line of the body, and whitish spots around the orbits. Ears were shorter by 1.8–2.3 cm than those of domestic yak calves. The body wool covers were also shorter by 0.8–1.2 cm, with top ends rolled up. The animals were sensitive to the presence of humans and dogs and tended to quickly get away. Natural instincts in newborns, such as sucking and ability to recognise their mothers, were highly developed compared to that in domestic and Khainag calves. They quickly stood up, say, between 15–18 minutes after birth.
The average body weight of F1 calves was 13.4 kg at birth, while that of the domestic yak and Khainag calves was 12.1 and 15.1 kg, respectively. After two weeks the F1 calves added 2.9 kg (21.6%), which was 2.6–3.5 times higher than that the net weight gain of the two control groups over the same period. Daily body weight gain for the first two weeks of neonatal life in the F1 calves was 0.207 g, while corresponding values for the domestic and Khainag calves were 0.107 and 0.071 g (Figure 1).
Figure 1. Growth rate of F1 domestic and Khainag yak calves (kg).
To provide specific details on conformation differences, if any, between the F1 calves and the controls, basic linear body measurements were obtained for building a conformation profile. The body measurements of domestic yak calves at birth were used as reference (i.e. 100% in Figure 2) and those of the other two groups were calculated in relation to these. In terms of the basic linear body measurements, F1 calves took an intermediate position between the domestic yak calves and khainag calves. The F1 calves had higher withers height, had short and narrow heads. The chest was deeper and wider than domestic yak calves.
Figure 2. Comparative body conformation profile.
Purebreeding has been the dominant practice in yak production in Mongolia. Due to rapid decline in heterosis from cattle-yak hybrids when mated with one of the other parental species, the share of khainag yak in the total yak population has been very limited (Zagdsuren 1994). No remarkable improvement in the productivity of yak is also achieved because of infertility of male khainag yak. This is a major constraint to this kind of crossbreeding in the yak. Thus, crossing of yak with the genus Bos is not always recommended as a means to increase productivity. To explore opportunities of using wild yak populations to increase growth, a series of studies have been conducted in China (Yang et al. 1997) which showed increases in both growth and milk yield. Specifically, Yang et al. (1997) reported that F1 calves were heavier at birth and had higher body measurements (body height, heart girth and cannon girth). The findings of the present study are generally in agreement with these previous results.
Rongzhen Y., Xiaolin L., Quan L., Jingtao X., Kexuan W. and Yaping W.. 1997. Report on growth and development of domestic yak progenies rejuvenated by wild yak. In: Rongchang Zh., Jianlin H. and Jianping W. (eds), Proceedings of the 1st international congress on yak held in Lanzhou, P.R. China, 4–9 September 1994. Supplement of Journal of Gansu Agricultural University, Lanzhou, P.R. China. pp. 21–25.
Zagdsuren Y. 1994. Some possibilities to increase meat and milk production of yak husbandry. In: Rongchang Zh., Jianlin H. and Jianping W. (eds), Proceedings of the 1st international congress on yak held in Lanzhou, P.R. China, 4–9 September 1994. Supplement of Journal of Gansu Agricultural University, Lanzhou, P.R. China. pp. 113–118.
