Growth, development and hematological parameters of the young stock of yaks

Abstract

There were studied the features of growth and development of the young stock of yaks from birth to 18 months of age as well as their certain hematological parameters. Investigations were carried out in 2012-2014 in the Republic of Tuva. Two groups of the young stock were formed as follows: a control group obtained from second- and third-calved grunting cows with the average indices of live weight, conformation and calf output, and an experimental group consisting of the young stock from grunting cows of the breeding herd with higher characteristics of live weight, conformation and calf output. The animals were kept on pasture all year round from their birth. The maximum rate of growth and development was shown by the experimental young animals. They exceeded the control group’s animals in live weight at birth by 6.2%, at 3 and 6 months of age by 18.4 and 18.0, at 12 and 15 months by 13.2 and 11.3, and at 18 months by 11.7%. For the 18-month raising period, the average daily liveweight gain in the experimental young animals made up 374.8 g per day that was 14.5% more than in the control. Resulting from a study on linear growth, an advantage of the experimental young animals was established as well. Unlike their contemporaries from the control group, they had a deeper, longer and wider body, comparatively short but strong legs, well-expressed conformation and a stronger constitution. Hematological parameters of both groups were within the limits of physiological norm. It was established that blood leukocytes, total protein, calcium and phosphorus contents in the experimental young animals increased, which corresponded to liveweight gain indices.