Impact of Feeding and Management on the Reproduction,Growth and Development of Ganan Yak and Crossbred Progeny

To analyze the impact of feeding and management of yak bulls and cows on reproduction performance,growth and development of Gannan yak cows and their crossbred progenies,Datong yak bulls or their frozen semen were used to mate or A.I with 203 Gannan yak cows.Nutrition supplement were strengthened for all tested bulls,cows and crossbred progenies by supplementary feeding,extending grazing period or early weaning.Oestrus rate,conception rate and calf live rate of natural-mated yak cow were raised for 9.19%、11.03%、14.10%,abortion rate and calf death rate were decreased for 3.3% and 3.87%,respectively.Meanwhile,oestrus rate,conception rate and calf live rate of A.I.yak cow were raised for 6.74%,5.48% and 10.52%,abortion rate and calf death rate were decreased for 4.07% and 4.62%,respectively.After feeding and management were improved,birth weight of bull and cow calf were increased for 19.80% and 14.22%,i.e.2.93 kg and 2.07 kg and body weight of male and female calf at 6 month age were increase for 17.45% and 16.88%,i.e 12.82 kg and 12.23 kg.It implied that no matter artificial insemination or natural mating,Tatong yak bulls could improve growth and development of Gannan yak and it is efficient way to improve the reproduction performance of Ganna yak cow and growth of crossbred progenies by strengthen feeding and management of bulls and cows.