Department of Livestock Production and Management, College of Veterinary Science, Assam Agricultural University, Khanapara, Guwahati-781 022, India.
Corresponding author, Present address: Cattle Research Station, SKUAST-K, Manasbal, J&K, email: drjakir@gmail.com
*Part of M.V. Sc. thesis submitted by first author
The least square means of age at first calving for Jersey X Local, Holstein Friesian X Local and Local cattle of Assam under field condition were 36.526 ± 0.576, 39.972 ± 0.641 and 46.719 ± 0.674 months, respectively. Effect of genetic group on this trait was highly significant (p<0.01). The Jersey X Local cows had significantly lowest age at first calving than Holstein Friesian X Local and Local cows. The effect of season of birth on age at first calving was also highly significant (p<0.01). Cows born in summer monsoon (March to May) and South West monsoon (June to September) seasons had significantly longer age at first calving than those born in post monsoon (October to November) and winter (December to February) seasons.
Age at first calving, Jersey cross, Holstein Friesian cross
