REPRODUCTIVE PERFORMANCE OF HOLSTEIN HALFBRED AND JERSEY HALFBRED COWS IN THE PLAINS OF EASTERN INDIA

Abstract

The data on the reproductive traits of 44 Jersey Halfbreds and 23 Holstein Halfbreds in their first parity, born during the period 1977-96 at the Institute Farm were analyzed by least squares technique for the effect of genetic and non-genetic factors on reproduction traits viz. age at first calving, weight at first calving, service period, inter-calving period and number of inseminations required per conception. The difference between the two genotypes was significant (P<0.05) with respect to age at first calving only. Jersey Halfbreds had lower age at first calving (1063.6+19.1 days) than the Holstein Halfbreds (1160.5+27.5) days). Period of calving significantly affected age at first calving, while season of calving had no significant effect on any of the traits. Service period had significant and positive correlation with Inter-calving period (0.85) and number of inseminations per conception (0.30), while inter-calving period had a negative correlation (0.24) with the latter. The study implies that there is scope of further reduction in the service period and inter-calving period through better artificial insemination management.