STUDIES ON GENETIC PARAMETERS OF AGE AT FIRST CONCEPTION IN HOLSTEIN x SAHIWAL CROSSBRED

摘要

Data on 1017 Holstein X Sahiwal crossbreds from three military dairy farms were collected and analysed. The overall least squares mean lor the trait was 672.30±11.77 days. The least square analysis of variance showed that the effects of farm, periodof birth, genetic group and partial regression of 12 months and 18 months body weight had highly significant effect on age at first conception. The results indicated that a sufficient lower age at first conception was obtained with the Holstein inheritance upto 5/8th. The beritability estimate of the trait was 0.54±0.12. Lower age at first conception could he obtained by selecting the animals with higher birth weight. The reduced age at first conception is associated with lower age at first calving, higher first lactation milk yield, 300 days milk yield and first four cummulative milk yield and lifetime performance of dairy animal.