Heritabilties and Breeding Values of Production and Reproduction Traits of Holstein Cattle In Iraq


A total of 4714 records collected from 733 cows progeny of 13 sires through the period from 1989 to 2000 in Al-Nassr Dairy Cattle Station were used to estimate the heritability and breeding values of sires for total milk yield, days in milk, calving interval, dry period and age at first calving. Individual animal models were fitted to the total milk yield from all lactations to estimate breeding values by Restricted Maximum Likelihood methodology. Heritability was estimated by using different methodology. Their values for milk yield, days in milk and dry period, calving interval and age at first calving were (0.05-0.21), (0.02-0.09), (0.32-1.00), (0.00-0.23) and (0.36-0.43) respectively. The estimated breeding values for milk yield ranged from –394.00 to 475.00 kg. Estimates of the positive breeding value (BV, %) was 48.56 %. Breeding values of days in milk ranged from -5.44 to 6.30 days and 45.48% respectively. However, sires showed lower (23%) positive breeding value for both dry period and calving interval and age at first calving (30%). Their breeding values ranged from -15.95 to 49.60 days for dry period, -8.14 to 11.91days for calving interval and -2.10 to 2.28 months for age at first calving.