Abstract
A total of 1924 milk yield records and 1523 birth weight records from progeny arising from 59 sires and 359 dams were studied. The heritabilities of 120 day mean milk yields among Local Indian Dairy (LID), Red Sindhi (RS), ½ LID ½ RS , and ¼ LID ¾ RS cattle were 0·17±0·33, 0·21 ±0·63, 0·04±0·11 and 0·08 ± 0·10 respectively by variance component analysis. The corres-ponding values by the daughter-dam regression method were 0·27 ± 0·20, 0·61±0·77, 0·56±0·21 and 0·37±0·14. The estimates by both metl10ds fluctuated alternately in successive lactations. Heritability of mean birth weight by variance component analysis was 0·84 ± 0·60, 0·28 ± 0·10 and 0·25 ± 0·18 for Red Sindhi, ½ LID ½ RS and ¼ LID ¾ RS cattle respectively. The estimates by the daughter-dam regression method for the last two groups of cattle were 0·23 ± 0·31 and 0·35 ± 0·30 respectively.
