Data on performance records of 1249 Frieswal daughters of 71 sires over a period of 13 years from 2000-2012 were analyzed to determine the effects of farm, parity, type of calving, period of birth and season of birth on lactation length (LL), 305-day milk yield (305-DY) and calving interval (CI). The age at first calving (AFC) was considered as covariable. The overall least-squares means for AFC, LL, 305-DY and CI were 31.45±0.89 months, 303.31 ± 7.02 days, 2997.01 ± 123.24 kg and 431.19 ± 16.53 days respectively. Period of birth had significant effect on age at first calving. Farm, type of calving and period of birth had significant effect on lactation length. Farm, parity and season of birth had significant effect on 305-day milk yield. Parity, type of calving, period of birth and season of birth had significant effect on calving interval. Heritability estimates for LL and CI were low (0.17 ± 0.10 and 0.11 ± 0.09), while it was high (0.51±0.14) for 305-DY. The phenotypic and genetic correlation between lactation length, 305-day milk yield and calving interval were observed high and positive.
Frieswal Cattle;Least-Squares;Heritability;Genetic and Phenotypic Correlation