Effects of Breed of Sire, Percentage of Bos Taurus Inheritance and Season of Birth on Calving Performance of Crossbred Dairy Cattle

Data collected from crossbred dairy cattle at the Institut Haiwan, Kluang, were used to evaluate the effects of breed of sire, percentage of Bos taurus inheritance and season of birth on some calving traits. Breed of sire effect was significant on age at first service (p < 0.01), age at first calving (p < 0.01) and postpartum interval to first service (p < 0.05) but not on calving interval (p > 0.05). Linear contrasts indicate that crossbred-sired cows had first service 593 days earlier and first calving 508 days earlier than purebred-sired cows. Cows sired by Friesians, however, had the earliest first service (466 days) and were among the earliest at first calving (917 days). However, the crossbred-sired cows had slightly longer post-partum interval to first service (13 days longer) and calving interval (20 days longer). Percentage of B. taurus inheritance affected (p < 0.01) all the calving traits studied. In general, the cows with 50% inheritance had the best calving performance. Season of birth had no effect (p > 0.05) on them.