Abstract

Approximately 72% of New Zealand dairy cows are artificially mated to generate replacement heifers. There is an opportunity to mate the remaining dairy cows to beef bulls, generating a calf that has value as a beef-cross-dairy animal. Angus and Hereford are the predominant beef breeds in New Zealand, with Hereford the most common beef breed used in the dairy industry. The aim of this experiment was to determine whether there was a difference in milk production and rebreeding performance of mixed-aged dairy cows producing a calf sired by an Angus or Hereford bull, and if calf birth weight influenced these parameters. Cows were artificially bred to Angus or Hereford bulls. Service sire-breed had no effect on milk production in early lactation. Cows producing Angus-sired calves had a 2.4 kg greater 253-day protein yield (P<0.05) than did cows producing Hereford-sired calves, however, there was no effect of calf sire-breed on the 253-day yields of milk, fat and milksolids. The in-calf rate and inter-calving interval did not differ between service sire-breed. There was no effect of calf birth weight on milk production, in-calf rate or inter-calving interval. The results of this experiment suggest that there are no negative effects associated with artificially breeding cows to Angus compared to Hereford bulls.

LW, Coleman, PJ Back, HT Blair, N Lopez-villalobos, and RE Hickson

New Zealand Journal of Animal Science and Production, Volume 79, Palmerston North, 144-148, 2019