Effect of pre-calving liveweight gain of Angus heifers calving at two years of age on their subsequent milk yield and calf growth rate

Abstract

On 14 March 1978, 22 Angus heifers due to start calving in July 1978 when they were two years of age, were randomly allocated to one of two nutritional groups under pasture grazing management. The heifers on treatment TS (treatment steady) were fed to maintain a steady liveweight gain of 0.3 kg/day until calving commenced on 17 July 1978. The heifers on treatment THC (treatment high constant) were fed to allow a liveweight gain of 0.6 kg/day until 7 weeks before calving began, and then fed to maintain constant liveweight until calving commenced on 17 July 1978. At the start of calving, the heifers in both treatment groups had approximately the same mean liveweight, namely, TS 374 kg and THC 376 kg. A significant (P < 0.005) effect favouring the TS treatment was observed on a combination of calf birth weight and weight of milk consumed. However, calf liveweight showed little evidence of treatment influence 130 days after calving began, which was therefore considered to be of no commercial importance. The nutritional treatments did not affect the calving percentage or the calving date of the females in the following year.

Keywords:

• heifers
• calves
• Angus
• nutrition
• liveweight gain
• milk yield