Effects of different rates of liveweight change from 60 days before calving to calving on the productivity of mature Angus breeding cows

Abstract

Abstract A herd of 55 Angus breeding cows aged 5–9 years were randomly allocated to two nutritional treatments 50 days before calving commenced in the herd. At this stage the cows had lost 8% of their autumn liveweight (22 April) of 470 kg to weigh an average of 443 kg. One group (HP) maintained its liveweight until 30 days before calving commenced. The second group (LP) continued to lose liveweight until 30 days before calving commenced. At this stage the HP weighed 438 kg and the LP weighed 426 kg. Both groups were then run together through calving on sufficient pasture to allow liveweight gains of 0.3–0.5 kg liveweight/day. Pre-calving nutritional treatments had no significant effect on any of the dependent variables (i.e., calf birth weight, calf liveweight at c. 20, 40, and 60 days of age, cow milk production at c. 20, 40, and 60 days after calving, and the length of the post-partum anoestrous interval). Date of calving had a significant (P < 0.01) effect on calf liveweight measured at 20, 40, and 60...