Precalving nutrition of heavy two year old Angus heifers weighing 415 kg at calving

A.B. Pleasants, R.A. Barton

AgResearch, Whatawhata Research Centre, Private Bag 3089, Hamilton, New Zealand

Proceedings of the New Zealand Society of Animal Production. 1992, 52: 303-306

When they were weaned at five and a half months of age, 33 Angus heifers were randomly divided into two groups representing different planes of nutrition. From weaning until two months before calving which began on 15 July 1977 the liveweight difference between the two groups was steadily increased until the high plane group (HP) weighed 17 kg more than the low plane group (LP) on 17 May 1977. From then until calving the high plane group was fed to maintain constant liveweight, while the low plane group was fed to gain liveweight at the rate of 0.3 kg/day. When calving began both groups weighed the same average liveweight (415 kg).

Calf birth weight was affected by nutritional treatment (HP 26.2 ± 0.65; LP 28.1 ± 0.54; P<0.05), as was the degree of calving difficulty (HP 0%; LP 24%; P<0.05). Calf milk consumption, calf liveweight gain, calf weaning weight and reproductive performance of the heifer were not affected by plane of nutrition.

The regression of the post-partum anoestrous interval on calving date was -1.88 ± 0.474 days/day (P<0.01). All variance in this relationship was accounted for by the covariance between post-partum anoestrus interval and the other response variables measured, suggesting that a common factor might be operating.

The results suggest that liveweight gain close to calving in well fed Angus heifers weighing in excess of 400 kg is associated with increased calving difficulty and should be avoided.

Keywords: NZSAPAB; Angus heifers; two year old; calving; heavy liveweight.

Download abstract in text format
Last Updated 25-01-1997