Proceedings of the New Zealand Society of Animal Production.
1992, 52: 187-190
Proceedings of the New Zealand Society of Animal Production.
1992, 52: 187-190
From birth to 16 months of age, the pattern of liveweight gain in the early-born and control calves was similar, but because of the 6 week advance in calving, early males and females were on average 11 to 13 kg heavier at weaning on February 22, and 10 kg heavier than their control counterparts one year later.
Pedicle initiation in males and plasma progesterone patterns in females were monitored to determine the stage of sexual development. Early-born male calves attained a pedicle height of 1.5 cm on 30 June at 250 d of age and an average liveweight of 71.1 kg. The control calves initiated pedicles 55 d later (24 August, SED ± 12.6 d, P<0.01) at a similar age (264 d, SED ± 12.4 d, NS) but at a significantly lower liveweight (66.1, SED ± 1.6 kg, P<0.05). No female calves (early born or control) showed signs of ovarian cyclicity in plasma progesterone during the normal breeding season for adult hinds. Average liveweights on 23 April were 61.6 ± 4.5 and 49.2 ± 0.4 kg for the early and control female calves respectively.
Although early calving resulted in enhanced liveweights, only 2 of the hind calves reached 65kg, the lower threshold liveweight required for the attainment of puberty in yearling hinds, and none displayed ovarian activity indicative of puberty. In contrast to the situation with the hind calves where there was no evidence of precocious puberty, the early-born calves initiated pedicles earlier than the controls and two of them had developed hard antlers (evidence of precocious puberty) by October 1.
Keywords: NZSAPAB; Red deer; Cervus elaphus birth; growth; liveweight; puberty; antler pedicle.
