Abstract

Castrate male and female lambs (n=8) received no treatment (O dose) or a silicone rubber implant containing 3 mg (L dose), 22 mg (M dose) or 52 mg (H dose) of oestradiol, respectively. Implants were placed subcutaneously at 8-10 weeks of age (mean weight 20.4 kg) and the animals slaughtered 180 d later. Oestradiol treatment decreased length of cannon bone but increased length of vertebral column and 12th rib. Cessation of growth in an early maturing bone (cannon bone) appeared to be accelerated by the treatment so that length was reduced. Later maturing bones (rib and vertebrae) showed a dose-dependent stimulation of linear growth. It is concluded that oestrogens accelerate the natural process of skeletal maturation.

WH, McMillan

Proceedings of the New Zealand Society of Animal Production, Volume 47, , 151-154, 1987