New Zealand Journal of Agricultural Research abstracts

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Effects of oestradiol implants on musculo-skeletal growth of wether and ewe lambs

O. MAHGOUB*
G. K. BARRELL⁺

Animal and Food Sciences Division
P.O. Box 84
Lincoln University
Canterbury, New Zealand

J. J. BASS

AgResearch
Ruakura Agricultural Centre
Private Bag 3123
Hamilton, New Zealand

*Present address: Department of Animal and Veterinary Sciences, College of Agriculture, Sultan Qaboos University, P.O. Box 34, Al Khod 123, Sultanate of Oman.

Abstract  Oestrogenic growth promotants stimulate lean carcass growth and reduce carcass fat in livestock but little is known about their actions on musculo-skeletal growth per se. To investigate such effects, selected bones and muscles were measured in castrated male and entire ewe lambs treated from 4 weeks of age with implants containing oestradiol-17β. Half of the animals were slaughtered at 14 weeks and half at 23 weeks of age. Oestradiol treatment significantly stimulated the linear growth of vertebrae, with the effect being most pronounced in ewe lambs slaughtered at 14 weeks. The treatment also increased the diameter of some limb bones and slightly increased the length and girth of attached muscles. Castrated male lambs tended to have longer bones and longer and heavier muscles than entire ewes. This study showed that, in sheep, oestrogens cause a short-term increase in length in growing bones.

Keywords  sheep; bone growth; muscle growth; oestrogens

New Zealand Journal of Agricultural Research, 2001, Vol. 44: 37-46

0028-8233/01/4401-0037 $7.00/0 (c) The Royal Society of New Zealand 2001

PDF file of entire paper: medium quality (623K); (scanned from paper original: notes about this process)

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