New Zealand Journal of Agricultural Research abstracts
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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