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A note on the effect of zeranol administration on oestrous cycle length and hormonal profiles in cows

Published online by Cambridge University Press:  02 September 2010

W. E. Beal
Affiliation:
Animal Science Department, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061, USA
G. A. Good
Affiliation:
Animal Science Department, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061, USA
D. J. Putney
Affiliation:
Animal Science Department, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061, USA
G. L. Johnson
Affiliation:
Animal Science Department, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061, USA
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Abstract

Zeranol is an anabolic agent with oestrogenic actions commonly used in fattening beef cattle. This experiment was designed to determine the effects of zeranol administration on oestrous cycle lengths, plasma progesterone concentrations and the exhibition of oestrus in mature cows. Administration of 36-mg zeranol implants during the early, middle or later portion of the oestrous cycle did not alter the length or persistence of oestrous cycles, nor were progesterone profiles different from those observed in untreated cows. Some cows that received zeranol exhibited a prolonged oestrus. The regularity of oestrous cycles in cows treated with zeranol indicates that it may be possible to utilize zeranol as an anabolic and lactopoetic agent in post-partum beef cows.

Type
Research Article
Copyright
Copyright © British Society of Animal Science 1986

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References

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