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Observations on the reproductive activity of tropical sheep in relation to the photoperiod

Published online by Cambridge University Press:  27 March 2009

R. B. Symington  and
J. Oliver
R. B. Symington
Affiliation:
Department of Agriculture, University College of Rhodesia and Nyasaland, Salisbury, Rhodesia
J. Oliver
Affiliation:
Department of Agriculture, University College of Rhodesia and Nyasaland, Salisbury, Rhodesia
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Extract

A study has been made of the effect of a progressive increase in the hours of light each day on the sexual activity of German Merino, Persian Blackhead and indigenous ‘Native’ ewes.

Incidence of oestrous tended to be greater in ewes subjected to extended daylight than in ewes subjected to the natural photoperiod. This was particularly true during the latter stages of the study. Duration of oestrus was unaffected by the extended daylight but varied temporarily in both groups of ewes. The effect of extended daylight on duration of the oestrous cycle and on the incidence of oestrous cycles of normal or abnormal duration was not marked and differed between breeds. Extension of daylight to 19 hr. each day apparently did not prevent reproduction since several light-treated ewes inadvertently conceived, gave birth to and reared a healthy lamb after a gestation period of normal length.

Type
Research Article
Information
The Journal of Agricultural Science , Volume 67 , Issue 1 , August 1966 , pp. 7 - 12
Copyright
Copyright © Cambridge University Press 1966

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