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An evaluation of methods for improving reproductive performance in summer lambing ewes

Published online by Cambridge University Press:  24 November 2017

E King Margaret
Affiliation:
The North of Scotland College of Agriculture , 581 King Street, Aberdeen, AB9 1UD
L M Mitchell
Affiliation:
The North of Scotland College of Agriculture , 581 King Street, Aberdeen, AB9 1UD
J S M Hutchinson
Affiliation:
School of Agriculture, University of Aberdeen 581 King Street, Aberdeen AB9 1UD
R Glatt
Affiliation:
School of Agriculture, University of Aberdeen 581 King Street, Aberdeen AB9 1UD
M F Ibraheem
Affiliation:
School of Agriculture, University of Aberdeen 581 King Street, Aberdeen AB9 1UD
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Extract

Manipulation of seasonality in the ewe has been the subject of extensive research over the past few years. Demand for continuous supply of home-bred lamb has encouraged producers to breed their ewes both earlier and later in their natural breeding season. Extending the breeding season to a Summer (May/June) lambing has proved a low input system reducing the requirement for concentrate feeding in late pregnancy and eliminating the need for housing during the winter period (Stone, 1988). However, Summer lambing involves mating ewes in January when fecundity may be declining. Exogenous Melatonin has been shown to be effective in advancing the breeding season by extending the length of time that significant levels of Melatonin are present in the blood. It may also have a beneficial effect on embryo survival (Wigzell et al, 1986; Kennaway et al, 1987). In Summer lambing ewes, where endogenous Melatonin is in decline during tupping in January, the introduction of exogenous Melatonin may result in continued reproductive activity and aid implantation of embryos.

Type
Sheep Production
Copyright
Copyright © The British Society of Animal Production 1990

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References

Kennaway, D. J., Dunstan, E. A. and Staples, L. D. (1987) Photoperiodic control of the onset of breeding activity and fecundity in ewes. J. Reprod. Fert. Suppl. 34:187199.Google Scholar
Stone, C. R. (1988) The Management and Performance of a Flock lambed in May. Anim. Prod. 46:511 (Abst.).Google Scholar
Wigzell, S., Robinson, J. J. Aitken, R. P., and McKelvey, W. A. C. (1986) The effect of the oral administration of Melatonin at two times of the year on ovarian activity in ewes. Anim. Prod. 42:448449.Google Scholar