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Stimulation of seasonally anovular mule ewes by rams

Published online by Cambridge University Press:  22 November 2017

H. F. Ibraheem ,
M. E. King ,
J. S. M. Hutchinson ,
G. J. Gunn ,
L. Taylor  and
T. Atkinson
H. F. Ibraheem
Affiliation:
School of Agriculture, University of Aberdeen , 581 King Street, Aberdeen AB9 1UD
M. E. King
Affiliation:
School of Agriculture, University of Aberdeen , 581 King Street, Aberdeen AB9 1UD
J. S. M. Hutchinson
Affiliation:
School of Agriculture, University of Aberdeen , 581 King Street, Aberdeen AB9 1UD
G. J. Gunn
Affiliation:
School of Agriculture, University of Aberdeen , 581 King Street, Aberdeen AB9 1UD
L. Taylor
Affiliation:
School of Agriculture, University of Aberdeen , 581 King Street, Aberdeen AB9 1UD
T. Atkinson
Affiliation:
Rowett Research Institute, Bucksburn, Aberdeen
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Extract

Early lamb production is a specialist enterprise in which profitability is highly dependent on getting all the lambs sold while prices are still high in Spring when lamb is in short supply. This involves lambing in late December/early January. Hence ewes must be mated in August. Conventionally in the UK, this has been achieved by the use of progesterone-impregnated sponges and pregnant mare's serum gonadotropin (PMSG). The ram effect is a powerful technique for the control of sheep reproduction. The objective of the present study was to reinvestigate the value of teasers for the stimulation of seasonal activity in the ewe.

125 (2-3 yr) Mule ewes (Blue-faced Leicester x Swaledale or Blackface), isolated from rams for two months, were used to investigate the effect of different durations of teasing on the stimulation of seasonal activity. Groups of 25 ewes were exposed to either teaser vasectomised rams and teaser ovariectomised ewes (induced into behavioural oestrus by an intramuscular injection of 0.2 mg of oestradiol benzoate) for 1 month (group l), 3 weeks (group 2) and 2 weeks (group 3); or vasectomised rams only for 2 weeks (group4); or left untreated (group 5). At the imposition of treatments, groups were isolated from each other and from contact with other 3heep by a distance of at least 1 km. Plasma progesterone was measured twice weekly on 8 animals, per group to determine ovarian activity.

Type
Production and Management of Small Ruminants
Information
Proceedings of the British Society of Animal Production (1972) , Volume 1989 , March 1989 , pp. 57
Copyright
Copyright © British Society of Animal Production 1989

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References

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