Hostname: page-component-84b7d79bbc-2l2gl Total loading time: 0 Render date: 2024-07-28T00:07:59.105Z Has data issue: false hasContentIssue false
  • English
  • Français

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
Get access

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

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Fulkerson, W. J.,Adams, N. R. and Gherardi, P.B. (1981). Ability of castrate male sheep treated with oestrogen or testosterone to induce and detect oestrus in ewes. Appl. Anim. Ethol. 7: 57–66.Google Scholar
Martin, G.B., Congnie, Y., Schirar, A., Ribeiro, A.N., Nys, C. F. and Thiery, J. C. (1985) Diurnal variation in the response of anoestrous ewes to the ram effect. J. Reprod. Fertil. 19: 869–875.Google Scholar
Oldham, C.M. and Martin, G. B. (1979). Stimulation of seasonally anovular Merino ewes by rams. 2. Premature regreesion of ram-induced corpora lutea. Anim. Reprod. Soi. 1: 291–295.Google Scholar
Oldham, C. M., Pearce, D. T. and Gray, S. J. (1985). Progesterone priming and age of ewe affect the life-span of corpora lutea induced in the seasonally anovulatory Merino ewe by the ram effect. J. Reprod. Fertil. 75: 29–32.Google Scholar
Signoret, J. P., Fulkerson, W. J. and Lindsay, D. R. (1982). Effectiveness of testosterone treated wethers and ewes as teasers. Appl. Anim. Ethol. 9: 37–45.Google Scholar