Abstract

Most sheep breeds experiences period of reduced sexual activity during the hot summer months. In some breeds this activity can halt completely and the ewe starts a period of aneostrus. Using light control and/or hormone treatment were found to be effective in controlling the reproductive processes during this infertile period (Ducker, Thwaites and Bowman, 1970; Rommel, Muller and Elze, 1978; Hamilton and Lishman, 1979; Walton, Evins, Fitzgerald and Cunningham, 1980). DLS is a pupulation of sheep presently being developed in Quebec for extended breeding season (Fahmy, 1976, Fahmy, MacIntyre and Chancey, 1980). The animals are selected from a population of J Dorset, l Leicester and 4 Suffolk for their ability to mate during the summer months. They are exposed to rams on June 1st each year and their lambing date recorded. The rams born to the early-lambing ewes are those used for breeding. An unselected control population was maintained to assess the genetic changes occurring in the selected group. The rams in this control population were chosen at random. The objective of this study is to report on the ovulation observed from May to September in the selected as compared to the control group.

M. H Fahmy

Proceedings of the World Congress on Genetics Applied to Livestock Production, Volume 7. Symposia (1), , 474–478, 1982
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