Stimulation of Ovulation in Seasonally or Lactationally Anovular Ewes by Rams
نویسندگان
چکیده
If preconditioned by a period of isolation from rams during the non-breeding season, ewes of many breeds respond to the reintroduction of rams (teasing) by displaying a relatively synchronised oestrus, approximately one oestrous cycle later (Merino: Schinckel 1954a; Awassi: Eyal 1958; Romney: Edgar and Bilkey 1963; Merinos d'Arles: Prud'hon et al. 1966). The oestrous activity of the flock is spread over approximately 10 days but characteristically with two peaks: the first around day 18, and the second around day 24 after teasing. In successfully teased ewes the first oestrus is preceded by a silent ovulation (ovulation without oestrus) within six days of the introduction of rams (Schinckel 1954b). Progesterone priming is necessary if behavioural oestrus is to accompany the raminduced ovulation (Hunter et al. 1971).
منابع مشابه
Can the "ram Effect", or the "ram Effect" plus Pmsg Be Used to Advance the Breeding Season of Southdown Ewes?
The 'ram effect' induced some seasonally anovular Southdown ewes (23%) to ovulate within 5 days of introducing Southdown rams on 10 December. Priming the ewes with medroxy progesterone acetate from intravaginal sponges for 12 days, immediately before the introduction of the rams, ensured that most of the ewes displayed oestrus at the ram-induced ovulation. The proportion of anovular ewes ovulat...
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