The Sensitivity of Ovarian and Oestrous Activity in Southdown Ewes to an Intramuscular Injection of Pregnant Mare Serum Gonadotrophin
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چکیده
A group of Southdown ewes (n=lll), two years and older, which had been maintained in isolation from rams had intravaginal sponges (Repromap, Upjohn) inserted on 18 Dee (day 0). On day 10 after sponge insertion rams (10%) were introduced to the ewes and at sponge withdrawal on day 12 they were harnessed and the ewes were allocated at random to PMSG treatment. The doses of PMSG were 0, 100, 200, 250, 300 or 350 iu, given as a single intramuscular injection. The PMSG had been previously standardised in a rat testis bioassay against a purified standard (Folligon, Intervet). Ovarian activity of the ewes was assessed'by laparoscopy on day 18. Treatment effects were tested by analysis of variance.
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Can the "ram Effect", or the "ram Effect" plus Pmsg Be Used to Advance the Breeding Season of Southdown Ewes?
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