Multiple mating and siring success during natural oestrus in the ewe.
Ewes were each mated on four separate occasions, at 3, 9, 15 and 21 h after the start of oestrus and at each time by a different ram. The progeny were assigned to sires by blood typing, supplemented by resemblance between lambs and rams. The paternity of 64 lambs, born to 41 ewes, was established: 2 were conceived at a 3-h mating, 27 at 9h, 23 at 15 h and 12 at 21 h. The optimum time for a ram to inseminate, when in competition with others, is therefore 9-15 h after onset of oestrus, and this finding accords with behavioural observations. Ewes tended to lamb during the same half of the day as that when they had come into oestrus.
D000818:Animals; D001788:Blood Grouping and Crossmatching / Q000662:veterinary; D003307:Copulation; D004971:Estrus; D004972:Estrus Detection; D005260:Female; D007743:Labor, Obstetric; D008098:Litter Size; D010334:Paternity; D011247:Pregnancy; D012744:Sex Ratio; D012756:Sheep / Q000502:physiology*; D013997:Time Factors