Hormonal synchronization of oestrus in Romney ewes during the breeding season

J.N. Clarke, E.M. Roberts, A.H. Carter and A.H. Kirton

Ruakura Agricultural Research Centre, Ruakura

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Proceedings of the New Zealand Society of Animal Production. 1966, 26: 107-122

The experimental flock comprised 24 balanced single-sire mating groups each of 27 mature Romney ewes. Representative samples of 7 to 9 ewes from each group were treated for 13 days with intravagina1 sponges containing 60mg 6alpha-methyl-17alpha-acetoxyprogesterone (MAP). Nine of the groups were mated with ram hoggets, the remaining 15 with two-tooth rams (18 to 20 months).

Among the older ram groups, 89% of the treated animals were marked over a &day period following sponge withdrawal, and 64% of these ewes lambed to matings at this time. Corresponding mean figures were 59% and 44% for the ram hoggets, which exhibited much greater

Keywords: NZSAPAB;

Last Updated 24-08-2000