Superovulation with ova transfer (1979, 1980) and superovulation (without ova transfer) plus artificial rearing (1981, 1982) were used to establish flocks of Romney, Perendale and Coopworth sheep from fecund animals donated by farmers. In their first and second years respectively in the ova transfer programme, 39% and 32% of donor ewes failed to have any progeny by ova transfer, and 38% and 44% failed to lamb themselves while the mean number of lambs tailed per donor at joining was 2.68 and 2.21. In their first and second years respectively in the artificial rearing programme only 7% and 3% of ewes failed to produce a lamb with a mean number of lambs born per donor joined of 2.15 and 2.36. High lamb mortality rates (27% and 32% of lambs born) resulted in 1.58 and 1.64 lambs tailed/ewe/annum. About 40% of ewes failed to reach the objective of at least 2 live lambs/ewe/annum in both programmes.
Proceedings of the New Zealand Society of Animal Production, Volume 43, , 197-200, 1983
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