Abstract

As part of a programme to increase the number of homozygous (FecB FecB) replacements available in the Booroola Merino flock at the Tara Hills Research Station a MOET technique was utilised. Because ewes of BB genotype are difficult to superovulate, with predictable results, using conventional treatment regimes, a simplified programme aimed at enhancing the natural ovulation rate was used. Thirty eight ewes were treated for 10-11 days with intravaginal sponges. The ewes were then injected with 500 iu of PMSG on day 15 after sponge withdrawal and joined with entire rams for 5 days. Sixty six percent of ewes were marked by the ram and the mean ovulation rate of these was 8.3 (range 5- 18). Embryo recovery rate was 93.4% following retrograde flushing of the fallopian tubes. Fertilisation rate was 68% and 5.3 embryos were transferred per donor operated (range 0.-11). The ewes were remated and lambed naturally. By using a combination of MOET and remating, 24 donor ewes produced a mean of 3.3 lambs weaned compared to 1.4 lambs weaned by their naturally mated flock mates.

GH, Shackell

Proceedings of the New Zealand Society of Animal Production, Volume 51, , 73-78, 1991