Abstract

Trials between 1979 and 1984 with Angora or Saanen donors showed that synchronisation of oestrus with progesterone injections delayed oestrus compared with progestagen sponges and that this delay was associated with fewer follicles and increased egg recovery and fertilisation rates. Highest ovulation rates were achieved when FSH was injected instead of PMSG and when donors were Saanens rather than Angoras. Surgical egg recovery rates decreased in donors with prematurely regressing ovulations. The response of recipients (feral or Angora) to sponge treatment varied markedly between years. Recipient pregnancy rate and embryo survival both increased when recipients were surgically twinned rather than singled. The various trials have enabled the development of an effective transfer regime. This involves synchronising/superovulating donors with progesterone/FSH and twinning or tripleting of recipients. Under these conditions Angora and Saanen donors average respectively, 14.0 and 24.5 ovulations, 10.8 and 18.6 transferable embryos and 7.5 and 11.8 kids born to recipients.

H, Hawker, and RP Littlejohn

Proceedings of the New Zealand Society of Animal Production, Volume 46, , 219-224, 1986