Techniques and success of embryo transfers in Angora goats.
Thirty-five mixed-age Angora does were subjected to superovulation and oestrous synchronization and of the 34 which were subsequently entire mated, 33 were subjected to surgical egg recovery approximately five days after oestrus. These 33 donors averaged 8.8 ovulations and 2.5 large (>5 mm) follicles. All corpora lutea in six donors were undergoing premature regression. The average donor egg recovery rate, egg fertilization rate and percent of eggs transferable was 82,87 and 81%, respectively, giving 6.8 eggs, 6.0 embryos and 5.5 transferable embryos per donor. Egg recovery was reduced dramatically when premature regressing corpora lutea were present. Recipient feral does were synchronized and 183 embryos transferred surgically to 133 recipients. Eighty-eight (66%) of the recipients kidded producing 118 kids (64% embryo survival). The 35 potential donors produced 36 kids from their natural mating which occurred shortly after surgery. Thus the donors produced a total of 154 kids from embryo transfer and natural mating, an average of 4.4 kids/doe/breeding season. This rate of reproduction is four to five times faster than normal and confirms that the technique achieves its objective of rapidly increasing the number of offspring from selected animals.
Tervit
H R
HR
Ruakura Animal Research Station, Private Bag, Hamilton.
Goold
P G
PG
McKenzie
R D
RD
Clarkson
D J
DJ