Egg transfer results up to world standards

Press, Volume CXIV, Issue 33513, 19 April 1974, Page 9

Egg transfer results up to world standards

There is evidence that in the advanced technique of transferring fertilised eggs between female cattle — known as ova or egg transplants — New Zealand veterinarians are achieving results as good as anvwhere in the world.

Over the Christmas period veterinarians employed by Southern Breeders Ltd. in Southland, transferred 36 eggs from six females with 20 recipients being confirmed m calf under pregnancy test—a 55 to 56 ner cent success rate.

Three weeks ago this Southern Breeders team conducted a series of transplant operations for Kaiapoi Transplants at their Kaiapoi laboratories.

In December an Australian team from Australian Transplant Breeders consisting of Dr James Shelton and Professor N. Moore carried out a series of operations at Kaiapoi in which they transferred 36 eggs from nine donor cows and achieved 17 positive pregnancies in the recipients—almost a 50 per cent success.

Mr R. G. Macdonald, of Kaiapoi Transplants, said that these were very com-

petent and knowledgeable people and he had been extremely satisfied with them, but they would not be carrying out further operations at his laboratory.

The Southern Breeders team consists of Mr D. Marshall, of Otautau, and Mr G. A. Struthers, of Winton, veterinarians in their districts, and an anaesthetist. Three weeks ago they transferred 61 eggs from 11 cows.

Southern Breeders Ltd, is a group of 10 South Island farmers who have joined together to breed and market exotic cattle. Mr H. R. Irving. a spokesman for the group, which owns a considerable number of exotic purebred cattle, said that they saw in developing the egg transfer technique the opportunity to expand the number of these purebred cattle.

But the approach of his group to the development

of the technique was very much that the multiplication of valuable exotic cattle was only “the short term spectacular” of the process. They hoped to use it in the longer term as a tool of cattle breeding to take advantage of superior animals within breeds as research work made it more reliable.

Mr Irving said that the work of Southern Breeders in this field had begun in March last year and been continued ever since on an intensive basis. The first transfer of eggs from a purebred exotic donor had been made on July 28 with two positive pregnancies resulting from eight egg transplants. During the July to Christmas period the success rate of eggs transplanted to positive pregnancies had averaged about 25 per cent, giving 11 confirmed pregnancies of purebred Limousins and Simmentals.

At this stage the group had realised the need for some radical changes in techniques and in a series of operations at Christmas time 36 eggs from six FI Simmentals had been transplanted with 20 (55 to 56 per cent), pregnancies being confirmed.

Mr Irving said that the results from the individual donor females had been — No. 1: four eggs transplanted with one positive pregnancy. No. 2: eight eggs transplanted and six pregnancies. No. 3: 10 eggs transplanted with seven pregnancies. No. 4: five eggs transplanted with one positive pregnancy test. No. 5: nine eggs transplanted with five positive pregnancies. No. 6: one egg transferred but no positive test. In summary, Mr Irving said that the results from some donor cows had been extremely good but others had not done so well. The Southern Breeders team, he said, had developed an advanced technique for flushing eggs from donors but they could still see room for improvement in egg lecovery by better handling techniques and they anticipated improving further on the results achieved at Christmas time.

But the group was satisfied with their level of achievement in that it closely paralleled the most successful work overseas.

Overseas, he said, it was considered good to

obtain six fertilised eggs per donor cow and to obtain a positive pregnancy test from 60 per cent of the eggs transplanted. Mr Irving said that their group had close working relationships with groups working in this field throughout the world. In the operations at Kaiapoi three weeks ago one cow produced 28 eggs —the biggest number of eggs from a single animal — but only one appeared to be fertilised and this was doubtful. This, however, was outside the control of the operating team in that it was directly attributable to the quality of the semen used. Another South Island group is also working with the technique, but results of their work are not available at this stage. An expert in this field, Dr Robin Tervit, a scientist at the Ruakura agricultural research centre, who spent three years at Cambridge in England where basic research work was done on the technique, and who has done a large number of egg transfers himself, confirms that some of the results being obtained in New Zealand are comparable with those being obtained by commercial organisations overseas.