Panel on embryo transplanting

Press, 13 April 1984, Page 29

Panel on embryo transplanting

Embryo transplanting in cattle can be a useful means of increasing productivity rates, yet it is expensive and has its limitations.

This was the message that came from a panel discussion on the technique, practice and concerns of embryo transplanting at a session of the Ninth World Hereford Cattle Breeders Conference in Christchurch recently. Members of a four-person international panel spoke individually on the topic, and then answered questions from the floor. The panel was chaired by Mr Charles Scranton, president of the Canadian Hereford Association.

Mr Alexander Ferguson, a director of Genestock (N.Z.), Ltd, engaged in embryo transplanting, said the method had been used on a large scale since 1978. “Demand at the beginning was marked by the sort of enthusiasm found in a space programme,” he said.

Initial failures were mainly due to a lack of understanding of the limitations of the method, he said.

“We are now in phase two.” The best application of the method required a lot of breeder involvement, using at least 10 good breeding age females because of variability. “If just the top females are used it can lead to being a very costly exercise,” he said.

Mr Ferguson said he was working in miniaturising cattle for delivery embryos to underdeveloped countries. He was also involved in embryo splitting, and in sexing embryos when seven days old. He said scientists were looking forward to being able to perform gene transplants in 10 years time, so that newly fertilised eggs would have a gene pool with resistance to diseases.

Dr Jim Gibb, an assistant professor of beef production and management at the University of Illinois in the United States, said embyro transplants had increased significantly in North America in the last few years. They still represent less than one per cent of total cattle registrations in

1983, however, and the effect the method was having on the Hereford population in North America compared with artificial insemination was negligible.

“The cost would need to be greatly reduced to justify its widespread application for the sole purpose of genetic gain,” he said.

Artificial insemination offered a much more profitable means of increase than did embryo transfer, he said.

Mrs Rosa Peacock, a New Zealander who now farms Herefords with her husband in England, said embryo transplanting enabled them to make better use of their herd of 50 cows and bulls.

“In the last three years, our top calves have been embyro transfer,” she said. All cows were flushed non-surgically and embryos were implanted surgically into their fallopian tubes, which gave better results than non-surgically implanting, she siad. ’’The cow should be in the prime of life — 100 per cent healthy, aged three to 10 years, with no past history

of calving problems,” she siad. “We have twice had a 100 per cent take, and we average 65 per cent with fresh embyros.” She said that although veterinarians preferred using the method on heifers as they had less risk of previous infections, she preferred using “large, roomy cows.” Mr Don Anderson, treasurer of the Australian Poll Hereford Society, said it was an “exciting prospect” to be able to produce a cow’s lifetime production in one year using embryo transfer. However it was the most expensive method of multiplying progeny. “It is far better to use the cheapest method available he said.

He said some people were concerned about the dangers of introducing genetic abnormalities with artificial insemination and embyro transfer, yet these abnormalities were in fact more quickly exposed by using these methods.

Dramatic progress could be made if superior stock were used that could multiply quickly, he said.