EDMONTON – Hog producers may soon be able to safely introduce new genetics into their herds through non-surgical embryo transfer technology.
Embryo transfer is the most biosecure way of introducing new genetics into herds, said Michael Dyck, assistant professor and researcher with the University of Alberta’s swine research and development program.
“Once you have the embryos you can pretty much walk into any barn and transfer the embryos,” he said.
Embryo transfer has been common in cattle for 20 years, but non-surgical embryo transfer has only been possible in hogs for the past four to five years because of new equipment.
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The breakthrough came with the development of equipment to get embryos through the swine cervix. In cattle, the cervix is shorter and the reproductive tract can be manipulated through the rectum.
“Our embryo manipulation techniques aren’t as developed in swine as cattle,” said Dyck, who uses a catheter developed at Wageningen University in the Netherlands.
Cattle sperm and embryos can be frozen for years, usually without harm, but hog sperm, eggs and embryos don’t freeze well, said Dyck, who wants to work with American researchers to combine non-surgical embryo transfer work with new freezing techniques.
While the work is still in its infancy, it will be an important part of transferring genetics in the future, said Eduardo Beltranena, a pork development specialist with Alberta Agriculture.
“It’s a new way of delivering genetics to the units,” said Beltranena, who expects embryo transfer to be used on breeding farms in two to five years.
“That’s the way we’re going to bring in the elite genetics.”
So far 48 piglets have been born at the university through embryo transfer. Of the 19 embryo transfers, 10 resulted in successful pregnancies.
When selecting donor hogs, Dyck looks for gilts or young sows with good genetics.
Genetics in the recipient hogs don’t matter, but the sow must be healthy and have had at least four or five litters. Older sows that have had several litters have a higher success rate than sows with fewer litters.
“We want healthy animals that can get through gestation,” Dyck said.
Once the animals are selected, the reproductive systems of both animals are shut down using a synthetic hormone that inhibits estrus. When the timing is right, Dyck eliminates the hormone from the feed and allows the reproductive systems to start again.
Another hormone is used on the donor sow to introduce follicular development and a second hormone induces ovulation. Then the sow is bred and the embryos collected.
At this stage, there is no easy way to collect the embryos. The donor sow is killed, the uterus removed and the embryos flushed from the donor’s uterus. There are 20 ovulations per donor, but only 14 are collected, or about a 70 percent recovery rate.
Dyck then looks at the embryos through a microscope to see which are at the correct stage of development. It takes embryos from about two and a half sows to get enough embryos at the right stage to transfer. The embryos are put through the catheter and inserted into the cervix.
At day 30 of the pregnancy an ultrasound is done to check for pregnancy. Dyck said sometimes the pig aborts after 30 days, but at least they know there was success at the beginning of the pregnancy.
