Semen bank ensures future of livestock species

Agriculture Canada’s Canadian Animal Genetic Resources in Saskatoon holds a large collection of frozen semen and some embryos from cattle, pigs, sheep, goats, horses, poultry, deer and elk. Everything is stored in liquid nitrogen, colour coded and entered into a database.  |  Barbara Duckworth photo

Agriculture Canada maintains more than 300,000 doses of frozen semen and embryos from a variety of livestock species

SASKATOON — If a disaster should ever harm any part of Canada’s livestock sector, there is hope for recovery.

Agriculture Canada’s Canadian Animal Genetic Resources (CAGR) housed in Saskatoon holds a large collection of frozen semen and some embryos from cattle, pigs, sheep, goats, horses, poultry, deer and elk.

Many livestock breeds are recognized in Canada, but within 10 years there will be fewer breeds within some species, says curator Carl Lessard.

“They are disappearing faster and faster and that is why we are making an effort to keep them,” he said.

Lessard collects samples from Canadian farms, while others are donated by producers.

Working with team members Pamela Walker and Crissandra Auckland, as well as a few graduate students, Lessard catalogues every straw of semen and enters it into a database for conservation and research.

“We work with industries to ensure that in the future if they need to have access to the semen (it is here),” he said.

The researchers have more than 300,000 doses of mainly bovine collections, but they want more of everything from sheep to chickens. Besides the mainstream breeds, the centre also works with organizations such as Heritage Livestock Canada to find animals and preserve rare genetics.

“Many farms have difficulties finding replacements and this is where they can come,” he said.

Among the cattle samples, Angus and Holstein semen is the most plentiful, but if something happened they could rebuild the breeds.

“We ask the association what they want to preserve,” Lessard said.

Later this year the centre is launching a website with its database so the public can see what is stored. The United Nations’ Food and Agriculture Organization has a similar international database, and Lessard contributes Canadian information to those records.

Besides preserving rare species, the centre wants to collect more swine and poultry samples because the breeding programs have evolved into genetic lines rather than distinct breeds.

A technique was developed in recent years to collect semen from dead animals. Scrotums can be carefully packed and delivered to the laboratory to extract semen while it is still alive.

“We start to lose motility right away, but we have a good proportion of sperm cells that are in the reservoir,” he said.

“It is one way to save some genetics. We receive five and 10 scrotums per year and we are ready to take more.”

A greater quantity of semen is needed for use in artificial insemination because some properties are lost if the semen is not from direct ejaculate.

The greatest genetic loss appears to be in chickens.

Within two years Lessard hopes to have perfected protocol to transfer ovaries from rare breeds to conventional chicks to rebuild a population.

“We hope to save heritage breeds by freezing the gonads and putting them in a recipient and generate some eggs,” he said.

Using tweezers and Q-Tips, ovaries can be surgically removed from anesthetized chicks one to three days old. The chicks are allowed to reach maturity and hopefully produce viable eggs from the new ovary. The greatest challenge right now is rejection of the implanted ovary, said Lessard.

On the research side, Walker analyzes samples for genetic diversity using specific genotype panels for each species.

She looks for inbreeding co-efficients to see how genetic material clusters together to determine if the animals are closely related or diverse. She can determine hybrid vigour and assess the genetic health of the Canadian livestock population.

The analysis provides a unique fingerprint of the animal so it can be compared to others within and outside of other breeds.

“We can tell how diverse a population is, or how inbred or how heterogenous or homogenous a population is, and whether or not we need to warrant more conservation initiatives because the inbreeding co-efficients get high,” she said.

In addition, the work can look at unique characteristics within a breed.

“I also characterize samples for individuals that are looking to have a breed recognized,” Walker said.

One of her projects looked at a rare cattle breed from Eastern Canada called the Lynch Lineback.

“It is its own breed at this time because it clusters completely different,” she said.

Research also evaluates sperm health and whether it is moving properly.

A semen straw is warmed to 37 C and they may lose up to half the sperm when it is thawed out. Some individual animal’s sperm does not freeze well after collection.

In the field the semen can be collected, prepared and frozen, but results are often better if it is done at the laboratory.

“If I go into the field for beef or rare breeds, we could have a bad freezer and end up with no motility at all,” Lessard said.

However, dead sperm is retained because it could be useful in the future.

Lessard’s team sees this as important work and much of what they do is promoted through word of mouth among producers and breed associations. They want more people involved in preserving common, rare and distinct genetics.

“A lot of the rare breeds are preserved because of passionate producers,” he said.

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