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Winningers introduce in vitro fertilization to Wyoming

by Wyoming Livestock Roundup

Cody – Cow Country Genetics, a well-known embryo transfer company in northwest Wyoming, recently introduced in vitro fertilization (IVF) to their lineup of services, diversifying the company further and offering more options for cattle producers in the state and region 

“We are working with In Vitro Brasil – the largest IVF company in the world,” says Dave Winninger, owner of Cow Country Genetics. “They began in Brazil and now have 23 labs worldwide.”

When In Vitro Brasil founded a partnership with ORIgen in the fall of 2013, they simultaneously opened their first U.S. lab near Billings, Mont.

“They set up a lab in ORIgen’s conference room,” Winninger explains. “We produced the first pregnancies out of their lab in early December.”

“They incubated the embryos, and I put them in recipient cows the next week,” he continues. “We got six pregnant out of 10. We are right on the cusp of this technology.”

Benefits of IVF

Winninger notes that there are several advantages to using IVF.

“We can either super-ovulate the cow or not,” he says. “She makes waves of follicles all throughout her cycle naturally. We can either harvest what she naturally produces or super-ovulate the cow to make them grow larger.”

While most American companies super-ovulate cows, In Vitro Brasil chooses to harvest the oocytes produced naturally by the cow.

“If we don’t super-ovulate the cows, like the Brazilian method, we can aspirate the same cows every other week,” Winninger explains. “Cows start a new follicular wave, and we can aspirate it.”

While some breeds may produce more oocytes by super-ovulating cows, others do not. Because he works with In Vitro Brasil, Winninger does not super-ovulate cows to collect oocytes.

At the same time, Winninger notes that oocytes can be harvested from pregnant cows, as long as her ovaries can be reached. 

“We can harvest oocytes from a pregnant cow until she is about 100 days pregnant,” he says. “We can also harvest oocytes sooner after the cow calves.”

Harvesting oocytes from pregnant cows allows producers to produce a calf each year and also produce pregnancies in recipient cows. Cow do not have to be left open for a year as in embryo transfer.

Age and injury

Winninger also notes that IVF also allows older or injured cows to be aspirated, keeping their genetics in the herd.

“I had two customers who sent me cows. One had some really old North Devon cows that didn’t work for embryo transfer anymore,” he says. “We produced 27 pregnancies out of four cows that would have been canners.”

Winninger explains, “He wanted the genetics, but the cows weren’t working reproductively anymore. They didn’t react to the hormones because they had been super-ovulated so many times.”

“We can recover genetics from cows that weren’t reproducing any more because of age,” he continues. “If we super-ovulate repeatedly, many times the cows won’t fertilize anymore. We can bypass the fertilization in the cow by doing IVF.”

Injured cows that can’t be bred traditionally can also produce oocytes by IVF. 

Stretching supply

An additional benefit of IVF can be found in its ability to make rare or old semen stretch across more cows. 

“I have another client who has some semen that is pretty rare and expensive,” Winninger says. “We aspirated three cows and fertilized the oocytes using only one straw of semen.”

IVF allows fertilization of multiple eggs from only one straw of semen.

Harvesting oocytes

Winninger works with Powell veterinarian Tori Lewis in harvesting oocytes. 

“It takes more people to harvest the oocytes,” Winninger says. “Tori supervises and works in the lab. My daughter Lacy works in the lab, and Tori’s vet tech prepares my equipment.”

Additionally, one person helps in handling cattle.

They have to work quickly to ensure the oocytes remain viable. 

“If the incubating media is exposed to air for 20 minutes, it kills the oocytes,” he says. “We have to keep it in a carbon dioxide environment. It is a little more tricky than embryo transfer.”

Inseminating cattle

After harvest and fertilization in a petri dish, Winninger notes that the embryos are grown for seven days before being transferred to a recipient cow or being frozen. 

“In Brazil, they vitrify their IVF embryos, which means they make them into glass, instead of freezing them. It is a more difficult process, and they have to be thawed differently,” Winninger explains. “To work in America, we have to freeze the embryos in ethylene glycol so technicians are familiar with how to thaw them.”

IVF embryos can also be put in either fresh or after they are frozen.


Despite the new nature of the technology for Cow County Genetics, Winninger says he has seen success in both harvesting and producing pregnancies. 

“We received fresh IVF embryos at a ranch in South Dakota and produced 74 percent pregnant cows,” he says. “The next year, we put in 330 frozen IVF embryos and got 52 percent pregnant.”

“These are great numbers,” Winninger notes. “If we can get 65 percent pregnant with fresh embryos and 50 percent with the frozen IVF embryos, that is probably economically viable.”

“As with any new technology, we have to learn how to be efficient and profitable,” Winninger comments. “We feel like IVF is at the place where it is profitable and working well. I think IVF will be complimentary to the regular embryo transfer that we do.”

Saige Albert is managing editor of the Wyoming Livestock Roundup and can be reached at

Explaining IVF

IVF is similar to embryo transfer, but the two processes differ in several key ways, offering benefits for producers. 

“In normal embryo transfer, the cow is stimulated to make extra eggs,” Dave Winninger of Cow Country Genetics explains. “She comes into heat and ovulates those eggs, and we inseminate the cow. The eggs are fertilized in her oviduct.”

After seven days, the embryos in the cow’s uterus are flushed using a saline solution. 

“Embryo transfer is in vivo, which means ‘in life.’ The fertilization happens in the cows,” he continues. “In vitro means that these things are happening in the petri dish.”

Rather than harvesting the fertilized embryo from a donor cow, IVF harvests the oocyte – or the unfertilized egg – from the follicle of the cow’s ovary. 

“The cow never ovulates with IVF,” Winninger says. 

Because the process is quite different, WInninger also notes that different equipment is required.

“We use an ultrasound with a needle. After visualizing the cow’s ovary, I poke the needle into the follicle, and a vacuum sucks out the contents of the follicle to get the egg,” he says. “These are not fertilized. It is just the egg with a cloud of cells around it.”

The cells surrounding the unfertilized egg are very important, Winninger comments, noting that the cells produce hormones stimulating fertilization by sperm cells. 

“We have to have the right equipment, so we can get the eggs out of the cow with the cells around them intact,” he says. “That is tricky.”


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