Polypay Takes on Parasite Study

Polypay Takes on Parasite Study

TERRI QUECK-MATZIE
Special to the Sheep Industry News

Internal parasites are one of the greatest threats to sheep in the United States, a fact that many producers know all too well.

“There’s nothing more discouraging than finding two or three dead sheep every morning,” says Brett Pharo, of Back Acre Farm in Rapid City, Mich., and president of the American Polypay Sheep Association. “It just makes you want to quit.”

Those interested in producing sheep only for meat have found some success in turning to hair sheep breeds such as St. Croix, Barbados Blackbelly and Katahdin that are known for parasite resistance. But for the wool producer, options are limited to a sometimes expensive, and increasingly ineffective, array of deworming products.

“Like any organism, the worms eventually develop a resistance to the products,” says Pharo. “There are fewer and fewer on the market that treat the problem successfully.”

With the help of an ASI Let’s Grow grant, the APSA is exploring a third option. During the next three years, the group will study the impact of quantitative genetics on parasite resistance.

Using the National Sheep Improvement Program’s system of Estimated Breeding Values, the study sets three main goals: increase the number of Polypay sheep with FEC (fecal egg count) EBVs, increase the DNA database on Polypay sires with FEC EBVs, and increase the number of commercial rams with FEC EBVs available to commercial operations across the country.

“In other words, we want to give them a large pool to buy from,” says Jerry Sorensen, one of the study instigators.

“Small producer groups have experimented with this approach,” says Christopher Schauer, director of the North Dakota State University Hettinger Research Extension Center and a Polypay breeder. “Now we want to take that small group success and make it a national effort. It’s especially important to producers in the eastern and southern states, but we’re all in this together. Just because I don’t have a parasite problem because I’m in North Dakota doesn’t mean I don’t have sheep with resistance that could benefit those who do.”

John Anderson, of Lambshire Polypays in Shreve, Ohio, is one of those producers who has experimented with genetic selection for parasite resistance. He has customers wanting to improve parasite resistance within their flocks, particularly those to the south and east.

“I’ve been doing it since 2009, before NSIP, and I’ve been able to make some progress,” says Anderson. “It helps to now have an EBV, and will help even more to have a national effort.”

Like Anderson, Pharo says he stopped treating lambs 10 years ago and relies on genetic selection to control parasites.

“I’ve been able to make headway toward genetic parasite resistance, but being able to select for fecal egg count EBVs will speed up and quantify the process.”

“We can get there with wool sheep,” continues Anderson. “If they can do it in Australia and New Zealand, we can do it here.”

In New Zealand, it is possible to select rams that shed 60 to 70 percent fewer parasite eggs than historical averages.

Being part of the solution

The APSA hopes to increase the number of FEC data submissions from fewer than 200 from two or three producers to 3,000 from more than 10 producers in the course of the three-year study. The increase in numbers will improve the accuracy of the database, as well as the breeding stock selection pool. To entice producer participation, the APSA will instruct producers on proper collection and shipping methods, as well as defraying the cost of sample submission, by covering the cost of up to 100 samples per producer.

Participating producers must have at least one contemporary group that meets the study criteria. Contemporary groups need to consist of at least 10 lambs from each of at least two sires that have grazed together for at least 45 days.

“We hope to be able to identify the resistant genetic lines with this study,” says Schauer. “We also hope to eventually identify the genetic marker for what we know is a heritable trait.”

Along with fecal egg samples, participating producers must agree to submit a DNA blood card on every lamb’s sire. The NDSU Hettinger Research Extension Center has agreed to store the cards for further research.

“We don’t have the funds in this part of the project for that research,” explains Schauer. “But we hope to get there some day.” Others in the industry have expressed interest in using the samples for genetic research on other heritable traits, as well. “It will provide us with an incredible information source down the road.”

Pharo sees the breed association as an important figure in improving the economics of an industry that takes advantage of grazing as a feed source.

“This will give commercial producers an option to look at, and select by, reliable data. Despite deworming and pasture control efforts, producers experience a significant amount of death and gain loss. This could make a big difference in the future of our industry.”

Schauer agrees the APSA has a role to play.

“The breed associations were the first producer working groups, so it makes sense for them to take on this role,” says Schauer. “They can provide more service than just animal registration, they can make change happen within a breed. They work to make sheep fit the commercial sheep industry’s needs, while making the breeding stock more marketable for the breeder. This new program fits that mission.”
The study also fits broader industry-wide goals.

“We certainly want to thank ASI and the Let’s Grow Program for backing this effort,” says Schauer. “Their approach toward producer-driven, industry-oriented work is making a difference.”

Polypay producers interested in participating in the study should contact the APSA or Schauer for further information.

“The growth of this industry will depend on grazing non-tillable lands,” says Pharo, “and that means fighting parasites. We have a chance to help address that challenge, and find a sustainable solution to the problem.”