January 25, 2002

Out-of-Season Lambing Ready for Producers, NDSU Researchers Say

The spring-born lamb is one of the most enduring images of sheep production, but after 15 years of study, North Dakota State University researchers have developed a system that has a 90 percent success rate for breeding sheep to lamb in the fall instead.

The benefits will include a more stable supply of sheep for sheep processors and consumers and improved prices for sheep producers who can supply lambs during seasonal lulls in production. "And one of the objectives has been to develop a system that can be adopted by typical sheep producers," says Tim Faller, sheep researcher and director of the NDSU Hettinger Research Extension Center. "We feel we’ve accomplished that."

NDSU’s out-of-season lambing system is also a good fit with another recent development in the North Dakota sheep industry, the formation of the Dakota Lamb Growers Cooperative. That cooperative has more demand for high quality lamb products than it can supply and those demands are especially critical during seasonal lows in supply, Faller says.

Reproductive cycles in sheep are driven by changes in day length and genetics. As a result, ewes are traditionally bred in the fall and lamb in the spring. Researchers have had some success in changing that cycle by treating ewes with hormones or confining them in barns where lights are controlled to mimic seasonal changes in day length. "Although that work was successful, we knew that just wasn’t practical for most producers in our region," Faller says.

The NDSU system relies on something Faller calls the "ram effect." Rams and ewes are isolated from each other except during specified breeding times. "The excitement that’s created by the smell, sight and action of bringing them together prompts estrous in the sheep," Faller says. " That in turn prompts physiological changes in the ram that translate into more aggressive breeding behavior."

Other key elements include a higher-than-normal ram to ewe ratio of one ram to 20 ewes and a focus on ewe nutrition. Good body condition for ewes is essential and an increase of energy and protein in the diet about two weeks before breeding can increase ovulation rates.

Genetics also plays a role. All of the research was completed with western white-faced ewes and ram types. "Western white faced sheep are the largest sheep gene pool in the United States. That makes us optimistic that a number of producers may be able to adapt out-of-season lambing technology on their farms and ranches," Faller says. Additional research will show how well other breeds of sheep may perform in out-of-season lambing systems.

Initially, the researchers used the ram effect to achieve out-of-season lambing success in an NDSU sheep flock that had been developed for fall lambing for more than a decade. "We wanted to see if our success was the result of the genetics in that flock or from the ram effect itself," Faller said. So researchers brought in market sheep of similar breed types -- both rams and ewes. "They popped right into the system," he said. "Out-of-season breeding success was comparable between those sheep and the sheep NDSU had been using for its research. We knew then, that the system could be practical for sheep producers."

Faller and other researchers involved in the project will outline the system at the NDSU Hettinger Research Extension Center’s Annual Sheep Day on Wednesday, Feb. 13. The event opens at 9:30 a.m. at the Hettinger Armory and continues until about 4 p.m. The event is free, features a sponsored American lamb Dinner at noon and will include sessions on sheep research and issues from experts in North Dakota, South Dakota and Montana.

At the Sheep Day, NDSU staff will distribute a new pocket management calendar that outlines key dates for creating and managing a sheep flock that lambs out of season.

Initially, ewes should be bred in April to lamb in September. The 10 percent to 15 percent of ewes that do not conceive will be exposed to Rams again in August for lambing in January. Likewise, ewes born in September will be too young to breed in April, so they’ll be bred to lamb in January as well.

"The entire system is focused on two 31-day lambing periods in September and January to minimize labor and management," Faller says. "If you want to maintain that schedule, you have to follow the calendar pretty closely."

Faller says producers who might be most interested in the system are those who are serious enough about sheep production to receive a significant portion of their income from sheep. "This probably isn’t something that the hobby or part-time producer is going to want to attempt," he says. "For producers who don’t have enough labor available, it allows them to spread their lambing out over the year and spread their marketing."

For producers looking to graze ewes, perhaps in a system to control leafy spurge, out-of-season lambing puts ewes on pasture all summer long. "And leafy spurge can be a good component of the diet for pregnant ewes," he says.

Feed costs are likely to increase under the system because lambs are weaned at 60 days and moved directly into the feedlot. Because lambing is split between September and January, the need for facilities is minimized. "However, the facility you use for lambing in January needs to be a good one," Faller says.

For more information on the system, contact Tim Faller at (701) 567-4323 or tfaller@ndsuext.nodak.edu . Roger Haugen, NDSU Extension Service sheep specialist can also provide information on out-of-season lambing. Contact him at (701) 231-7645 or rohaugen@ndsuext.nodak.edu .

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Source: Tim Faller, (701) 567-4323, tfaller@ndsuext.nodak.edu
Editor: Tom Jirik, (701) 231-9629, tjirik@ndsuext.nodak.edu

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