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Precision management

by Wyoming Livestock Roundup

UW Extension educator discusses importance of ewe nutrition from breeding through lambing

The short days of December and January mark an important milestone in the production cycle of a sheep flock – breeding season. And with lambs hitting the ground in just a short five months, proper ewe nutrition throughout pregnancy is critical.

In an effort to ensure producers have success when they start lambing come spring, University of Wyoming Extension Sheep Specialist Dr. Whit Stewart gave a presentation on the importance of sheep nutrition from breeding through lambing during the 2023 West Central States Wool Growers Convention, held at the Riverside Hotel in Boise, Idaho Nov. 2-4.

To begin, Stewart noted for most sheep producers, feed represents one of the highest costs on an operation in any given year. But, with the help of precision nutritional management, producers can alleviate some of these expenses. 

“We know sheep require certain nutrients throughout the calendar year but we also know because feed inputs are so expensive, we have to tailor flock nutrition appropriately to keep these costs in line,” he stated. 

Caloric requirement


Stewart noted environmental and operation-specific challenges can make it hard to create a precision nutritional management plan, especially for range flocks. However, in an effort to understand caloric requirements of ewes across different flocks, he encouraged producers to think about their own dietary requirements and exercise regimes. 

“We can compare a ‘housed’ flock to someone who works an office job and a range flock to those of you who don’t pay a herder on your operation,” he remarked. “The difference in the caloric expenditure of a housed animal versus an animal out on winter range is the grazing animal has to travel and expend energy to eat.” 

“The muscular work required for the animal to travel over the country comes at a cost,” he continued. “I know many of us are aware of this, but sometimes we fail to think about how different nutritional requirements are in different environments.” 

Another consideration for caloric requirements is type and size of sheep. 

According to Stewart, body size significantly contributes to daily intake. 

He also pointed out time of year and stage of production is critical for determining caloric requirements and daily intake. 

“I want to draw everyone’s attention to a ewe’s maintenance requirement, which is about 13 weeks a year, give or take three or four weeks on either side,” he said. “This is when dry matter intake is the lowest it will ever be, and consequently, total digestible nutrients and crude protein (CP) are much cheaper.” 

“During maintenance and other periods where ewes don’t have such high requirements, there are monetary savings that need to be realized,” he added.

Flushing and pre-breeding

Although many producers are familiar with flushing, Stewart noted the biological response from ewes has become better understood in the past decade. 

In fact, Stewart shared the effective increase of energy, glucose and other hormones in response to flushing is much quicker than previously believed. 

“It is really pretty quick – two to six days,” he stated. “Most of us are flushing our ewes for 17 to 30 days.”

He continued, “I am not going to be prescriptive in the exact amount of time, but what I will say is it doesn’t take long to see an ovulatory response depending on where the ewe is in her estrous cycle.”

With this, Stewart also pointed out it is still critical to flush ewes within the first 45 days of gestation and not to be too hasty when pulling feed. 

“Make sure to maintain a decent level of nutrition after flushing,” he said. “This is really important because if producers pull feed too quickly, they can go backwards in terms of early recognition of pregnancy and fetal development.” 

Post-breeding deliberations

As ewes move into early gestation following conception, producers will need to keep the animal’s changing requirements in mind. 

“I know many producers are aware of the increase in a ewe’s CP requirements throughout her different stages of production, and we all do our best to try to meet those needs. But, I want to talk about the management implications of not having enough energy,” Stewart stated.

“A higher level of fetal weight constricts space in the rumen, which creates some challenges as we move into late gestation,” he further explained. “As rumen volume constricts, the ability of the ewe to consume enough feed – especially if it is low-quality feed – is limited.” 

Stewart noted this can result in pregnancy toxemia and hypoglycemia. Therefore, to keep the amount of ewes who experience these health issues to a minimum, producers should be attentive to predisposing factors, which include overconditioning and tooth and mouth issues. 

Another dietary consideration for ewes in late gestation, according to Stewart, is mineral intake. 

“Minerals are so important because as we move into late gestation, the more minerals we feed, the more minerals are shuttled to the fetus – both across the placenta and accumulated in colostrum,” Steward concluded. “Minerals are involved in a lot of biological processes that we might not traditionally acknowledge as important, and making sure we feed enough of them is critical.” 

Hannah Bugas is the managing editor of the Wyoming Livestock Roundup. Send comments on this article to

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