Lambing Webinar: UW Extension discusses lamb survival and ewe performance ahead of lambing season

On March 17, the University of Wyoming (UW) Extension Sheep Task Force held the first of two webinars in the task force’s gestational and lambing miniseries, focused on lamb survival and ewe performance.

The webinar featured a presentation on the importance of colostrum and considerations for passive transfer by UW Extension Sheep Specialist Dr. Whit Stewart, as well as comments from Isaac Brunkow and Steve Kier, staff members at the U.S. Department of Agriculture (USDA) Animal Research Service’s U.S. Meat Animal Research Center (MARC) located in Clay Center, Neb.

Importance of colostrum

To underscore the importance of colostrum, Stewart emphasizes lambs are born without circulating antibodies. 

Since lambs do not receive antibodies across the placenta, they are dependent upon receiving maternal antibodies from the ewe’s colostrum – a process called passive transfer.

“One hundred percent of a lamb’s immune function comes from colostrum consumed within the first 24 hours,” Stewart states, noting colostrum intake impacts everything from protection in the first stages of life to critical nutrients and signals affecting digestion and growth.

“Without colostrum, the lamb’s immune system fails entirely,” he adds.

Passive transfer

Stewart also provides some context on what makes for good colostrum and successful passive transfer from both an immunological and a nutritional perspective, noting concentration of colostrum and adequate consumption are both critically important.

Stewart also highlights the importance of timing for successful passive transfer, noting concentrations of colostral antibodies and fat-soluble vitamins decrease soon after lactation begins as colostrum supply is replaced with milk.

Additionally, he emphasizes a lamb’s ability to absorb colostral antibodies is time sensitive, as changing pH levels in the gut and the changing structure of the small intestine leads to a decreased ability to absorb antibodies as time progresses. 

In addition to proper timing, it is also critical to ensure lambs get enough colostrum to get off to a good start immunologically. 

“A lot of our challenges with failed passive transfer are a result of inadequate consumption,” Stewart says, noting in cases where lambs struggle to suckle, intervention with an esophageal feeder may be required.

Ewe considerations

Since antibodies are passed from ewes to lambs, Stewart lists some factors to take into consideration in order to prepare ewes for successful passive transfer ahead of lambing. 

He also notes studies have shown good energy supplements can have positive outcomes on colostrum production.

“Undernutrition will reduce the amount of colostral antibodies present and the quantity of colostrum produced,” Stewart says. “A readily available soluble energy source, whether from a digestible byproduct or a more concentrated energy source like corn or grain, can help improve the quality and quantity of colostrum produced.” 

Additionally, Stewart notes vaccinations ahead of lambing can help ensure colostral protection is achieved.

He highlights the importance of clostridial vaccinations in late pregnancy – administered  around four weeks before lambing – to increase antibodies in the bloodstream and protect against diseases like enterotoxemia and tetanus.

Stewart also cautions against vaccinating lambs within the first 24 to 48 hours of life, noting these early vaccinations can actually antagonize the passive transfer process.  

Finally, Stewart highlights some benefits of incorporating tools like refractometers and other resources into lambing operations in order to assess colostrum quality and be better prepared to give young lambs a leg up. 

Orphan lamb management

Following Stewart’s presentation, Brunkow and Kier share comments on their work at U.S. MARC to reiterate the importance of colostrum in early stages of life and offer some insight on orphan lamb management.

According to Brunkow, roughly 2,000 head of breeding ewes are housed at U.S. MARC, with a flock composed of five breeds – Suffolks, Polypays, Katahdins, Composite IV or “Easy Care” and Romanovs. 

At the facility, Kier explains ewes are rarely left to raise more than two lambs, so in cases of triplets or higher, the smallest lambs are removed and raised in a nursery.

Additionally, lambs from ewes with lower milk production rates, orphaned or separated lambs, lambs with trouble suckling and hypothermic lambs are also given extra attention in the nursery.

Newborn nursery lambs are given a powdered colostrum solution, with Kier emphasizing he aims for 10 percent of the lamb’s bodyweight in fluid ounces of colostrum to be administered within the first two feedings.

After an orphan lamb establishes a strong ability to nurse and remain healthy, Kier says they are usually marketed as bottle lambs around three weeks of age. 

The second installation of the UW Extension Sheep Task Force Gestational and Lambing webinar miniseries was held on March 26 and featured comments on nutritional strategies and research-based approaches to reduce metabolic stress around lambing from Stewart and Dylan Laverell. 

Grace Skavdahl is the editor of the Wyoming Livestock Roundup. Send comments on this article to roundup@wylr.net.