ISU animal research evaluates ultrasound use, feeding liquid brewers yeast

URBANA, Ill. — Parturition management is one of the most popular classes in the Department of Agriculture at Illinois State University.

“For this class, the students are responsible for the birthing of animals at our research farm by Lexington,” said Jennifer Earing, assistant professor in the Department of Agriculture at ISU.

Three to four students sign up for six-hour shifts.

“This gives them a realistic perspective, and if they’re not comfortable with a situation, they can call the teaching assistant or the farm manager,” said Earing during a presentation at the Illinois Lamb and Wool Producers Sheep Day.

About 400 students are enrolled in the ISU Department of Agriculture.

“We’re getting a lot of students that want to go to vet school, but have minimal animal experience,” Earing said. “Most of our classes have a lab associated to it and the sheep are the favorite species because they’re not as intimating as the cattle.”

The ISU farm includes about 100 head of Simmental/Angus cattle, 60 Dorset/Suffolk ewes and 100 sows.

Earing talked about a research project at the farm that evaluated the ability to estimate fetal age using ultrasound in early gestation of ewes.

“The study in 2016 showed 90% accuracy by day 31 and 100% accuracy at day 45,” she said.

The ISU researchers conducted a second study with 15 Dorset ewes that were synchronized and exposed to a ram for a 24-hour period. The ewes were scanned by ultrasound starting at day 21 and then every couple of days until day 59.

“We recorded information about the fetal count and we took video clips and made measurements from those clips that included actual lambing date and lamb body weight,” Earing said.

Eleven out of the 15 ewes in the study were pregnant.

“For fetal counting, at day 21, the accuracy was 10% and there was a big jump from day 21 to 26 to 60% accuracy,” Earing said. “The accuracy generally increased until the highest at day 49 at 90% accuracy.”

Lamb Survivability

Julissa Navarrete, a graduate student at ISU, talked about her research project that involved feeding ewes liquid brewers yeast, a byproduct of the brewing industry.

“Not a lot of research has been done on lamb mortality,” Navarrete said.

“Research reports providing good nutrition to ewes is important to get more vigorous lambs and another aspect of providing good nutrition is improving the quality or quantity of colostrum,” she said.

In addition, natural immunoglobulins are a factor that affects lamb survivability.

“Ewes have a placental barrier which prevents passage of immunity so lambs are born with no immunity,” Navarrete said. “Ewes provide passive immunity through colostrums so the first 48 hours is the most critical time for lambs to provide adequate colostrum intake.”

Therefore, Navarrete said, if colostrum is improved, that can increase the lamb survivability rate.

“The objective of the study was to evaluate the byproduct we got from a local distillery by feeding it to the ewes to see of there was improvement in colostrum quality or immunity for the ewes’ offspring,” she said.

The study included 14 ewes — seven in the control group that were fed a traditional late gestation diet and seven that were fed 60 grams of dry matter per head per day of liquid brewers yeast mixed in with grain.

“To measure the passive immune transfer, we gave a parainfluenza vaccine to the ewes prior to starting the trial,” Navarrete said. “It is not a very common vaccine for our sheep so no antibodies would be present in the ewes for this vaccine.”

Blood samples were taken to monitor immunity through gestation and after lambing.

“Prior and post lambing all ewes were positive for the vaccine so their immune system was working,” Navarrete said. “And all the lambs were positive for the vaccine.”

Colostrum samples were collected from the ewes four hours postpartum and sent to a lab for analysis to determine butterfat and protein concentrations.

“We also ran the samples through a Brix refractometer,” Navarrete said. “Above 22% Brix is considered high quality colostrum, but we didn’t see any significant difference in measuring the antibodies in the colostrum from the two groups of ewes.”

The conclusion of the study, Navarrete said, was the liquid brewers yeast didn’t improve or negatively affect immunity or colostrum quality.

“More research needs to be done to determine what quantity of liquid brewers yeast needs to be offered to see improvements,” she said.