Lysine linked to reproductive health in dairy cows

Photo: University of Illinois

Dairy cattle are especially prone to reproductive health issues around calving, which affects fertility and conception rates in the next cycle, and a new University of Illinois study is showing that rumen-protected lysine may improve uterine health if fed during the transition period.

“Right after calving, the uterus is undergoing a lot of changes. The cow had 100 lb. of calf, placenta, and fluids in there, but by 30-40 days after calving, the uterus has to shrink back down and get ready for the next pregnancy. There are a lot of cells regenerating, and the cow is potentially vulnerable to infection and inflammation at that time,” according to Phil Cardoso, associate professor and faculty Extension specialist in the University of Illinois Department of Animal Sciences.

In the study, Cardoso and his team added a rumen-protected lysine product to total mixed ration at 0.54% for 28 days pre-calving. After calving, the lysine was added at 0.4% for an additional 28 days. Cows got the lysine additive before or after calving, or both, with an additional control group consuming no supplemental lysine in either time period.

“We found genes involved with producing inflammatory proteins in the uterus were reduced with rumen-protected lysine, especially in cows that consumed the amino acid before and after calving. And genes involved in keeping the uterus clean were more active. Altogether, our results indicate less inflammation in these cows, meaning they can spend less energy defending against infection,” Cardoso said. “It’s just more efficient.”

Along with characterizing gene expression in the uterus, the team looked for evidence of metritis, a uterine infection affecting 30% of U.S. dairy cows after calving. While the overall inflammation status of the uterus improved with lysine supplementation, the researchers didn’t detect a statistical difference in metritis in cows that consumed lysine and those that didn’t.

“Metritis is the clinical presentation of uterine inflammation. It requires a larger degree of challenge from the environment to show up. Perhaps our farm does not present real stress in that regard. We did find a difference in the sub-clinical form, also called subclinical endometritis. When we counted the number of inflammatory cells (PMN) in the uterus, cows receiving rumen-protected lysine had a lower number of cells, indicating less inflammation,” Cardoso said.

The team also tracked the first postpartum follicular growth cycle in the ovaries. Lysine didn’t affect time to first ovulation – that averaged 18 days in milk for all groups – nor the follicular diameter at ovulation.

Cardoso is neither surprised nor disappointed that lysine didn’t affect ovulation. He said the health of the uterus right after calving is more important than producers think.

“When you ask farmers how they assess reproductive progress and fertility, the answer is always pregnancy. Usually, farmers are breeding cows around 60 to 70 days after calving, but if it is unsuccessful, it’s often because of events like metritis or subclinical endometritis that happen prior to breeding, earlier in the cycle. This research shows rumen-protected lysine can set your cow up for success right after calving so she can achieve a favorable pregnancy later.”

The effects of lysine line up with Cardoso’s earlier work looking at rumen-protected methionine, another limiting amino acid in dairy cows. He showed methionine affected genes related to inflammation and estrogen production, and increased embryo survival.

“Our recommendation is to use both rumen-protected methionine and lysine,” Cardoso said. “We know both amino acids are limiting in dairy cows, but it’s not clear that standard dietary sources – corn or bloodmeal – make it through the rumen to supply cows with the amount they need.” 

Tim’s Take

Reproductive health is a sore point in many dairy operations, but having a successful reproduction program is more than synchronizing breeding cycles and detecting estrus on time. At calving, the cow’s reproductive tract must recover while she devotes a massive amount of bodily resources to milk production. It seems from this research that supplemental protected lysine can help create a beneficial uterine environment, getting the cow ready for her next gestation.