URBANA, IL. — Lysine is an essential amino acid for lactating cows and, when added to the diet at adequate levels, helps increase milk production. But could lysine benefit cows in other ways? A new study from the University of Illinois suggests that rumen-protected lysine may improve fetal health if fed during the transition period.
“Immediately after birth, many changes occur in childhood. The cow had 100kg of calf, placenta and fluid, but 30-40 days after calving, the uterus should shrink again and prepare for the next pregnancy. There are a lot of cells that are being renewed, and the cow is then potentially vulnerable to infection and inflammation,” said Phil Cardoso, associate professor and faculty extension specialist in the U of I department of animal sciences.
Cardoso and his team added a rumen-protected lysine product at a rate of 0.54% to the total mixed ration (TMR) for 28 days prior to calving. After birth, lysine supplementation was added at 0.4% for 28 days. Cows received lysine supplementation before or after calving, or both, while a control group did not consume any supplemental lysine at any time period.
“We found that genes involved in the production of inflammatory proteins in the uterus were reduced by rumen-protected lysine, particularly in cows receiving the amino acid before and after calving. And genes involved in keeping the uterus clean were more active. Overall, our results show that these cows have less inflammation, which means they can use less energy to defend against infection,” said Cardoso. “It’s simply more efficient.”
In addition to characterizing gene expression in the uterus, the team looked for evidence of metritis, a uterine infection that affects 30% of US dairy cows after calving. Although the general inflammatory state of the uterus improved with lysine supplementation, the researchers found no statistical difference in metritis between cows consuming and not consuming lysine.
“Metritis is a clinical manifestation of inflammation of the uterus. It takes a bigger challenge than the environment to show this. Perhaps our economy does not create real tension in this regard. We found a difference in the subclinical form, also called subclinical endometritis. When we counted the number of inflammatory cells (PMN) in the uterus, cows receiving rumen-protected lysine had fewer cells, indicating less inflammation,” said Cardoso.
The team also tracked the first postpartum follicular growth cycle in the ovaries. Lysine did not affect the time to first ovulation and follicle diameter at ovulation, which averaged 18 days in milk for all groups.
Cardoso was neither surprised nor disappointed that lysine did not affect ovulation. Uterine health right after birth is more important than manufacturers think, she says.
“When farmers are asked how they evaluate reproductive development and productivity, the answer is always pregnancy. Usually, farmers breed cows about 60-70 days after calving, but if this fails, it is often due to events such as pre-breeding metritis or subclinical endometritis early in the cycle. This study shows that rumen protected lysine can help your cow succeed immediately after calving so she can achieve a favorable pregnancy later on.
The effects of lysine overlap with previous work by Cardoso looking at the rumen-protecting methionine, another limiting amino acid, in lactating cows. It showed genes affected by methionine related to inflammation and estrogen production and increased embryo survival.
“Our recommendation is to use both rumen-protected methionine and lysine,” says Cardoso. “We know that both amino acids are limited in lactating cows, but it is not clear whether the standard food sources, corn or blood meal, pass through the rumen to provide the cows with the amounts they need.”
Although rumen-protected lysine and methionine products are not widely integrated into commercial feed, Cardoso says nutritionists are beginning to recognize their importance in the industry.
“Those who reveal what it takes to get results are nutritionists and knowledgeable about rumen-protected amino acid products. But we also want to educate farmers, so they can start a conversation with nutritionists: “Hey, could this help me?”