It’s difficult for cattle to get enough metabolizable, or bypass, methionine in their diets. The traditional dairy cow diet with alfalfa, corn silage and soy-based feedstuffs is typically short by up to eight or nine grams of bypass methionine. It is also recognized that growing beef cattle can benefit from five to 10 grams per day of additional methionine under a variety of feeding and management conditions, including high forage range diets.

Methionine has been identified as the first limiting amino acid and is necessary for a cow to synthesize protein. If there is not enough soluble protein in the rumen, then microbial protein production is minimized and growth and development potential is limited. Methionine also is part of a chain reaction in the animal’s body that helps protect proteins and cells from oxidation. It is a precursor to cysteine, which is one of the sulfur-containing amino acids that activate major antioxidant enzymes to help detoxify extra free radicals so they can’t cause damage.

Since methionine plays several roles in a cow’s metabolism and the cow cannot produce enough of this essential amino acid on its own, it is important to supplement the diet.

“Supplementing rations with a methionine hydroxy analogue is an economical way to have a positive impact on the health and performance of the animal,” says Dennis Nuzback, DVM, PhD, Novus International, Inc. “When feeding 25 grams, it can provide an average of 8 grams of bypass methionine at its published bypass rate of 40%, leading to an increase in microbial protein and efficiency, ADF and NDF digestibility, and contributing to protein and enzyme synthesis, immune system response and overall maintenance of health.”

According to Nuzback, adding a high quality methionine supplement has been shown to improve performance in beef cows, including increased average daily gain, improved reproductive tract scores and reproductive efficiency. It also can increase milk, fat and protein yields in dairy cows, and helps support oxidative balance.

“Many veterinarians are educating themselves on nutrition and how to balance rations, to provide another service to clients,” Nuzback says. “By becoming more efficient with ration formulation software such as NRC 2001, CNCPS and others, they can evaluate diets, identify nutrient requirements and learn how to balance for metabolizable methionine. It’s important to balance for the right amount of a methionine hydroxy analogue supplement – not enough doesn’t maximize its potential, and too much wastes product and money.”