Something to Ruminate On

Amino acid balancing benefits extend beyond milk protein


For producers in the Federal Milk Marketing Order 30 or surrounding markets, a vast majority of the milk check is dictated by volume and value of milk fat and protein. While the pay price for milk fat within the FMMO 30 for March was strong at $3.24 per pound, milk protein has been near record lows the past few months. Projections for April and May protein values are even lower and are expected to be less than $1 per pound.

The degree of economic return from amino acid balancing dairy rations fluctuates with the pay price on milk protein and, to a lesser extent, milk fat. Current low protein prices generate questions on the value of amino acid balancing. The following are benefits to consider.

Amino acids are the building blocks of proteins. Conceptually, we continue to place less emphasis on dietary crude protein and more emphasis on the available grams of specific amino acids. Ration modeling programs can predict amino acids contributed from both dietary sources and rumen microbes.

The primary goal of amino acid balancing is to improve protein efficiency. As a result, amino acid balancing often yields an improvement in milk protein output. While increased attention is being given to several of the 10 essential amino acids, lysine and methionine are often referred to as the two most-limiting amino acids for milk protein synthesis in a lactating dairy cow diet. Supplemental methionine research not only supports greater protein percentages but also an increase in milk yield and milk fat. This is an important consideration given the value of milk fat in the current FMMO 30 market.

The benefits of feeding rumen-protected methionine go well beyond milk component responses.

Reproduction: Supplemental rumen-protected methionine fed to dairy cows has been shown to affect various aspects of reproduction, including follicle quality, the uterine environment, embryo composition and pregnancy recognition. As a result, methionine has been shown to decrease the risk of embryonic loss in dairy cows.

Transition cows: Supplementing rumen-protected methionine through the dry period has been shown to improve dry matter intake and energy-corrected milk yield in early lactation cows. Transition cows undergo metabolic and physiological changes as they calve and enter lactation. While negative energy balance is commonly referenced, lactating cows also experience a period of significant negative metabolizable protein balance. Not only are cows mobilizing fat, but they are also breaking down muscle. Methionine has a role in numerous metabolic pathways, including pathways involved in lipid metabolism, inflammation and oxidative stress, making supplemental methionine a logical choice to consider for transition cows.

Heat stress: Researchers at the University of Illinois found that supplementing rumen-protected methionine to cows exposed to heat stress resulted in improved milk fat percentage compared to control cows not receiving supplemental methionine.

When evaluating your return on investment from supplementing rumen-protected amino acids such as methionine, it is important to recognize that the benefits can go beyond an improvement in milk protein. In addition to increases in milk fat yields, long-term benefits for cow health and reproduction can also be achieved. Not all herds are created equal, and certain bottlenecks and herd dynamics can elicit different results. Work with a nutritionist to determine what strategies work best for your dairy.

Barry Visser is a nutritionist for Vita Plus.


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