When profit margins tighten, many dairy producers look for ways to reduce expenses.

Protein is a relatively expensive nutrient. Efficiently using dietary protein may improve profitability. But remember, cows do not have a requirement for protein. They require amino acids, the building blocks of protein. The essential amino acids must be supplied in the diet. Of the 10 essential amino acids, lysine and methionine are first-limiting in lactation diets. They must be delivered at adequate levels and in the proper ratio to one another – otherwise production can be affected. When the right balance of amino acids is reached, all dietary proteins can be used more efficiently and milk production and component levels can increase.

Using conventional feedstuffs to meet lysine and methionine requirements often leads to the overfeeding of total protein, an unnecessary expense and a practice that harms the environment. The introduction of commercial rumen-bypass methionine products allowed nutritionists to more efficiently meet the methionine needs of cows. The recent introduction of a rumen-bypass lysine heightens the level of precision possible in ration protein formulation. With rumen-bypass lysine, producers often see improved milk production and components while feeding equal or lower ration protein levels.

Profit potential
The higher the premium producers receive for milk protein and butterfat, the more attractive balancing for these first two limiting amino acids becomes. Research has shown that feeding optimum levels of lysine and methionine in the right ratio allows for higher milk production and milk protein yield, increases the efficiency of protein use by the cow and reduces the excretion of nitrogen into the environment.

Formulating diets for amino acids is common in the poultry and swine industries due to increased production efficiencies and profitability. Dairy had lagged behind these industries, waiting for a commercially available lysine that could escape rumen degradation and be available for absorption in the intestine. Rumen-bypass lysine is now available and benefitting dairy producers who know how to use it.

Lysine sources
While rumen-bypass methionine products have been available for two decades, a concentrated source of lysine that could consistently bypass the rumen for absorption in the intestine had eluded the industry until now. The first rumen-bypass lysine was introduced in 2008 and has dramatically increased precision in amino acid balancing. Before, nutritionists had primarily used animal proteins to increase ration lysine levels. The lysine level and bioavailability in animal protein sources, however, vary considerably. The lysine in blood meal, for example, has been shown to range from 7.01 percent to 9.02 percent of protein with intestinal digestibility values varying from 17 percent to more than 94 percent, as determined in rats.

This variability in animal sources of lysine is due in part to lysine’s susceptibility to heat damage during processing. Researchers have noted that both temperature and duration of exposure to heat influence the quality of animal proteins. Animal protein sources include meat and bone meal, meat meal, fish meal, hydrolyzed feather meal and blood meal.

Impact on dairy
Before, inconsistency in the level and availability of lysine could hurt profitability. Underestimating lysine availability can result in overfeeding protein. This can be expensive, particularly when using animal proteins as lysine sources. Overestimating lysine availability can result in underfeeding lysine, which leads to lower performance and lost income.

Milk production and milk protein respond to increasing lysine levels, assuming that the methionine levels are adequate. Increasing a lysine-deficient diet by just 1 gram of metabolizable lysine can mean an increase of approximately 0.38 pounds of milk and 0.014 pounds of milk protein.

For the sake of demonstration, the lysine values for three blood meals and a commercially available rumen-bypass lysine are reported as a percentage of metabolizable protein in Table 1. Blood meal A is an estimate based on National Research Council (NRC) 2001 values. Blood meals B and C are based on values actually measured and reported in the Journal of Dairy Science.

If the source of blood meal in the ration is assumed to be equal to sample A but is comparable to either B or C, then poorer-than-expected performance will result because less lysine is available for milk and milk protein production. A concentrated and consistent source of rumen-bypass lysine minimizes variation in dietary metabolizable lysine and in the resulting performance. Approximately 45 grams of rumen-bypass lysine consistently supplies an amount of metabolizable lysine equivalent to a half pound of good quality, ring-dried blood meal with the added benefit of creating space in the diet for other critical nutrients.

Cost benefits
What is the best time to begin balancing for amino acids? Right now, especially if you receive a premium for milk protein or butterfat. Even as milk prices hover between $9 per hundredweight to $10 per hundredweight, producers can see a significant return on investment by properly balancing rations for amino acids. When milk protein reached $4 per hundredweight in some areas in 2008, interest in amino acid balancing reached new heights. (See Table 2.)

Formulating for amino acids has never been easier. Today’s ration formulation software programs streamline the process. Use these four steps.

1. Formulate for a minimum target level of metabolizable protein (MP) to ensure that the cows’ need for all amino acids, except lysine and methionine, are met.

2. Optimize methionine within the MP by using rumen-protected methionine sources to the target level – 60 to 62 grams.

3. Balance up for a target level of lysine using a rumen-protected lysine source, according to the methionine level achieved – 180 to 185 grams.

4. Adjust the levels of methionine and lysine to maintain a methionine-to-lysine ratio of 3-to-1.

The solid return on investment from balancing for amino acids makes it a valuable management tool year in and year out, even tough times like the present. PD

References omitted but are available upon request at editor@progressivedairy.com

Glen Aines
Technical Services
Balchem Animal Nutrition
gaines@balchem.com