The increasing value of milk protein pushed the price of milk paid to the dairy farmer to an all-time high in the beginning of 2014. This much-needed boost in price has been a long time coming, as the U.S. dairy industry has been slow to recognize the importance and potential of the world market for dairy products. Even though the pricing, trading and marketing of milk protein in its various forms are complex, the more milk protein dairy farmers can produce and ship, the more their milk will be worth.
Since the 1980s, dairy scientists and researchers have been focusing on how to improve the amount of milk protein that a cow produces. For many years, it was thought that increasing the amount of crude protein in a cow’s diet would also increase the amount of protein in her milk, but it doesn’t work that way. What research has determined is that the protein metabolism of a cow and the amount of protein ending up in milk is a complex process that involves both energy and amino acid metabolism.
As is so often the case, the focus of dairy cow nutrition is on what’s happening in the rumen. Much of the protein – and more correctly the amino acids – that a cow must metabolize has to come from the rumen in the form of the expended, deceased microbes that had been fermenting the feedstuffs. The protein profile of these microbes just happens to be very close to the profile of milk protein. However, the protein coming from just the rumen bugs is not nearly enough to meet the high milk production needs of our modern dairy cows.
Research has determined that dairy cow diets are often deficient in lysine and methionine, two essential amino acids. The microbial protein that escapes the rumen already has the optimal lysine and methionine levels. If more microbial protein is created in a healthy rumen, then more of the well-balanced protein makes it to the small intestine for absorption.
The balance of the amino acids that are absorbed in the small intestine must come from the proteins that are found in the feedstuffs themselves. However, most feedstuffs offered to our cows – corn and corn byproducts, wheat byproducts, brewers’ grains and sugar beet pulp – all come up short of having the proper amino acid profiles. Additionally, with the variability of the degradable amino acids in feedstuffs, it’s been, at best, an educated guess as to the actual levels of any amino acids that come from feedstuffs, making it difficult to balance for absorbable amino acids.
In recent years, scientists have made a breakthrough by creating rumen-protected methionine and lysine products that deliver a predictable level of those amino acids to the small intestine.
Feed trials over the past decade have confirmed that through the use of rumen-protected methionine, milk protein levels could be increased as long as there was a reliable lysine source available in the diet. However, nearly all of this lysine came from animal byproducts such as blood, meat and bone, as well as fish meal – expensive and variable. Several years ago, manufactured rumen-protected lysine products became available to dairy farmers and are showing promising results in delivering predictable levels of lysine to the small intestine.
For the dairy farmer, having rumen-protected lysine and methionine available for ration formulation has opened the door for increased milk production as well as improved milk components. Where it has often been a challenge to get milk protein levels in Holsteins over 3 percent, it’s now routine to have protein tests over 3.3 percent. That may not seem like a lot of improvement, but the math suggests otherwise.
If a cow is producing 70 pounds of milk with 3 percent protein, she’s producing 2.1 pounds of protein in the milk. If the test increases to 3.3 percent, she’s now producing 2.31 pounds of protein. If the price of milk protein is at $4 per pound (see chart), that will increase the value of the cow’s milk from $8.40 to $9.24; that’s an increase of 84 cents per cow per day. When diets are balanced even more precisely, with proper carbohydrate fractions and digestible forages, milk production will increase the potential revenue to over $1 per cow. That’s significant.
When rations are correctly balanced for lysine and methionine, dairy farmers can expect higher milk protein percentages and more milk production, as well as a reduction in the percentage of total crude protein (CP) in the ration, meaning less dietary protein lost in the manure. Methionine fortification often increases milk fat percentage as well. Increasing milk component percentages increases the value of the energy-corrected milk.
Virtually all milk cow rations that are correctly balanced with the use of rumen-protected lysine and methionine products have allowed for the reduction of CP in the ration. Where many high-producing diets in the past have regularly been formulated at 18 percent CP or higher, diets can now be lowered to 16 percent CP or less. This has the added positive effect of keeping excess nitrogen from finding its way into the environment, allowing for more proactive nutrient management.
In a component-driven marketplace where the protein price is high, balancing rations with optimal levels of lysine and methionine has been shown to be cost-effective. In most cases, the highest return on investment has been seen in the fresher cows, so it’s important and more cost-effective to be able to group cows according to stage of lactation to take full benefit of the increased milk revenues.