Amino acid balancing: Benefits go beyond components

Posted on September 10, 2020 in Dairy Performance
By Dr. Eric Schwab
The classically discussed benefits of amino acid balancing are typically increases in milk component yield (via increases in both component content and output), reduced metabolizable protein (MP) required, and increased efficiency of protein use. This focus is understandable as these benefits are the easiest to quantify economically.

However, recent research shows that these most tangible benefits are not the only reasons why amino acid nutrition should be adopted.

Lower herd turnover
Cornell University and University of Wisconsin-Madison researchers teamed up to evaluate the effects of pre- and postpartum methionine supplementation on health, productive, and reproductive performance.  A total of 570 cows were enrolled in this experiment between both universities. Methionine was supplemented, or not, from 21 days before expected calving until 147 days post-calving.  Each group was composed of 235 cows, with each university having both control and treatment cows.

In addition to the usual milk component responses (+0.12% units milk protein and +0.10% units milk fat) that are observed, herd exits were also impacted by methionine supplementation.  Over the complete lactation, 20.6% of the control cows exited the herd whereas 13.4% of the methionine-supplemented cows exited.  For a 500-head herd, that’s a difference of about 35 head that you can apply to some economic and management scenarios.

How could this be? Interestingly, part of the answer could be that, for any of the cows that had one or more recorded disorders, time to confirmed pregnancy for the methionine-supplemented cows was about one heat cycle less.  As we all know, better reproduction and reduced herd turnover often go hand-in-hand.

Benefits for calves
Calves also benefit from supplemental methionine – even before they are born!

University of Illinois researchers found that calves whose dams were supplemented with methionine pre-calving were heavier and taller at the hips and withers at birth. Those are in utero effects.  Likewise, average daily gains through nine weeks post-birth were also higher.

Why is it that supplementation of methionine could have these effects? Improved health? In utero effects on the fetus?

While analogous effects have been observed for decades in pigs and poultry, it’s often hard to make the leap from those non-ruminant species to cattle. After all, our critters have rumens that produce large quantities of microbes that are used as MP. But, when it comes to methionine (which is one of the essential amino acids not produced in appreciable quantities by a cow’s metabolic machinery), even microbial protein isn’t enough for maximal production. Answers to why some of these benefits were observed lie in some influences on basic metabolism.

The same University of Illinois researchers took a deep dive into how methionine influences gene-level functioning of both the transition cows and calves mentioned above. All of this gets into some intense science involving genes, enzymes and a whole bunch of acronyms that can really make your head spin. I’ll spare the gory details, but the punchline to these evaluations is that cows and calves that were supplemented with methionine experienced changes in their basic metabolism that reflect increased efficiency of not only protein use (specifically amino acid use), but also energy metabolism. Indicators of immunological function, inflammation, antioxidant status, and liver health and function were also improved.

Great strides are being made in painting the whole picture of the benefits of amino acid nutrition in dairy cattle. The evidence shows that improvement in component output is just one part of the story.

About the author:  Dr. Eric Schwab grew up in a rural town in New Hampshire.  He attended the University of New Hampshire–Durham, where he received bachelor’s degrees in dairy management and environmental and resource economics in 1998.  While working in northeast Wisconsin, he met Dr. Randy Shaver and returned to academia at the University of Wisconsin-Madison to pursue his graduate degrees.  In Shaver’s lab, Schwab’s master’s degree research focused on kernel processing and chop length in BMR corn silage.  His Ph.D. dissertation focused on B-vitamin nutrition and ruminal B-vitamin synthesis in lactating dairy cows.  In September 2005, Schwab joined Vita Plus on the dairy nutrition and technical services team.  He lives in Deerfield, Wisconsin with his wife and their three sons.

Category: Animal health
Dairy Performance
Feed additives
Feed quality and nutrition
Transition and reproduction