
Research Note
Amino Acids:
Supporting Transition & Reproduction
Ongoing research is dissecting the multiple roles of dietary amino acids in supporting a smooth transition into lactation and improved reproductive performance. Studies going back a decade or more point to the potential of rumen-protected methionine (RPM) and lysine (RPL) to increase milk yield and milk protein synthesis.
However, more recent studies show how RPM in particular helps in formulating close-up diets to limit total energy. Post-calving, it works to support optimal nutrition in transition, helping to avoid negative energy balance (NEB).Ā Ā
Dr. Phil Cardoso at the University of Illinois has noted that the most severe NEB correlates with peak post-calving disease incidence. It also correlates with the peak in blood concentrations of non-esterified fatty acids (NEFA) and the fastest increase in milk yield. Other researchers have connected postpartum NEB to poorer reproductive performance.
The biology of dairy cows requires “metabolic decisions” about where to direct scarce resources, Cardoso has pointed out, “and in early lactation, nutrients will be directed to milk production rather than to the next pregnancy.”
The Cardoso lab investigated dietary supplementation with methionine during the final stages of follicular development and early embryo development, up to day seven after breeding. During that time, prior to attachment, the embryo is free-floating and depends upon uterine secretions for energy and the “building blocks” for development, including amino acids. The Cardoso lab studies showed that methionine supplementation increased lipid accumulation in the embryo.
“Methionine supplementation seems to impact the preimplantation embryo in a way that enhances its capacity for survival because there is strong evidence that endogenous lipid reserves serve as an energy substrate. The lower pregnancy losses from cows fed a methionine enriched diets suggest that methionine favors embryo survival, at least in multiparous cows.”
Lysine supplementation also may begin to play a larger role in a smooth transition because the high-producing cow experiences systemic inflammation during transition. Cardoso has pointed to previous work on post-calving innate immunity, which is affected by amino acid supply.
Though the studies are limited, “there is evidence of decreased inflammatory response upon supplementation of RPL through the transition period.”
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