Update on Rumen-protected Choline in Dairy Cow Nutrition

Choline is a quasi-vitamin that has a variety of functions in mammalian metabolism. Its major functions are as the predominant phospholipid contained in the membranes of all cells in the body (as phosphatidylcholine), a component of the neurotransmitter acetylcholine, and as a direct precursor to betaine in methyl metabolism. It is beyond the scope of this paper to review these functions in depth; however, excellent reviews have been published within the past several years that provide substantive overviews of choline metabolism with orientation to the dairy cow (Donkin, 2002; Pinotti et al., 2002). The purpose of this paper is to provide a focused review on the potential for application of rumen-protected choline during the transition period of dairy cows with the end goal of improving transition period success. Furthermore, I will review recent information on the role of choline in reproductive performance. Finally, I will comment on the future of choline as a nutrient in dairy cattle nutrition.