Any response to dietary supplementation of choline in ruminants would depend on factors such as age, level of productivity, sulfur amino-acid status and other choline-sparing nutrients. Folic acid, vitamin B12 and manganese status affect choline metabolism and absorption. Supplemental choline has been shown to be beneficial to young ruminants (e.g., young calves, prior to ruminal development). For lactating dairy cows or other ruminants that may be marginal in choline supply, a rumen-protected choline source is required to consistently increase plasma choline levels. Studies to date with rumen-protected or abomasally infused choline have shown varying responses in dairy cows, although milk production has been increased in three studies. Response to choline by feedlot cattle has also been a mixture of positive and no response. The decision whether to fortify rations with choline will depend on assessment of diet, production level or rate of growth, and projected return on investment.
Choline chloride is itself stable in multivitamin premixes but highly destructive of vitamins in the premix (Frye, 1978; Gadient, 1986). This is due to both the high reactivity and the hygroscopicity of choline. Choline is stable during feed processing and storage in pelleted and extruded feeds.
