Positive effects in dairy cows
Using protected choline chloride is an excellent way to support liver function in the transition dairy cow. During early lactation, choline appears to be a limiting nutrient for high milk production and supplementing rumen bypass choline chloride helps maximise milk production in dairy. Several studies show milk yield improvements, with an approximate 7% increase in milk production.
As explained by the important role of choline in the formation of VLDLs, it is also shown that protected choline chloride helps to avoid fatty liver syndrome. Especially in ‘at risk’ cows (fat cows prepartum), additional choline is beneficial in terms of supporting the fat metabolism and to encourage the transport of triglycerides out of the liver.
Another typical metabolic disorder in transition dairy cows is ketosis. As mentioned, incomplete oxidation of NEFAs in the liver leads to the formation of ketones (e.g. BHBA), which will appear in the blood, urine and milk.
High ketone levels in the blood (> 1,2mmol/ℓ) can result in clinical disease (clinical ketosis) with symptoms of decreased feed intake, a drop in milk production, weight loss and nervous symptoms. Also, subclinical ketosis, when ketone levels in the blood are elevated but clinical symptoms are less obvious, leads to economically important production losses.
The incidence of subclinical ketosis in dairy herds can be high (20 to 30%), which results in reduced milk yield and also in direct costs associated with the higher susceptibility to diseases. The prevalence of both fatty liver disease and (subclinical) ketosis can be reduced with the preventive use of protected choline chloride, which reduces the costs incurred by these metabolic diseases.
Thanks to these beneficial effects that lead, depending on the situation, to a decrease in direct and indirect costs and an increase in milk yield and reproductive performances, protected choline chloride will result in an economic benefit for the cow herd.
Choline requirements for dairy are not established (NRC, 2001), but high-producing cows excrete 3 to 5g/day of choline in the milk. It appears that a minimal daily supplementation of 10g of bioavailable choline chloride is needed to see significant results. In several studies, dosages of 15g are used and these amounts of choline chloride should therefore be recommended.
As for good rumen stability of choline chloride, the fat coating should be protective enough. Typically, products contain around 25% of the active ingredient. Consequently, recommended supplementation of rumen protected choline chloride is 60g/cow/day.
It is especially advised to supplement choline chloride during the transition phase. It is advised to start from approximately three weeks prior to the expected calving date and to supplement cows until three to six weeks post-calving. If herds are experiencing problems later during lactation, a longer supply should be considered (e.g. the first 90 days of lactation).
Because choline is so important in the synthesis of VLDLs and the methylation of other compounds, a good choline supply is required for exporting fats from the liver and for the optimal functioning of the liver in general.
Although dairy cows can endogenously produce choline, the availability of this nutrient will be inadequate for maximal performance. Supplementary choline chloride has proved to have beneficial effects, but only if it is protected against degradation in the rumen. Supplementation leads to higher milk yields and prevents metabolic disorders such as ketosis and fatty liver. In nutritional strategies to lower problems in transition cows, good rumen protected choline chloride certainly deserves its place.