Effects of High Amounts of Dietary Choline Supplementation on Duodenal Choline Flow and Production Responses of Dairy Cows

Abstract

At low amounts of supplementation, dietary choline as choline chloride is rapidly degraded in the rumen. Two experiments were conducted to investigate whether the bacterial choline degradation in the tureen of dairy cows could be overwhelmed. Holstein cows were fed total mixed rations containing 40% corn silage and 60% concentrate on a DM basis with treatments of 0, 10, and 20 g added choline/kg ration DM fed in a Latin square design. In Experiment 1, using three ruminally and duodenally cannulated, late lactation cows, increasing dietary choline intake from 23 to 326 g/d increased duodenal choline flow from 1.2 to 2.5 g/d, indicating a very low recovery of added dietary choline. In Experiment 2, with 18 midlactation cows, increasing choline from 18 to 282 g/d reduced feed intake from 18.4 to 16.7 kg/d. Milk composition was unaffected, and milk production tended to decrease with increasing dietary choline. High amounts of added choline reduced feed intake and did not improve milk production of cows.