title: Effects of dietary and abomasally infused choline on milk production responses of lactating dairy cows.
abstract: Three experiments investigated the effects of exogenous choline on milk production responses of dairy cows. Ruminally fistulated Holstein cows were fed total mixed diets containing 30% corn silage and 70% corn/soybean meal-based concentrate in experiment 1, or 40% corn silage and 60% concentrate in experiments 2 and 3. In experiment 1, the effects of unsupplemented (control), dietary supplemented choline (50 g/d) and abomasally infused choline (50 g/d) were examined using three first-lactation cows in a 3 X 3 Latin square design. While dietary added choline had no effect, abomasally infused choline increased daily milk and 4% fat-corrected milk yield 3.2 and 3.8 kg/d respectively. In experiment 2, effect of daily abomasal infusion of 0, 30, 60 and 90 g choline were studied using four mature cows in a 4 X 4 Latin square design. Fat-corrected milk and milk fat percent were 2.6 kg/d and 0.59 percentage units higher for cows infused with 30 g/d choline than for unsupplemented controls, with 60 and 90 g/d choline infusions showing smaller effects. In experiment 3, daily abomasal infusion of 0 or 40 g choline were studied using four mature cows in a switchback design. Choline infusion (40 g/d) increased daily milk 1.6 kg/d over control while having no effect on milk composition or feed intake. Results of these experiments suggest a possible requirement for supplementing choline in lactating dairy cows.
authors.affiliation: Animal Sciences Department, University of Maryland, College Park 20742.
authors.forename: B K
authors.initials: BK
authors.lastname: Sharma
authors.forename: R A
authors.initials: RA
authors.lastname: Erdman
mesh_terms: D000018:Abomasum; D000818:Animals; D002417:Cattle; D002794:Choline / Q000008:administration & dosage / Q000494:pharmacology*; D004032:Diet; D004041:Dietary Fats / Q000032:analysis; D004435:Eating / Q000187:drug effects; D005260:Female; D007441:Intubation, Gastrointestinal / Q000662:veterinary; D007774:Lactation / Q000187:drug effects*; D008892:Milk / Q000032:analysis; D008894:Milk Proteins / Q000032:analysis; D011247:Pregnancy
chemical_list: D004041:Dietary Fats; D008894:Milk Proteins; D002794:Choline