Increasing doses of biocholine on apparent digestibility, ruminal fermentation, and performance in dairy cows

Abstract

Biocholine is an herbal feed additive considered a natural alternative to synthetic choline, with relatively low rumen degradability composed of cellulose and choline conjugates, namely phosphatidylcholine. Rumen-protected choline has been largely evaluated during the peripartum period, but few studies evaluated the effects of choline supplementation after the transition period. The objective of this study was to determine the effects of increasing doses of biocholine on feed intake, feed particle sorting, total apparent digestibility, ruminal fermentation, milk yield and composition, purine derivative excretion, and nitrogen balance. Twenty-four Holstein cows (163 ± 98 days in milk, 27.6 ± 7.14 kg/d milk yield), 4 of which were ruminally cannulated, were enrolled to this study. Cows were blocked according to milk yield, days in milk, and presence of ruminal cannulas, then all cows were randomly assigned to a treatment sequence in a replicated 4 × 4 Latin square experiment design. The experimental treatments were a control (CON) diet, and biocholine (BC; Biocholine FC®, Nutriquest Technofeed Nutrição Animal Ltda., Campinas, Brazil) fed at 7, 14, and 21 g/d. Cows were allowed 14 d of adaptation to treatments and the last 7 days of each period were used for sampling. The forage to concentrate ratio of the basal diet was 48:52 (on a dry matter basis) with corn silage as the single forage source, and diet was provided in the form of total mixed ration. No treatment effects were detected on feed intake, but BC quadratically affected (P = 0.010) sorting for feed particles >19 mm and linearly increased (P = 0.037) ether extract digestibility (840, 834, 843, and 853 g/kg for cows fed BC at 0, 7, 14, and 21 g/d, respectively). Biocholine supplementation tended to quadratically decrease ruminal pH (6.17, 6.04, 6.11, and 6.11 for cows fed BC at 0, 7, 14, and 21 g/d, respectively) but had no effect on concentrations of total volatile fatty acids and NH3-N. Biocholine had a positive quadratic effect (P ≤ 0.042) on milk yield (29.5, 30.5, 30.0, and 29.8 kg/d for cows fed BC at 0, 7, 14, and 21 g/d, respectively) and feed efficiency (1.20, 1.25, 1.21, and 1.21 kg milk/kg DM intake for cows fed BC at 0, 7, 14, and 21 g/d, respectively). Biocholine tended to quadratically affect (P = 0.058) N excretion through milk (157, 162, 160, and 159 g/d for cows fed BC at 0, 7, 14, and 21 g/d, respectively). There was no evidence for treatment effects on purine derivatives excretion. In conclusion, feeding BC may improve milk yield and feed efficiency of dairy cows. Predicted maxima response in milk yield and feed efficiency were observed at 10 g/d of BC.