Feeding Rumen-Protected Choline To Transition Dairy Cows
F. S. Lima, B. A. Barton, and J. E. P. Santos, Univesity of Florida, Gainesville, Balchem Co., New Hampton, NY.
Objectives were to determine the effects of feeding rumen-protected choline (RPC) on hepatic tissue composition and hepatic lipidosis in dairy cows. Holstein cows, 46, 20 multiparous and 26 primiparous, were fed either 0 (n = 25) or 60 g of RPC to deliver 15 g/d of choline (n = 21; Reashure, Balchem) top dressed onto the diet once daily from 25 d prepartum to 80 d in milk (DIM). Blood was sampled at 1 and 14 d postpartum and analyzed for concentrations of 3-OH-butyrate (BHBA). Hepatic tissue collected by percutaneous biopsy at 9 DIM was analyzed for concentrations glycogen, triglycerides and dry matter (DM). Cows were categorized as having hepatic lipidosis if hepatic triacylglycerol concentration was > 5% on a wet basis. Data were analyzed using the Mixed and Logistic procedures of SAS and odds ratios (OR) and 95% confidence intervals (CI) were calculated. Concentrations of BHBA were similar (P = 0.53) for cows fed control and RPC at d 1 (1012.7 ± 137.5 vs. 836.6 ± 143.4 mMol) and d 14 (927.0 ± 137.5 vs. 926.3 ± 143.3 mMol) postpartum. Concentration of glycogen in hepatic tissue was similar (P = 0.35) for cows fed control and RPC (0.94 ± 0.15 vs. 1.14 ± 0.16 %). Similarly, concentration of triglycerides in the hepatic tissue did not differ (P = 0.31) for cows in the control and RPC diets (5.9 ± 1.2 vs. 4.1 ± 1.3%); however, concentrations of triglycerides on a DM basis tended (P = 0.10) to be greater for control than RPC cows (10.4 ± 1.7 vs. 6.0 ± 1.9%). Feeding RPC reduced the risk (OR = 0.23; 95% CI = 0.05, 1.06) of cows to have hepatic lipidosis (40.0 vs. 14.3%; P = 0.05). Concentrations of glycogen in hepatic tissue declined as concentrations of triglycerides increased (glycogen % = 1.251 – 0.04451 × triglycerides%; r2 = 0.11, P = 0.01). Feeding rumen protected choline reduced triglyceride concentration in liver DM tissue and the risk of hepatic lipidosis in early lactation dairy cows.
