Abstract #T160

# T160
Effect of calcium salts of medium-chain fatty acids on performance and plasma hormone concentrations in lactating dairy cows.
S. Ishimaru*1, T. Hasunuma2, K. Kawashima3, T. Yamaguchi3, S. Asakuma4, S. Kushibiki5, T. Obitsu1, T. Sugino1, 1The Research Center for Animal Science, Graduate School of Biosphere Science, Hiroshima University, Higashi-Hiroshima, Japan, 2Toyama Prefectual Agricultural, Forestry &Fisheries Research Center, Toyama, Japan, 3Chiba Prefectural Livestock Research Center, Chiba, Japan, 4Hokkaido Agricultural Research Center, Sapporo, Hokkaido, Japan, 5National Institute of Livestock and Grassland Science, Ibaraki, Japan.

This study aimed to evaluate the effect of calcium salts of medium-chain fatty acids (MCFA) on milk production performance and plasma hormone concentrations in lactating dairy cows. Fifteen multiparous Holstein cows (initial days in milk: 183 ± 15.2, parity: 2.9 ± 0.2, initial BW: 674 ± 15.9 kg) were managed in freestall barns, provided experimental diets twice daily, and milked before each feeding. Cows were fed a total mixed ration (TMR) containing 3.3% ether extract (EE), 37.0% NDF and 1.72 Mcal/kg NEL on a dry matter (DM) basis. Cows were randomly assigned to dietary treatments using a replicated 3 × 3 Latin square design with 21-d periods. Three treatments were arranged as control, 0.5% and 1.0% MCFA. Calcium salts of medium-chain fatty acids containing 80% caprylic acid and 20% capric acid was added to the TMR at 0.5 and 1.0% of DM intake (DMI), respectively. Milk samples were collected on the last 3 d and blood and rumen samples were collected on the final day of each treatment. Repeated measure ANOVA tests were performed to determine effects of treatment using the PROC MIXED procedure of SAS. Ruminal fermentation, DMI, BW, BCS, milk yield and composition, or plasma metabolite (glucose, nonesterified fatty acids, triglyceride and total-cholesterol) concentrations were not affected by MCFA. Entodinium spp. counts in the rumen were lower (P = 0.05) with 1.0% MCFA (4.83 ± 0.08; LSM ± SE) compared with those in the control (5.05). Relative plasma ghrelin levels were higher (P = 0.04) with 1.0% MCFA (1.48 ± 0.17) than with the control (1.00). Relative plasma IGF-1 levels were higher (P = 0.03) with 1.0% MCFA (1.03 ± 0.03) than with 0.5% MCFA (0.91). In addition, relative plasma insulin levels were higher (P = 0.02) with 0.5% MCFA (1.87 ± 0.24) than the control (1.00). The insulin: glucagon ratio tended to be lower (P = 0.14) with 1.0% MCFA (1.64 ± 0.55) than with the control (2.39) or with 0.5% MCFA (2.77). In conclusion, MCFA has the potential to shift nutrient metabolism toward a catabolic state via alterations of plasma hormone dynamics in lactating dairy cows.

Key Words: medium-chain fatty acids, ghrelin, metabolic hormone