PSXII-42 The lactational response in dairy cows to supplementation of calcium gluconate embedded in a fat matrix
Abstract Functional nutrients that facilitate gastrointestinal health may serve as an alternative to the use of antimicrobials in animal production systems. Gluconic acid has been used as a prebiotic health promoter in non-ruminant applications. It is poorly absorbed in the small intestine and is fermented to butyrate in the lower gastrointestinal tract. The gut health benefits of butyrate have been demonstrated in both non-ruminant and ruminant models, but effects of post-ruminal gluconic acid supplementation are not well described. The objective of this study was to determine the effects of calcium gluconate embedded in a fat matrix (CGFM; 40% CaGlu) on dry matter intake, blood metabolites, milk production and fecal short chain fatty acid (SCFA) production in early lactation dairy cows (21 ± 2 DIM) fed to 100% of energy and protein requirements. The experiment was a 3 x 3 replicated Latin square with 13 replicates (3 cows/replicate), 3 experimental periods (each 28 d) and 3 dietary treatments of control (0 g/d), 16 g/d and 25 g/d of CGFM. There was no treatment effect on DMI and milk yield. The relationship between dose of CGFM (i.e. 0, 16, 26 g/d) and milk fat and protein yield, energy corrected milk was significantly quadratic (P < 0.05) while feed efficiency tended to be quadratic (P = 0.08). The greatest response was in milk fat yield, which increased 90 g/d over control at 16 g/d of CGFM. No significant changes in blood metabolite concentrations or fecal SCFA concentrations were observed between treatments, although there was a numerical increase in non-esterified fatty acid concentration in response to the 16 g/d CGFM dose (P = 0.16). The response to supplementation of fat-embedded calcium gluconate appears to alter energy partitioning in the lactating dairy cow, as demonstrated with subtle changes in circulating lipid and increased fat yield.