233 Efficacy of fat-embedded calcium gluconate on lactation performance in dairy cattle

Several beneficial effects have been observed in the gastrointestinal tract in response to the provision of short-chain fatty acids such as butyrate, including the improvement of gut barrier function, stimulation of epithelial cell proliferation and gastrointestinal homeostasis. By improving gut barrier integrity, it is possible that less energy would be spent mounting an immune response against infiltrating xenobiotic compounds, allowing for more energy to be partitioned towards productive activities, such as milk synthesis. Previous work has demonstrated that gluconic acid and its salts have a prebiotic effect in the lower gut in monogastric animals, where it acts as a substrate for butyrate synthesis, with new data suggesting a similar response in dairy cattle. The objective of this study was to evaluate the effects of supplementation of a fat-embedded calcium gluconate product on milk production in dairy cattle. Lactating heifers (n = 22) and cows (n = 53) were offered either a total mixed ration supplemented with 0.07% fat-embedded calcium gluconate or a negative control ration over the course of a full lactation. Milk production and dry matter intake were recorded daily, while milk composition was determined at regular intervals over the lactation. Cows receiving the supplement displayed significant (P ≤ 0.046) increases in milk and component yields, while consuming 1 kg DM/d more during lactation compared to control. Heifers receiving the supplement displayed decreased (P ≤ 0.044) yield of milk fat and fat-corrected milk, 0.09% increased milk protein content, and decreased feed efficiency. Overall, the results in multiparous animals are consistent with previous work examining calcium gluconate. Further work is needed to characterize the differential response in heifers.