PSI-12 - Effects of supplementing propionate in a finishing diet on dry matter intake, glucose clearance, and blood metabolites

The objective of this experiment was to determine if supplementing propionate alters DMI, glucose clearance rate, and blood metabolite concentrations in steers fed a finishing diet. Holstein (n = 15) steers were individually fed a finishing diet ad-libitum. Steers were allocated by BW to receive: no Ca propionate (CON), 100 g/d (LOW), or 300 g/d (HIGH) in the diet. Orts were collected and weighed daily to determine DMI. Blood samples were collected on d 0, 7, and 21, and BW recorded on d 0, 14, and 28. A glucose tolerance test was conducted on d 14 and 28 of the trial. Samples were analyzed for whole blood glucose and lactate, and plasma NEFA. Data were analyzed using a mixed model with treatment, day and their interaction included, with day as a repeated measure. The CON treatment had greater (P < 0.01) DMI than LOW and HIGH. BW was greater for CON throughout the experiment and all treatments had an increased BW on day 28 (P = 0.03 for the interaction). Whole blood glucose concentrations tended (P = 0.09) to be higher on d 21 than d 0 and 7, but was not affected by treatment (P = 0.58). Plasma NEFA concentrations were lower (P = 0.05) for CON than other treatments, and greater (P = 0.002) on d 0 than d 7 and 21. Whole blood lactate concentrations were greater (P = 0.05) on d 7, than d 0 and 21, but was not effected by treatment (P = 0.13). There was no treatment (P ≥ 0.16) or day effect (P ≥ 0.36) on glucose peak, plateau, or clearance rate. These data indicate that supplemental propionate may decrease dry matter intake but might not alter glucose clearance rate.