Feeding rumen-protected Capsicum oleoresin to dairy cows during the transition period and early lactation: Effects on nutrient digestibility, blood metabolites, and performance

Capsicum oleoresin (CAP), a plant extract derived from chili pepper plants, contains bioactive compounds reported to influence the energy metabolism in dairy cows. This study investigated the effects of feeding rumen-protected CAP during the transition period and early lactation on total-tract apparent digestibility of nutrients, serum metabolites [glucose, urea-N, non-esterified fatty acids (NEFA), and beta-hydroxybutyrate (BHB)], and milk yield and composition in dairy cows. Twenty-four healthy Holstein cows (12 multiparous and 12 primiparous) were enrolled to this study at − 4 wk from the expected calving date. Animals were blocked according to parity and expected calving date. Cows within block were randomly assigned to a control (CON) treatment without feed additives or to the CAP treatment, dietary supply of rumen-protected CAP at 100 mg/d. Pre-partum and post-partum data were analyzed separately. Dry matter intake and related dietary variables were not affected by treatments during the pre- or post-partum period. No differences were detected on digestibility of DM, organic matter, or crude protein during the pre-partum and post-partum periods. Serum metabolite concentrations were similar between treatment groups either during the pre-partum or post-partum periods. Milk yield tended to be greater (P = 0.07) in cows fed CAP than CON (31.7 and 28.5 kg/d, respectively). Fat-corrected milk yield was increased (P = 0.03) by feeding CAP. Milk fat yield (1.20 vs. 1.05 kg/d) and feed efficiency (1.72 vs. 1.50 kg milk/kg DM intake) were significantly greater (P ≤ 0.03) in cows fed CAP than CON. Feeding rumen-protected CAP at 100 mg/d during the transition period and early lactation increased fat-corrected milk yield, and improved milk fat and feed efficiency of dairy cows.