Enhancing productive performance in dairy cows through supplementation of a blend of essential oils and Saccharomyces cerevisiae

This study evaluated the DM and nutrient intake, apparent total-tract digestibility, feed particle sorting, milk yield and composition, blood metabolites, rumen fermentation, and nitrogen balance of dairy cows supplemented with essential oils, alone or in combination with live yeast. Forty-two Holstein cows (177 ± 56.0 DIM, 36.4 ± 5.26 kg/d milk yield, 630 ± 121.0 kg BW; 18 primiparous and 24 multiparous) were grouped into 14 blocks based on DIM, milk yield, BW, and parity, and assigned to the following treatments: (1) control (CON); (2) blend of essential oils (BLD), containing coriander (Coriandrum sativum) seed oil, eugenol, geranyl acetate, and geraniol, fed at 1 g/cow per day (Agolin Ruminant, Agolin SA); or (3) BLD + yeast (BLDY), composed by BLD fed at 1 g/cow per day + Saccharomyces cerevisiae, fed at 2 g/cow per day (Yea-Sacc, Alltech). Cows were subjected to a 2-wk covariate period and treatments were provided during the following 9 wk. Data were analyzed as repeated measures modeling the fixed effects of treatment, time, and their interaction, and the random effect of block. Covariate measures were included in the model as fixed effects and treatment means were compared through orthogonal contrasts (CON vs. BLD + BLDY and BLD vs. BLDY). Dry matter and OM intake were greater and NDF digestibility tended to be higher in cows fed additives (BLD + BLDY). Additionally, feed additives resulted in higher milk yield, fat- and energy-corrected milk yield, and milk fat, protein, and lactose yields, as well as lower nitrogen concentration in urine. Within the supplemented groups, BLDY showed lower crude protein intake and BUN concentration, and tended to have higher OM digestibility compared with BLD. No significant differences were observed in ruminal pH, ammoniacal nitrogen or VFA among the treatments. These results suggest that BLD, alone or combined with live yeast, positively affected overall performance in lactating cows, although no significant effects were observed on rumen fermentation.