The aim of the current study was to assess the effect that supplementation with yeast culture plus enzymatically hydrolyzed yeast (YC-EHY) during the transition period and lactation had on the performance, somatic cell count (SCC), and metabolic profile of dairy cows. Thirty multiparous Holstein dairy cows were divided into two groups. The treatments were 0 supplementation (control) and supplementation with 28 g/cow/day of YC-EHY. The supplementation began 35 ± 5 days before the expected calving date. The cows were kept in their respective treatments for 50 days after the calving date. Body condition score (BCS), body weight, milk composition, SCC, and milk yield were assessed on a 2-weekly basis. Plasma samples were collected on days - 21st, - 7th, 0, 3rd, 7th, and weekly thereafter until 42 days postpartum and analyzed for albumin, β-hydroxybutyrate (BHBA), urea, and non-esterified fatty acids (NEFA). There was an effect of treatment on milk yield in the supplemented animals in comparison to the control group (27.88 ± 0.98 vs 24.58 ± 0.99 kg/days, P = 0.03). There was no effect of treatment (P > 0.05) on variables like 3.5% fat-corrected milk (FCM) and energy-corrected milk (ECM), milk component (%), milk composition yield (kg/day), and SCC. There was an interaction between group × days on ECM (P = 0.04) and protein (P = 0.008). The supplementation had no effect on the analyzed metabolites and on body weight and BCS. The supplementation with YC-EHY during the transition period and lactation improved milk yield without altering the metabolic profile.
Keywords: Hydrolyzed yeast; Metabolism; Milk yield; Transition period.