The effect of supplementing dairy cows with a hydrolyzed yeast product (Progut™Rumen) on milk production and somatic cell scores
The object of this study was to determine if supplementing Holstein-Friesian cows with hydrolyzed yeast product (Progut™Rumen) had an effect on milk production and somatic cell score (SCS). Holstein-Friesian dairy cows (n = 248) were balanced for DIM, pre-experimental milk yield, and milk composition and assigned to either a control (n =127) or hydrolyzed yeast (Progut, n = 121) treatment. Cows were put into two large pens and after each milking the cows were rotated into a new pen to account for environmental effects in the shed. Cows were individually fed the Control and Progut Rumen(10g/cow/day) treatments in the milking parlour during the morning milking. Therefore the cow was considered the experimental unit. The trial was carried out over two seasons (for a 10 wk period and a 8 wk period) and on weekly intervals milk yield was recorded and milk composition (fat yield and %, protein yield and %, lactose yield and %) and somatic cell score was determined. The dataset was divided in three ways for the analysis; the entire dataset, all cows with an average daily milk yield > 24kg, and finally all cows with an average daily milk yield > 30kg. All data were analyzed in SAS with a repeated measures mixed model with the appropriate covariance structure determined by Bayesian Information Criterion. The fixed effects included treatment, season, parity (1 to ≥5), and week and the interactions between treatment and parity, and treatment and week with a random effect included for cow. There were no significant differences between the Control and Progut Rumen treatments for the milk composition traits. There was a significant increase in milk yield for the Progut Rumen treatment in the entire dataset (P<0.01), > 24kg dataset (P<0.01) and the >30 kg dataset (P<0.05). There was a significant decrease in SCS for Progut Rumen compared to the Control treatment in the entire dataset (P<0.01), > 24kg dataset (P<0.05) and the >30 kg dataset (P<0.05). In conclusion supplementing dairy cow diets with Progut Rumen did not alter milk composition, however it increased milk yield and decreased SCS indicating possible beneficial effects on the dairy cows’ immune system.
Keywords: hydrolysed yeast, milk yield, somatic cell score