Effects of live yeast on the rumen fermentation parameters and milk performance of Simmental dairy cows during the hot season

Abstract

The effects of dietary supplementation with live yeast culture (LY) on the milk performance and rumen fermentationparameters of Simmental cows in the middle of lactation were examined under hot season conditions in 2019. The 28 cows, which weredivided into two experimental groups of 14, were fed a controlled diet, with or without the addition of 5 g of LY per cow daily. The meandry matter intake (DMI) and yield of milk in the LY group were greater by 0.25 kg/day and 0.42 kg/day, respectively, than for the controlgroup. The yields of milk components and 4% fat corrected milk were also significantly greater in the LY group than in the controlgroup, but LY supplementation did not significantly alter milk composition percentages. The acetate concentration in the rumen tendedto be higher in cows fed LY but the ruminal pH, NH3-N, propionate and butyrate levels, and acetate/propionate ratio were similar inthe two groups. It can be concluded that LY supplementation of the diet of Simmental dairy cows during the hot season improved milkproduction and ruminal fermentation performance to a limited degree.