Effects of live yeast and essential oil supplementations to dairy cattle diets on performance and milk composition

This study aimed to determine the effects of live yeast (LY) and essential oil (EO) on dairy cattle diets on performance and milk composition traits. A total of 120 multiparous (in 2nd and 3rd lactations) Holstein dairy cows were used and 30 animals were allocated to each treatment group. Treatment groups were as follows: 1) control, (C, without any supplementation), 2) essential oil mixture addition (EO, 10 g/day/cattle) 3) live yeast, (LY, Saccharomyces cerevisiae, 10 g/day/cattle, 4×10 9 CFU/g) 4) EO+LY (10 g/day/cattle +10 g/day/cattle). Experiments were performed for 16 weeks. Body weight, milk yield, and feed conversion ratio were not influenced by the treatments. Milk fat increased with EO supplementation to the diet. Milk protein decreased in the LY+EO group. Somatic cell counts (SCC) decreased significantly with EO supplementation. Milk lactose, casein, and density were not significantly influenced by the treatments. Milk urea concentration increased in the LY group. Milk-free fatty acids significantly increased in the EO group. Milk citric acid increased in the LY group. The control (C) group had greater pentadecanoic acid (C15: 0) content than the other groups. The myristic acid ratio (C14: 0) of the C and EO groups was greater than the myris-tic acid ratio of the LY and LY+EO groups. Based on present findings, EO mixture supplementation to dairy cattle diets had positive effects on milk fat content and SCC. KEY WORDS Milk fatty acids, somatic cell count, milk urea, natural feed additives.