Effect of Essential Oil Supplement on Milk Yield and Composition of Lactating Dairy Cows

Essential oils (EO), an important group of plant extracts, which are concentrated extracts of aromatic oily liquids from various plant materials obtained by steam distillation. Plant-derived EO is a useful means to improve efficiency of nutrient utilization in ruminants and reduce the impact of their production on the environment. In recent years, more research has been directed toward evaluating the potential of EO to improve performance in dairy cows but according to the results the effect of EO on milk production is not consistent. Therefore, the study evaluated the effects of supplementing a mixture of EO (oregano, thyme, citrus, cinnamon, ginger, curcuma, pepper and an organic carrier) in the diet of lactating Holstein Friesian dairy cows (n=46) in late lactation on the intake, milk yield and composition in a dairy farm experiment. The average DIM at the start of the experiment was 156 days. Experimental treatments consisted of a mixture of EO (2 g cow-1 day-1) inclusion in a total mixed ration. There was a 3-week long preliminary and a 7-week long experimental period in the trial. Milk production was recorded every day. Chemical analyses were made from the morning milked samples once a week. Supplementation of dairy cows with mixture of EO significantly (P<0.05) increased the dry matter intake (control: 26.9±1.49 kg DM day-1 vs. experimental: 27.3±0.95 kg DM day-1) but had no effect on milk production (control: 38.3±4.99 kg vs. experimental: 37.9±4.93 kg) and milk composition (fat, protein, lactose). Results show that an intake of 2 g cow-1 day-1 mixture of EO may increase the feed intake but does not influence milk yield and composition in late lactation.