An Essential Oil Blend Decreases Methane Emissions and Increases Milk Yield in Dairy Cows

Abstract

This study was conducted to investigate the effect of a commercial essential oil (EO) additive on milk production and methane (CH 4) emissions from dairy cows. Early lactation Holstein-Friesian dairy cows were fed grass, whole crop wheat and corn silage total mixed ration. Cows were allocated to one of two experimental treatments: Control (no additive, CON) or 1 g/head/day of EO. Cows were housed in a free stall barn, split into two pens for the duration of the experiment. Two gas data loggers units used to measure CH 4 emissions were provided per pen for the duration of the 22 week-long study. Milk yield was determined daily, and milk components were analyzed every two weeks. CH 4 was recorded continuously, and daily values were tabulated. Body weight and body condition score were determined at the start and biweekly. Results were analyzed as a randomized complete block trial. In total, 149 cows participated in the study (76 CON, 73 EO). Milk yields were greater (P < 0.05) for the test treatment (28.3 CON, 31.2 EO) with no change in milk component concentrations. Milk component concentrations were unaffected (P > 0.05) by treatment. Yields of fat, protein, lactose, and solids were higher for EO fed cows (P < 0.05). CH 4 output was reduced with the EO compared to the CON treatment (411 g/day vs 438 g/day; 13.8 g/L of milk vs 17.2 g/L of milk, P < 0.05) over the duration of the trial. There were no effects of treatment on reproductive performance or the occurrence of mastitis. Feeding EO to dairy cows reduced CH 4 emissions whilst also increasing performance.