Effet de l’huile de tournesol sur l’émission de méthane entérique chez la vache laitière

Abstract

The objective of this study is to evaluate the effect of sunflower oil on enteric methane emissions in dairy cows. Fermentation in the digestive tract of ruminants contributes about 18% of world production of this potent greenhouse gas. The study focused on measuring methane production before and after the addition of sunflower oil to the ration of five Holstein cows. The basal ration was composed of 4 kg of feed concentrate and 3 kg of alfalfa hay. After two weeks of adaptation to diet, methane production was measured. Then, 200 ml of sunflower oil was added to the same basal ration and a second methane measurement was made after two weeks of adaptation. To assess the influence of the circadian cycle on methane production, five measurements of methane emissions were conducted over a period of 24 hours on the same animals. The daily amount of methane produced by cows was estimated to average 185 liters/day. Methane production by cows has decreased from 7.5 l/h to 4.1 l/h during an interval of 24 hours between meals, which represents a decrease of 45.2 %, and then increased again after the second meal to reach 7.1 l/h; it was not affected by the circadian cycle but by feeding time. Methane was predominantly emitted by eructation (89 %) and the remainder is removed with the respiratory gas (11%). The effect of sunflower oil on methane emission was small but significant (p <5%) with a reduction by 8.1 %. The affordable cost of this additive makes it a promising component to reduce emissions of enteric methane in the atmosphere.