Grape pomace supplementation reduced methane emissions and improved milk quality in lactating dairy cows

Summary

Grape pomace (GP) is a byproduct of the viticulture industry and shows promise for feeding dairy cattle as well as reducing enteric methane (CH₄) emissions. This study investigates the potential of using fresh GP in dairy cow feeding and its effects on CH₄ emissions. Multiparous Holstein dairy cows (n = 24, 205 ± 39 DIM) were housed in freestall barns and provided rations consisting of alfalfa hay, wheat hay, almond hulls, cottonseed, and grain mix. After a 2-wk adaptation period, cows were randomly assigned to one of the 3 treatments: a control diet (CON), a diet with 10% grape pomace (10% GP), and a diet with 15% GP (15% GP) on a DM basis. Treatments were arranged in a 3 × 3 Latin square design, where cows received 3 treatments over 3 periods, each period lasting fo