Grape marc is the skins, seeds and stems remaining after grapes (Vitis vinifera) have been pressed to make
wine and is increasingly being used as a source of nutrients (fibre and oil) for dairy cows. Grape marc has been
shown to be a methane mitigant when consumed by dairy cows on a conserved forage diet in late summer.
Thirty-two Holstein-Friesian cows were fed individually for 28 days to determine if red and/or white grape
marc were a suitable replacement for fresh pasture, and would reduce methane when cows were fed fresh
pasture. Cows on all treatments had similar dry matter intakes and the nutritional characteristics of the red and
white grape marcs were similar. Milk yield and methane yield (g CH4
/kg DMI) of cows fed grape marc were
unaffected by type of grape marc and were 14% lower than for those fed pasture only. Feeding grape marc
in place of spring pasture reduces methane emissions from dairy cows but this benefit is overshadowed by a
reduction in milk production