Grape marc is the skins, seeds and stems remaining after grapes (Vitis vinifera) have been pressed to make wine. Some Australian dairy farmers feed grape marc to cows during late summer and during droughts. Recent research has shown that when grape marc was included in a diet typically fed to dairy cows in late summer, milk production was maintained and methane emissions were reduced by 20% (Moate et al. 2014).
During spring, Australian dairy pastures may be lacking in neutral detergent fibre (NDF). This research examined if inclusion of ensiled red (RGM) or white (WGM) grape marc in a diet composed principally of perennial ryegrass would influence milk production and decrease methane emissions of dairy cows during early lactation.We hypothesised that because both types of grape marc have similar concentrations of major components such as NDF, lignin and lipids, the effects on milk production and methane emissions
would be similar for both types of grape marc.