Zero-grazing dairy cows delivered a higher margin per hectare than both a silage-based diet and grazing in paddocks, according to a new study published by AgriSearch and released at the RUAS Winter Fair.Research conducted at AFBI Hillsborough found that the total cost of zero-grazed grass was £123/t of dry matter (DM), compared with £148/tDM for silage and £99/tDM for grazed grass.