The effect of opening farm cover on early lactation milk and milk solids production

Grass availability in spring is highly variable. Including grazed grass in the diet of early lactation dairy cowscan result in improved animal performance. The objective of this experiment was to determine if a highopening farm cover (OFC) can impact on early lactation milk production in a spring calving system. Inspring 2017 (6 February – 25 April), 45 cows were randomly assigned to one of three (n = 15) OFC; High(H) (974 kg DM ha-1), Medium (M) (863 kg DM ha-1) and Low (L) (624 kg DM ha-1). All cows wereallocated an equal daily grazing area. Post-grazing sward height and daily herbage allowance (DHA) weremeasured daily and pre-grazing herbage mass (> 3.5 cm) twice weekly. Milk yield was recorded daily andcomposition once weekly. There was a significant effect of treatment on daily milk yield (P 0.05) on the H treatment than the L treatment,with the M treatment intermediate. Higher OFC increases grass availability on the farm which increasesDHA, resulting in increased milk production performance