Metabolic and productive response and grazing behaviour of lactating dairy cows supplemented with high moisture maize or cracked wheat grazing at two herbage allowance in spring

The aim was to determine the effect of the HA and supplement type (ST) on dry matter intake, milk production and composition, grazing behaviour, rumen function and blood metabolites of grazing dairy cows in the spring season. Experiment I: 64 Holstein Friesian dairy cows were distributed in a factorial design that tested two levels of daily HA (20 and 30 kg DM/cow.day) and two ST (high moisture maize [HMM] and cracked wheat [CW]) distributed in two daily rations (3.5 kg DM/cow/day). Experiment II: four mid-lactation rumen cannulated cows, supplemented with either HMM or CW and managed with the two HA, were distributed in a Latin Square design of 4 x 4, for four 14-d periods to assess ruminal fermentation parameters.