Effect of timing of pasture and silage allocation on behaviour, fed intake, and milk production of grazing dairy cows during Autumn

Abstract

We evaluated the effects of timing of pasture and grass silage allocation on the behaviour and milk production of dairy cows grazing perennial during autumn. Over 57 days, 45 multiparous Holstein-Friesian cows (519 kg live-weight, 24.5 kg milk/d and 57 days in milk) were allocated to three treatment groups: 75% of the herbage and 25% of the silage allowance were allocated in the morning; 50% of the herbage and silage allowance were allocated in the morning; and 25% of the herbage and 75% of the silage allowance were allocated in the morning. All treatments received the complement of herbage and silage in the afternoon. All groups were strip-grazed with an herbage allowance of 21 kg DM/cow/d, and supplemented with 3 and 3.5kg DM/cow/d of silage and concentrate, respectively. Milk production (kg/d) was recorded at each milking (07:00 and 14:00 h), and daily dry matter intake was estimated using Cr2O3. Grazing, rumination and idling times were recorded for each cow over 24h, twice. Treatments did not affect any of the measured variables (P>0.05). Milk production averaged 22 kg/d, while total and herbage intake averaged 14.2 and 7.7 kg DM/d per cow. Averages of grazing, ruminating and idling times were 343, 344 and 683 min/d, respectively. These results suggest that, under the conditions of the present study (low herbage mass and intake, and high level of supplementation), combinations of timing of pasture and silage allocation may not alter feed intake, grazing behaviour, and thereby milk production.