BRIEF COMMUNICATION: Effect of timing of maize silage supplementation on grazing behaviour of dairy cows during a short grazing session on a ryegrass-based herbage

摘要

The objective of this study was to evaluate the effect of timing of maize silage supplementation on grazing behaviour of dairy cows during a short grazing session on a ryegrass-based herbage. Thirty-six dairy Holstein-Friesian x Jersey dairy cows wereblocked in nine groups and randomly assigned to one of three treatments: herbage only (CTL), or supplemented with 3 kg DM/cow of maize silage at either nine (9BH) or two (2BH) hours before herbage allocation. Individuals' behaviour (grazing, ruminatingand idling) was visually assessed every five min during one grazing session. Herbage intake rate was estimated as herbage intake divided by grazing time. Cows in 2BH spent more time ruminating and had lower herbage dry matter intake rate than the cows inCTL and 9BH. Maize silage supplementation at two hours before herbage allocation, increased rumination time and reduced herbage intake rate. These results help in the design of feeding management and strategies to reduce herbage substitution rates.