Williams et al., 2000. Asian-Aust. J. Anim. Sci., 13 (Suppl. July): 509-512

To examine the differences in grazing behaviour when lactating cows eat contrasting types of high quality pastures (Persian clover (Trifolium resupinatum L.) or perennial ryegrass (Lolium perenne L.)) offered at high or low allowances in spring, the behaviour of cows was recorded both manually by visual observation and automatically using sensors that recorded jaw movements. Cows grazing Persian clover at the high allowance grazed longer than cows at the low allowance (p<0.05). Cows grazing Persian clover ruminated less and spent more time not chewing throughout the day (p<0.05) than cows grazing perennial ryegrass. The times recorded by automatic recorders were similar to those recorded by visual observation. The grazing jaw movement rates of cows grazing both pasture types were similar and remained constant during grazing bouts throughout the day. Cows grazing ryegrass had a higher bite rate than cows grazing Persian clover (p<0.05). High quality grass and clover pastures can be eaten at similar, rapid rates but they are eaten in a different manner.