Zanine et al., 2007. Arq. Bras. Med. Vet. Zootec., 59 (1): 175-181

The grazing behaviour of lactating cows in pastures of Brachiaria brizantha [Urochloa brizantha] and B. decumbens [U. decumbens] in a system of continuous stocking with variable stocking rates was evaluated. A completely randomized experimental design with 2 treatments (pastures) and 5 replicates was used. The experimental period lasted for 30 days, 20 for adaptation of the animals and 10 for 3 experimental evaluations of 24 h each at 5-day intervals. The grazing time of cows on the B. brizantha pasture (10.82 h) was lower than on the B. decumbens (12.86 h). The inverse behaviour was observed for rumination time (7.95 and 6.45 h) for cows on the pastures of B. brizantha and B. decumbens, respectively. The amount of bite per minute was lower for cows on the B. decumbens (37.30 h) than on the B. brizantha (42.12 h). There was an adequacy among grazing time, rumination time and rate of bites. As a consequence, no difference between pastures was observed for total of bites and time of idling.