Grazing time and pattern of grazing of Friesian cows on a tropical grass-legume pasture

Abstract

Grazing time and pattern of grazing were recorded for 40 milking Friesian cows grazing a Panicum maximum var. trichoglume-Glycine wightii cv. Tinaroo pasture at stocking rates of 1.3, 1.6, 1.9 and 2.5 cows ha-1. These measurements were taken during summer and winter in a tropical upland environment. In a second experiment the effect on grazing time of feeding 4.5 kg crushed maize cow-1 day-1 was assessed using 16 milking Friesian heifers grazing P. maximum var. trichoglume-G. wightii cv. Tinaroo pasture at a stocking rate of 1.3 cows ha-1. Daily grazing time was similar at approximately 600 minutes in summer and winter, though in summer cows reduced day grazing and increased night grazing time. Reduction in day grazing was closely associated with daily maximum temperature. Grazing patterns showed a lower percentage of cows grazed during the middle of the day in summer than in winter and a higher percentage of cows grazed throughout summer nights than during winter nights. There was some evidence of a positive relationship between grazing time and milk yield. No significant relationship between pasture yield and grazing time was established. Feeding 4.5 kg maize cow-1 day-1 reduced grazing time per day by approximately 15 per cent.