Selection pattern of Holstein-Zebu cows grazing stoloniferous and tufted type tropical grasses in a cafeteria type trial

Seven stoloniferous and 7 tufted grasses are being evaluated in a long­term trial on an acid ultisol in Trinidad in duplicate 3x3 m plots. The grasses were cut at five weekly intervals and nitrogen at 40 kg/ha applied after every harvest. A basal dressing of 125 kg P20��, and 100 kg '½O and a trace element mix was applied twice annually. After culling in May 4 milking cows were allowed to graze the area. There was no significant difference in dry matter yield between the stoloniferous and tufted grasses, but there were significant differences within each type of grass in dry matter yield, total leaf, percentage leaf and leaf bulk density, Grazing animals spent most of the time on the stoloniferous grasses. Their pattern of selection was not based on forages with highest yield, highest percentage leaf nor highest leaf bulk density, confirming that selection is based on a number of inter related factors.