Abstract 52

Lascano,C; Plazas,-C

CIAT, Cali, Colombia.

PasturasTropicales. 1990, 12: 1, 9-15; 9 ref.

In field trials on an Oxisol soil at Carimagua, native pasture dominated by Trachypogon vestitus, Paspalum pectinatum, Leptocoryphium lanatum and Andropogon bicornis and managed by 3 burns/year was stocked with 0.25 or 0.50 Zebu steers/ha. In 1988, native pasture was grazed alone or supplemented by 2000 m2 Andropogon gayanus cv. Carimagua-1 + Stylosanthes capitata cv. Capica/animal as an energy bank. In 1989 the effect of an energy bank was compared with a protein bank of 2000 m2 Pueraria phaseoloides/animal. Steer liveweight gains, quantity of forage on offer, grazing frequency and the diet selected by oesophagealfistulated animals was measured. In 1988, annual liveweight gains by animals with access to energy banks were 52 and 29% higher at low and high stocking rates, resp., the effect being more pronounced in the rainy period. The diet selected by those on the energy bank had 47% in vitro DM digestibility compared with 40% on savanna. In 1989 annual liveweight gains were 39% higher with the energy bank than the protein bank. CP levels in the diet were 15.5, 10 and 10.5% with the protein bank, energy bank and savanna, resp. It was concluded that the low digestibility of native savanna managed by burning in the Colombian Llanos Orientales limits animal production.