ENERGY REQUIREMENTS OF INDIGENOUS AND EXOTIC LACTATING COWS IN A HUMID, TROPICAL ENVIRONMENT

Résumé

Owing to paucity of information on the energy requirements of lactating cows in a humid tropical environment, a study using twelve lactating cows and Six steers was conducted at Ibadan, Nigeria. Animals weighing between 355 and 445kg were used in metabolism studies with four cows and two steers from each of the White Fulani (WF), German Brown (GB) and Friesian (F) breeds. Metabolizable energy (ME) required for maintenance ranged from 0.37 for the Friesiun, 0.41 for the German Brown to 0.44 MJ/day/W^0.734kg for the White Fulani animals. Since the regressions were parallel and coincident, pooled figures of 0.41MJ ME/day/W^0.734kg or 0.31MJ net energy ME/day/wk^0.734g for all breeds in a tropical environment could be used. Efficiency of utilization of metabolizable energy for milk synthesis was about 31%. while a large variation was obtained for efficiency of utilization of the diets fed forage (18%), low concentrate (32%, and high concentrate (44%). Lactating cows required lower maintenance but higher productive metabolizable energy than those in the temperate regions.