EFECTO DE TRES EDADES AL DESTETE SOBRE EL CRECIMIENTO Y CONSUMO DE CONCENTRADO EN TERNEROS DE LECHERÍA.

The effect of three weaning ages (12, 9 and 6 weeks) on the gain in weight and take of concentrate in calves specialized dairies of the high lands of Chiriqui was evaluated. Eighteen pure Holstein calves weight of 40.0 kg at birth were alloted at randon in each treatments using divided parcel model on time in which the main parcels were the principal parcels and the periods the subparcels. The calves were evaluated for six months after birth. The crude protein of the concentrates at initation and during growth was 21.4 and 15.5%, respectively. Both concentrates were given at libitum during the trials. The taking of concentrate was registered two times a week until the age of four month. The calves were weighted weekly and were instaled on individual cages until the age of four months and collective cages until the age six months. It was administered 4.0 liters of milk in two daily weaning. The calves also were grazing African star (Cynodon Plectostachyus) for six hours a day until the age of four months and daily until the age of six month. The total mean gain weight per calf until six months were 80.9, 85.8 and 99.6 kg for 12, 9 and 6 weeks, respectively (P>0.29). The mean taking of concentrate until the fourth month were 0.931, 1.153 and 1.560 kg/animal/day for 12, 9 and 6 weeks, respectively (P<0.001). During the week following the weaning, the calves increased the taking of concentrate in 56.9, 108.7 and 234.5% for 12, 9 and 6 weeks as a mechanism of compensation for the lack of milk diet. The weaning at 9 and 6 weeks reduces the feeding costs in 22.5 and 30.5%, respectively, in relation to weaning at 12 weeks. It is feasible, in practical circumstances to the producer, to reduce the age of weaning to six weeks as long as adecuate conditions of feeding, sanitation and hadling are maintained.