RESTRICCIÓN DEL AMAMANTAMIENTO EN VACAS DEL SISTEMA CRÍA LIBRE

In order to increase the pregnancy rate which it was found diminished by the incidence of a long anoestrus postpartum in lactating cows in the farm Andalucía, the technology or ?restriction of the suckling period to 30 minutes each day? was applied. 38 cows that had more than one month of post-partum period, and that they had not been observed in heat and that to the rectal palpation were found empty. Two homogeneous groups of cows as for numbers of parturitions and post-partum days were conformed, one that was committed to restriction of the feeding-breast and another that served of group control. The raises of the group submitted to restriction of the feeding-breast suckled during 30 minutes each day, the remainder of the time they were maintained grazing separated of its mothers, and one an alimentary supplement was offered. This management was maintained to when the cow showed heat. The raises of the group control remained with their mother the 24 hours of the day. It was carried out rectal palpation to the start and each 3 months. During the time that technology was applied they registered the following variables: percentage of pregnancy, open days, weight to the calf to start the restriction and to the weaning, cost of the technology. With the application of the restriction of the feeding-breast to 30 minutes each day, the percentage of pregnancy in 32% was enlarged and the open days they were reduced and calving days to the first heat in 61 and 41 days respectively. The weights of the calves to the weaning was smaller in 20kg for the calves submitted to restriction, due possibly to the high presence of weeds in the pastures (>40%), produced by problems of security in the zone, which it impeded the visit of supervision and control of the cattle raising to their farm. With the application of the technology an increase in the net income was obtained (in colombian pesos of the year 2000) of $12'352. 500. The significant increase in percentage of pregnancy, compensates economically the smaller one to the weaning, doing viable and attractive the application of the technology in these systems of production.