LIVEWEIGHT CHANGE OF CENTROAMERICAN MILKING CRIOLLO HEIFERS GRAZING STARGRASS AND KUDZU IN THE TROPICS

Abstract

Thirty-two Criollo Lechero Centroamericano (50 to 100 % purebred) heifers (150.6 ± 2.6 kg initial liveweight) grazed unfertilized Stargrass (Cynodon nlemfuensis) pastures at Turrialba, Costa Rica (humid tropics), under a rotational system with 4.1 head ha-1 (six pastures, 7.8 ha each, during 125 days). Heifers were randomly assigned to four treatments (eight per group): 0, 1.5, 3 and 5 h d-1 in a Kudzu (Pueraria phaseoloides) pasture. Access to Kudzu did not increase (p> 0.05) heifers average daily gain (361, 385, 358 and 407 g d-1 for 0, 1.5, 3 and 5 hours of daily grazing on Kudzu, respectively). Ingesta samples from five additional heifers, with esophageal fistula, showed that average crude protein content of Stargrass throughout the study was 13.2 % for stargrass and 20 % for Kudzu. No differences (p>0.05) in crude protein content were found for Kudzu grazed by heifers at the beginning (21.4 %), 2.5 h (19.8 %) and 5 h (19.5 %) of Kudzu grazing. Microhistological analysis of feces indicated that Kudzu in the diet varied from 27.9 to 42.6 %; the highest proportion (p