BOTANICAL COMPOSITION AND DIET QUALITY OF GOATS GRAZING NATURAL AND GRASS RESEEDED SHRUBLANDS

摘要

Botanical and chemical compositions and diet consumption of goats grazing on xerophyte shrubland communities with and without grass reseeding were estimated during March, July and November in three consecutive years. Botanical composition of the diet was determined by microhistology, digestibility in vitro and consumption of nutrients. Forage samples were obtained from esophageal fistulated animals and feces collection from intact animals. Of the species identified in the diet, 93% were shrubs and herbaceous plants, these being more abundant in esophageal samples of animals on no-reseeded sites. Correlation upon time of these two groups of plants was inverse (P < 0.05) for both types of shrublands, just as the correlation between shrubs and gramineous plants. It was observed that as the dry season advanced, the herbaceous plants (after being the predominant species of the esophageal samples) and gramineous plants diminished in the diet and the only relevant species were shrub-like plants. Functional relationships to predict the chemical composition of the diet from its botanical components or from the characteristics of feces, as well as to predict consumption from components of the feces are discussed. The botanical composition changed between year and seasons within years. Nutritious characteristics of the ingesta, with exception of lignin concentration, did not show real differences (P > 0.05) between shrublands with and without reseeding.