Composição botânica da dieta e índice de seletividade de pequenos ruminantes em pastejo no semiárido brasileiro

Abstract

In arid regions, small ruminants breeding has great socioeconomic importance, being the native vegetation the main forage resource. Knowledge about the botanical composition of the animals’ diet allows the proper management of the vegetation. This study aimed to determine the botanical composition and selectivity of sheep and goats diets grazing in two states of the Brazilian Semi-arid, at different times of the year. The studies were conducted in Sertânia – PE and Independência – CE. A completely randomized with five replications and a factorial arrangement 2x2x4 were used, being two localities (Independência and Sertânia), two animal species (sheep and goats) and four climate periods (rainy, dry-rainy transition, dry and rainy-dry transition). For the variable proportion of monocotyledons in the diet, it was verified an locality x animal specie x period interaction. It was observed a bigger proportion of monocotyledons in the sheep diet in comparison to goats in all periods of the year. It was observed effect of the animal species and location x period interaction for the proportion of dicotyledons in the diet. The proportion of herbaceous dicotyledons in the diet of the animals was similar to both localities, except in the period of rainy-dry transition. It was verified that the animal specie x period interaction for the variable proportion of woody in the diet. The proportion of the woody was greater in the goats diet than sheep. The principal component analysis revealed greater consumption of leaves, fruit and seeds at Independência. It was observed greater proportion of leaves in the goats diet, and participation of stem almost null in the diet of these animals. Sheep showed selectivity index for herbaceous monocotyledons. At the dry period, the difference between wood preference for goats and sheep tends to decrease. The diet selected by the animals was influenced by the studied factors. Sheep tend to select more monocotyledons and less woody species than goats during the rainy period. Goats have show greater dietary plasticity according to local climate changes and the time of the year.