Tendências metodológicas para avaliação da adaptabilidade ao ambiente tropical

Abstract

The adaptation of animals to breeding environment is essential to the success of any livestock enterprise. In Brazil, some decades ago, several breeds were imported, originated from temperate climates, from various species of farm animals whose progeny were evaluated and selected taking into account only the productive aspects. In the last ten years it was found that both creators and the academic community awoke to the promotion of adaptive aspects when selecting animals to be created in many different biomes. There is thus, the recovery of native breeds of zebu cattle and small ruminants for meat and milk productions. However, evaluate and select animals for adaptive traits require the standardization of parameters and methodologies for the collection of reliable data. Whereas homeostasis represents the equilibrium condition in a biological system and that animals adapted to the environment exhibit clear signs of homeostasis, this study sought to address a methodology composed of a multifactorial matrix to evaluate the adaptation, which are considered the thermoregulatory reactions As a way to maintain homeothermy indicated by rectal and surface temperatures and activation of evaporative heat loss, represented by the respiratory rate and sweating rate. For evaluation of homeostasis is recommended the association of endocrine reactions, such as circulating levels of thyroid hormones and cortisol, to the biochemical parameters within the normal range. All of these factors in balance allow the animals to express satisfactorily the reproductive and productive roles.