Adaptive profile of Saanen goats in tropical conditions

ABSTRACT

The objective was to characterize the adaptive profile and thermoregulatory responses of Saanen goats raised under tropical conditions. Twenty dairy goats were used. Its rectal temperature (RT, °C), respiratory rate (RR, breaths min⁻¹), and heart rate (HR, bpm) were collected biweekly for two consecutive years. Individual blood samples were collected for determination of thyroxine (T₄; μg dL⁻¹). All physiological responses were higher in the afternoon, except for RR which was higher in the morning. The RT and RR were higher in the rainy season, and HR and T₄ levels had no effect between periods of the year. The RT, HR, RR and T₄, in this order of importance, are the most important variables to characterize the adaptive profile of the animals. The thermoregulatory responses during the morning and afternoon shifts were similar, whereas between periods of the year the animals used different mechanisms to maintain homeostasis. Saanen goats mainly use the latent thermoregulation mechanisms in the rainy season as a form of endogenous heat dissipation and the sensitive mechanisms in the dry season. The RT is a physiological variable that presents discriminatory power for evaluation of adaptive aspects in Saanen goats in tropical conditions.

KEYWORDS:

• Adaptation
• dairy goats
• multivariate analysis
• semi-arid
• thermolysis

Acknowledgments

To the Fundação Cearense de Meteorologia e Recursos Hídricos (FUNCEME) for the concession of climatic data. To the Clinical Pathology Laboratory of Embrapa Goats and Sheep (EMBRAPA Goats and Sheep), in particular, to Professor Dr. Raymundo Rizaldo Pinheiro, for the viability of the hormonal analyzes. To the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES), for the financial support in the form of scholarship during the master‘s degree course.

Disclosure statement

No potential conflict of interest was reported by the authors.