Respiratory heat loss in Morada Nova sheep in Brazilian semi-arid regions

This study aimed to evaluate the respiratory heat loss in sheep from the equations developed for this species and its relations with meteorological variables in semi-arid regions. The respiratory heat loss (sensible and latent) was estimated through the equations in the literature for four 12-month-old male Morada Nova sheep, kept in an installation with shading of ceramic tiles and a 3-meter-high ceiling. The following environmental variables were measured: air temperature (TA), wind speed (U), relative humidity (RH) and partial vapor pressure (PP{tA}). The physiological variables measured: rectal temperature (TR) and respiratory rate (RR). Statistical analysis was performed based on regression using PROC REG procedure in SAS. The latent respiratory heat loss showed a linear and positive correlation with ambient temperature. However, the respiratory convection showed a linear and negative correlation, but with incipient values. Therefore, the latent heat loss is more important than the sensible one in the respiratory system to maintain thermoregulation of sheep in a semi-arid region of Brazil.