Heat tolerance in Brazilian sheep: physiological and blood parameters

Trop Anim Health Prod. 2009 Jan;41(1):95-101. doi: 10.1007/s11250-008-9162-1. Epub 2008 Apr 9.

Abstract

Thirty Santa Ines adult, non-lactating, non-pregnant ewes, ten with a brown coat, ten black coated and ten white coated, as well as ten Bergamasca and ten of mixed breed were used to evaluate the effect of climate on physiological and blood parameters in sheep. Two sample collections were taken (6 AM: and 2 PM: ) on six days. Sweating rate (SR), heart (HR) and breathing rates (BR), complete hemogram, rectal (RT) and skin temperatures (ST) were measured. Variance analyses were carried out using SAS(R). In general, there were significant differences between animals due to skin type, time and day of collection. White coated animals showed lower HR, BR and RT, with afternoon parameters higher than morning. Correlations between HR, BR, RT, SR and ST were medium and positive. Correlations between physiological and blood traits were in general negative and medium. Packed Cell Volume (PCV), total plasma proteins, red blood cell count and hemoglobin concentration had high positive correlations between each other. The first two autovectors explained 49% of variation between traits. White coated Santa Ines animals were shown to be better adapted to climatic conditions in Central Brazil and wool sheep more affected by heat.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptation, Physiological / physiology*
  • Animals
  • Blood Chemical Analysis / veterinary
  • Body Temperature Regulation / genetics
  • Body Temperature Regulation / physiology*
  • Brazil
  • Crosses, Genetic
  • Female
  • Heart Rate
  • Hematologic Tests / veterinary
  • Respiration
  • Sheep / blood
  • Sheep / genetics
  • Sheep / physiology*
  • Skin Pigmentation / genetics
  • Skin Pigmentation / physiology*
  • Stress, Physiological / genetics
  • Stress, Physiological / physiology*
  • Tropical Climate*
  • Wool