EVALUATION OF STRESS BIOMARKERS IN TRANSPORTED GOATS UNDER VARIABLE CLIMATIC CONDITIONS

Abstract

This study is an analysis of how transport time and climatic conditions affect stress parameters in goats.  We transported 120 adult goats in four experimental conditions with three transport time (short 2 hours; long 8 hours) and three temperature-humidity index (THI) levels (low 70; high 80).  We considered physiological parameters, endocrine parameters, parameters of oxidative stress, and inflammatory markers at various points in time.  The findings indicated that goats transported prolonged in high THI displayed significantly higher rectal temperatures (40.8 o C ), respiratory rates (62 breaths/min) as well as heart rates ( 105 beats/min ) compared to the other groups.  Serum cortisol (48 ng/mL), metanephrine (260 pg/mL), and normetanephrine (210 pg/mL) were far higher in the long-high THI group postTravel. Their heart rate variability also decreased considerably.  Oxidative stress indicators revealed increased malondialdehyde (3.2 nmol/mL) with a reduced activity of superoxide dismutase and glutathione S-transferase.  Heat shock protein HSP70 (2.8 ng/mL) levels were considerably higher under combined stress conditions of heat and transport.  Two of the inflammatory markers that increased with the worsening of stress are interleukin-6 (30 pg / mL) and creatine kinase (225 U / L).  Multivariate analysis confirmed strong relationships between THI, transit time and total stress responses.  These results highlight the complexity of the physiological stress generated by transportation at high temperatures and support the importance of a thorough evaluation of the biomarkers to guide the management practices capable of supporting the welfare of goats during transport.