Regression Analysis of Physiological Responses of Red Sokoto and West African Dwarf Goats to Heat Stress

Background and Objective: Livestock goes through diverse forms of stress, including psychological, chemical, nutritional, thermal and physical stress. Changes in rectal temperature, respiratory rate, heart rate and skin temperature are in part physiological responses to thermal stress. This study was conducted to identify the regression analysis of physiological responses of ancient/native breeds of goats (West African Dwarf and Red Sokoto) to heat stress in Nigeria. Materials and Methods: Physiological data (rectal temperature pulse rate and respiration rate) at various environmental conditions (ambient temperatures and humidity) were taken from 400 experimental animals (200 West African Dwarf breeds and 200 red Sokoto breeds of goats in Osun, Oyo and Kwara states, Nigeria. Temperature and humidity index (THI) were calculated at various environmental conditions prevailing during the study and consequent on this, an Analysis of Variance (ANOVA) was performed with respect to the different physiological indices that were measured. Results: Regression analysis between the parameters was also carried out, generating the coefficient of determination (R²) to indicate the efficiency of prediction. The results from the physiological parameter measurements and THI analysis revealed that the results for the physiological parameters were similar at breed level; heart beat rate, rectal temperature and respiration rates changed significantly with increasing THI values. The regression analysis showed that THI had a positive and significant (P<0.05) effect on heat beat rate R² (0.623), respiration rate R² (0.36) and rectal temperature R² (0.157) of Red Sokoto Breed. The THI also had positive and significant (P<0.05) in West African Dwarf goats for all physiological parameters. Heart beat rate R (0.544) respiration rate R² (0.359) and rectal temperature R² (0.187). Conclusion: These physiological responses make goats exist and linger in harsh and cacophonous environments.