EFFECTS OF BREED AND SEX ON THE THERMO-PHYSIOLOGY, HAEMATOLOGY, SERUM BIOCHEMISTRY AND THYROID HORMONE PROFILE OF NIGERIAN GOATS

This study was embarked upon to evaluate the breed and sex effects on the thermo-physiology and blood parameters; predict heat stress index and appropriately classify West African Dwarf (WAD) and Red Sokoto (RS) goats that are predominantly found in Nasarawa State, Nigeria. Twenty four (n=24) healthy, non pregnant goats of both sexes of equal numbers of WAD and RS were used. The experiment was arranged in a 2 x 2 factorial in a completely randomized design. General Linear Model (GLM) procedure was employed to test the fixed effects of breed and sex including breed * sex interaction on the parameters. Artificial Neural Network (ANN) algorithm was used to predict heat stress index while the standardized discriminant function was used to screen for the most discriminating variables to separate WAD from RS goats.WAD goats had higher rectal temperature (38.93±0.10versus 38.59±0.10) and pulse rate (54.78±0.24 versus 53.67±0.24) compared to their RS counterparts. However, there was no significant difference in heat stress index between WAD and RS goats. Based on thermo-physiological parameters, male goats appeared to be more stressed. There was no significant Breed * Sex interaction effect on thermo-physiological traits. The results of haematological and serum biochemical and hormonal indices of goats also indicated that WAD goats appeared to be more stressed. The female goats appeared to be more stressed than their male counterparts as a result of some high hormonal indices. There was no significantly (P>0.05) different on Breed * Sex interaction effect on haematological indices. However, there was a significantly (P<0.05) on interaction effect on thyroid stimulating hormone (TSH). While male and female WAD goats were similar, female RS goats had higher value of TSH (1.20±0.21) than their male counterparts (0.57±0.21).The ANN algorithm revealed that respiratory rate, cortisol, pulse rate and WBC which had more influence on heat stress prediction in goats compared to breed, sex and other haematological, serum biochemical and hormonal parameters. Haemoglobin, white blood cells, rectal temperature and pulse rate were sufficient to correctly assign WAD and RS goats to their appropriate breed (100% and 83.3% for correct original grouped cases and cross-validated assignment). The present information may aid breed characterization and conservation of WAD and RS goats in Nasarawa State, Nigeria.