Role of housing microclimate in shaping physiological, hormonal, and productive traits in goats under tropical stress conditions.

This study investigated the effects of housing systems on physiological, reproductive, hematological, biochemical, hormonal, oxidative stress and productive traits in Andamani goats under humid tropical ecosystem in Andaman and Nicobar Islands, India. Thirty-two goats (16 males and 16 females) were housed from birth to 12 months in two contrasting environments: a newly constructed and well-ventilated shed (new shed) and an old and poorly ventilated shed (old shed). Ambient and shed microclimate data such as temperature-humidity index (THI) were monitored in both the sheds throughout the year. The internal THI was significantly lower in the new shed (76.91 ± 0.57) as compared to the old shed (80.39 ± 0.47); although both sheds had similar external THI. The goats housed in the new shed had exhibited significantly (p < 0.05) improved body weight, growth rate, reproductive parameters, scrotal circumference, testicular weight and testosterone concentrations. The hematological parameters such as red blood cell count (RBC), hemoglobin (Hb), packed cell volume (PCV) and mean corpuscular volume (MCV) were higher in the new shed whereas the erythrocytic sedimentation rate (ESR) and white blood cell count (WBC) were increased in the old shed which indicated that the animals housed in old shed were suffered with physiological stress. The goats from the old shed expressed higher rectal temperature, pulse rate and respiratory rate along with elevated cortisol and prolactin concentrations and reduced concentration of thyroid hormones. The markers of oxidative stress were higher and antioxidant efficiency was lower in the old shed group. The biochemical parameters indicated better metabolic status in goats from the new shed with higher glucose, protein, and lipid profiles, and lower liver and kidney stress markers. The milk yield and its quality composition were superior in the goats of the new shed. The correlation analysis revealed the strong negative relationships between both the external and internal THI and productive, reproductive, hematological, hormonal and milk quality parameters particularly in the old shed goats. These findings demonstrated that the improved house designs had significantly mitigated the heat stress and enhanced the goat health and productivity in the humid tropical island eco-system.