Effect of summer heat stress on physiological and haemato-biochemical characters in Kanni ADU and Kodi ADU Goat breeds of Tamil Nadu

Twenty-four goats of Kanni Adu and Kodi Adu breeds were randomly allocated into four groups of six each viz., Gr-I (Kanni Adu, control), Gr-II (Kanni Adu, treatment), Gr-III (Kodi Adu, control) and Gr-IV (Kodi Adu, treatment). Treatment groups were exposed to summer heat stress from 08.00 am to 02.00 pm in open environment from last week of April to mid of June, 2020 with mean temperature humidity index (THI) of 84. Animals in both the breeds exposed to the summer stress (Gr-II and Gr-IV) showed significant (P<0.05) increase in respiratory rate, RR (33.83±3.83 and 26.67±1.43/min) heart rate, HR (111.33±5.38 and 113.67±6.16/min), rectal temperature, RT (39.28±0.11 and 39.50±0.14°C) skin temperature, ST (38.33±0.55 and 40.03±0.19°C) than control group (Gr-I and Gr-III) RR 24.00±2.19 and 26.00±2.53/min, HR 85.33±2.29 and 91.33±2.86 /min, RT 37.63±0.08 and 38.97±0.15°C and ST 36.75±0.06 and 37.12±0.22°C respectively. However no alteration was observed in haemoglobin, packed cell volume, glucose, total protein and cholesterol. It ranged from 6.77 to 7.73 g%, 25.50 to 35.83%, 49.32 to 55.50 mg/dl, 5.17 to 5.32 g/dl and 46.12 to 53.40 mg/dl, respectively in animals of both the breeds under control and treatment groups. In conclusion, both Kanni Adu and Kodi Adu goats maintained their hydration status and metabolic profile and increased physiological responses to ameliorate the heat stress, indicating better adaptation characteristics of goats to hot tropical climate.