Physiological reactions of three breeds of goats to cold,heat and high altitude

A total of 36 goats of the breeds Gemsfarbige Gebirgsziege (G), Saanen (S) and Toggenburger (T) were exposed for periods of 4 hours to the following climatic conditions: normal (20°C, 50% RH); cold (?5°C); heat (40°C, 30% RH) and high altitude (4000 m, 20°C, 50% RH).In the cold the animals were just able to maintain normal core temperature. Skin temperatures on the flank decreased by 3–5°C, those on the ear and the shank by 20–21°C. Respiratory rate and blood-pH decreased. The elevation in heart rate (18 beats/min) and cold shivering were indicative of a rise in heat production.In the heat, rectal temperature increased but attained a plateau at 40.7°C. Respiratory rate rose from 26 to 261 breaths/min, producing a slight respiratory alcolosis with a rise in blood-pH of 0.036 units. Heart rate augmented by 15 beats/min.At high altitude rectal temperature declined by 0.2°C, which was attributed to the quiet behaviour of the goats. There were increases in haemoglobin (+0.83 g/100 ml), haematocrit (+2.5 vol.%), erythrocyte number (+0.78 mill./mm³) and specific gravity of the blood (+0.002). The increases were considered to reflect discharge of blood from reservoirs, since they occurred within 4 hours. A rise in pH, unaccompanied by a rise in respiratory rate, pointed to an increase in tidal volume.There were suggestions of breed differences. The T-breed appeared to be relatively cold tolerant owing to the high thermal insulation of their hair coat, and also relatively heat tolerant, possibly due to their low heat production, as evidenced indirectly by their low normal heart rate (87 compared with 95 beats/min in the other two breeds).