Impact of short term exposure to different environmental temperature on the blood biochemical and endocrine responses of Malpura ewes under semi-arid tropical environment

Abstract

The study was conducted to establish the impact of short term exposure to different environmental temperature on adaptive capability of Malpura ewes in terms of changes in blood biochemical and endocrine responses. The experiment was conducted for 21 days in 28 Malpura ewes, which were randomly divided into 4 groups of 7 animals each (G1- control, G 2–23°C, G 3–40°C, G 4–42°C). The ewes were exposed to different temperature for a week and blood collection was carried out on day 0, day 1, day 4 and day 7 for each group. The effect of different temperature exposure was studied on blood biochemical and endocrine parameters. Haemoglobin (Hb), packed cell volume (PCV), plasma glucose, total cholesterol, total protein and albumin also showed highly significant variation for the different temperature exposure. All endocrine parameters showed highly significant variation for the treatment. The highest cortisol concentration was recorded in group 4 (34.73 nmol/L) while the lowest being in group 2 (8.35 nmol/L). Plasma thyroid hormones showed reverse trend as that of cortisol in that the highest concentration was recorded in group 2 while the lowest being in group 4. The data indicated that Malpura ewes have the capability to alter their adaptive capability on exposure to different environmental temperatures. Further, the study proved that heat stress effect was established both at 40°C and 42°C in these ewes but the effect was very severe on exposure to 42°C. This shows that each degree increase in upper critical temperature might be very detrimental to the survival of these animals.