Eighteen lactating Kankrej cows were subjected to three housing systems viz., RCC shed (T1), Thatched roof (T2) and Tree shelter (T3). Serum concentration of T3 (Tri-iodothyronine), T4 (Thyroxin) and Cortisol hormones was estimated once in a season for one year. The overall average serum concentration (ng/ml) of Tri-iodo thyronine (T3) recorded under T1, T2 and T3 was 0.96 ±0.01, 0.89 ±0.02 and 0.90 ±0.02 respectively. The difference due to treatments, seasons and their interaction was non-significant. The overall average serum concentration (ng/ml) of Thyroxin (T4) recorded under T1, T2 and T3 was 25.17 ±0.9, 26.41 ±1.0 and 26.39 ±0.8, respectively. It was significantly (P < 0.05) higher in winter (37.30 ±1.0) as compared to monsoon (27.03 ±1.0) and summer (13.65 ±0.70), while difference due to treatments was non- ignificant. The average serum concentration (ng/ml) of Cortisol recorded under T1, T2 and T3 was 11.41 ±0.5, 12.57 ±0.5 and 12.11 ±0.6 respectively. The difference due to treatment was non-significant.  

Keywords: Hormone; Cattle; Stress.