author(s)
Mayuri Chetia, Satya Sarma, Rita Nath and Shantanu Tamuly

abstract
One of the main reasons for oxidative stress in animals during summer season is heat stress. The present experiment was aimed to study the effect of summer and winter season on the stress related antioxidant enzymatic profile of zebu cattle in Assam. The different enzyme activities such as SOD (Superoxide Dismutase), GSH-Px (Glutathione Peroxidase) and CAT (Catalase) were analysed by different standard methods. It was observed that all the erythrocytic antioxidant enzyme activities were increased in summer compared to winter season and the difference was highly significant (P<0.01). The increase in antioxidant enzyme activities might be attributed to the adaptation and the acclimatization of the animals towards the thermal stress of the summer season.