AGRICULTURAL RESEARCH COMMUNICATION CENTRE www.arccjournals.com/www.ijaronline.in *Corresponding author’s e-mail & address: nekibahmeds@gmail.com Indian J. Anim. Res., 52 (4) 2018 : 513-517 Print ISSN:0367-6722 / Online ISSN:0976-0555 Effect of zinc supplementation on hormonal and lipid peroxidation status of peri-parturient Karan Fries cows during heat stress condition Brijesh Patel, Nishant Kumar * , Varsha Jain, Nitin Raheja, Satendra Kumar Yadav, Narender Kumar, S.S. Lathwal and S.V. Singh Livestock Research Centre, ICAR-National Dairy Research Institute, Karnal-132 001, Haryana, India. Received: 13-12-2016 Accepted: 25-01-2017 DOI: 10.18805/ijar.v0iOF.9139 ABSTRACT Present study was carried out to evaluate the effect of Zinc (Zn) supplementation on hormonal and lipid peroxidation status of peri-parturient KF (Karan Fries) cows during heat stress. Cows were grouped as C (6), T1 (6) and T2 (6). C was fed basal diet alone; however T1 and T2 were fed with 80 ppm and 120 ppm Zn, respectively along with basal diet from 45 days pre- partum to 45 days postpartum. It was found that Zn level was significantly (P<0.05) higher in supplemented group than control. Plasma cortisol was significantly (P<0.05) reduced in T2 compared to C and T1 at calving. T 3 and T 4 concentration decreased at pre-partum, increased at post-partum and was significantly (P<0.01) higher in T2 followed by T1 and C. TBARS level was significantly (P<0.01) lowered in T1 and T2 compared to control at postpartum. Result indicated that amelioration of heat stress by supplementation of Zn through reduced cortisol, TBARS and improved T 3 & T 4 concentration. Key words: Cortisol, Heat stress, TBARS, Zinc. Abbreviations: C: Control, T1: Treatment 1, T2: Treatment 2, KF: Karan-Fries TBARS: Thiobarbituric Acid Reactive Substances, T 3 : Triodothyronine and T 4 : Tetraiodothyroxin INTRODUCTION In dairy cattle, peri-parturient period is a critical period for growth of fetus and physiological transition into the next lactation. Environmental factors, such as temperature and light, exert significant effects on the production, health and immunity of animals during this period and after parturition. Crossbred cattle are more susceptible to physical distress when exposed to heat stress as compared to other farm animals. Heat stress in dairy cows is caused by a combination of environmental factors (temperature, relative humidity, solar radiation and air movement). Heat stress is one of the wide varieties of factors which cause oxidative stress in-vivo. Reactive oxygen species (ROS), the major culprits for causing oxidative stress, are constantly generated in vivo as an integral part of metabolism. ROS may cause oxidative stress when their level exceeds the threshold value. They trigger progressive destruction of polyunsaturated fatty acids (PUFA), ultimately leading to membrane destruction. Zinc is an essential nutrient and a very important trace element involved in a wide range of activities. It acts as cofactor for more than 200 enzymes and promotes biochemical reactions in body (Abdel Monem et al., 2011). One of the most important functions of zinc is its participation in the anti-oxidant defense system. It is a required component of the antioxidant enzyme superoxide dismutase and is needed for the synthesis of metallothionein, which may scavenge free radicals (Spears et al., 2008). Zinc deficiency increases oxidative damage of cell membranes caused by free radicals (Prasad et al., 2002). The major sources of Zn in the mineral supplements formulated for animal feeding are inorganic salts like Zinc sulphate (ZnSo 4 ), Zn oxide (ZnO), Zn chloride (ZnCl 2 ) (Grace et al., 2012). Metabolic hormones, such as thyroxine, triiodothyronine, can be used to indicate metabolic changes in relation to altered feed intake during heat stress condition. Plasma cortisol concentrations have been used as physiological markers of stress. Very scarce literature is available correlating Zn supplementation with hormonal and lipid peroxidation status especially in crossbred cattle. Therefore, the present investigation was undertaken to assess the effect of zinc supplementation on hormonal and lipid peroxidation status of peri-parturient Karan Fries cows during heat stress condition. MATERIALS AND METHODS Ethical approval: The experiment was approved by the Institutional Animal Ethics Committee constituted as per the article number 13 of the CPCSEA-rules, laid down by the Government of India. Study area: The experiment was conducted at Livestock Research Centre, National Dairy Research Institute, (NDRI) Karnal. Karnal is situated at an altitude of 250 meter above