Effects of Housing Systems on Cortisol Concentration of The Gilfs Raised in Group

Abstract

      The study was conducted to determine the effects of two housing systems on cortisol concentration of gilts. A total of 20 F1 (Landrace x Yorkshire) gilts with similar body weight and age were randomly allotted into four pens of two group-housing systems (two pens with outdoor yards and the other two without yards, 5 gilts per pen). Saliva cortisol concentration on the days 1, 3, 7, 15, 30, 50, and 80 and plasma cortisol concentration on the days 1, 3, 15, 30,and 50 of the gilts after grouping wase determined by ELISA test and ECLIA (Electrochemiluminescence Immunoassay) using COBAS system, respectively. Results showed that there were no significant differences in saliva and plasma cortisol concentration of the gilts between the two housing systems (P > 0.05). However, in each housing system, saliva cortisol concentrations on the days of grouping were significantly different (P < 0.05). Cortisol concentration of the gilts in both two housing systems was highest on the 1^st day after grouping (0.58 μg/ dL in the pens with yard and 0.59 μg/ dL in ones without yard), gradually decreased on the 3^rd day (0.48 μg/ dL and 0.46 μg/ dL) and was lowest and stable on the following days. Similarly, in each housing system, plasma cortisol concentration taken in the days 1, 3, 15, 30 and 50 after grouping was significantly different from each other (P < 0.05). Plasma cortisol concentration was highest in the 1^st day after mixing (7.38 μg/ dL in the pens with outdoor yard and 7.17 μg/ dL in the indoor pens), followed by the 3^rd day (5.35 μg/ dL and 5.19 μg/ dL), then gradually decreased and stable in the following days. A positive correlation between plasma and saliva cortisol concentration was found ( r = 0.73).