TY JOUR TI SEASONAL CORTISOL LEVELS AND VARIABILITY IN ROMANOV SHEEP IN WESTERN SIBERIA KW cortisol KW hormones KW season of the year KW blood serum KW sheep KW Romanov breed JO Bulletin of KSAU AU Tarasenko, E.I. AU Sebezhko, O.I. AU Morozov, I.N. PY 2025 IS 0 PB Krasnoyarsk State Agrarian University