TY JOUR TI THE DANGER OF MIXED VIRAL INFECTIONS IN CALVES OF YOUNGER AGE GROUP KEPT IN LIVESTOCK FARMS KW immunity KW infection KW viral infections KW calves KW mixed infections JO Bulletin of KSAU AU Belousova, E.V. AU Chkhenkeli, V.A. AU Kalinovich, A.E. PY 2016 IS PB Krasnoyarsk State Agrarian University