Administration of the homologous natural gamma-interferon for prophylaxis of infectious diseases showed that 2-3 injections of gamma-interferon prevented infectious morbidity of more than 90% of sucking pigs and new-born calves, sharply increased their preservation to 90% and above, increased their productivity by 1/3. In conditions of industrial growing of young animals therapy by this preparation of pigs and calves with colibacteriosis and parainfluenza in comparison with control significantly decreased mortality of morbid young animals, accelerated their recovery and promoted the weight gain in pigs and calves.