In dairy cattle farms, diarrhoeal diseases of calves are the most common health problem during the milk nutrition period, which directly affect the economic profitability of the farm. The paper is focused on the issue of the importance of infectious diarrhoea of calves during their rearing. Rearing healthy calves requires achieving maximum levels of the passive and the active immunity. Strict adherence to the principles of prevention, prophylaxis and biosecurity reduces the infectious pressure, incidence and severity of diarrhoeal diseases. The treatment is based on early rehydration of the body, which in turn leads to a reduction in the use of antimicrobials and a reduction in the risk of developing antimicrobial resistance.