By vet Catherine Davies
Respiratory disease remains one of the most common and costly health problems affecting calves on UK farms.
Often grouped under the term “calf pneumonia”, respiratory disease can have a significant impact not only on short-term calf health and welfare, but also on long-term performance, milk yield and farm profitability.
Calf respiratory disease is usually caused by a combination of infectious agents and management factors.
Viruses such as RSV (respiratory syncytial virus), IBR and PI3 frequently damage the calf’s airways first, reducing natural defences and allowing bacteria such as Pasteurella, Mannheimia, Histophilus or Mycoplasma to establish infection in the lungs.
Stressors such as poor ventilation, overcrowding, mixing age groups and nutritional challenges all increase the risk.
One of the biggest challenges with respiratory disease is early detection. The first signs are often subtle: calves may be slightly dull, have reduced milk intake, or breathe a little faster than normal. As disease progresses, coughing, nasal discharge, fever and increased breathing effort become more obvious. By the time these signs are easily noticeable, lung damage may already be present.
The cost of pneumonia extends well beyond treatment. Affected calves have reduced growth rates, take longer to reach breeding weight and often produce less milk in their first lactation. Studies have shown that heifer calves that suffer pneumonia early in life can decrease milk production in their first lactation by up to 500 litres. For beef systems, reduced daily liveweight gain and poorer feed efficiency quickly erode margins.
Prevention starts with good calf immunity. High-quality colostrum, given in adequate volume and as soon as possible after birth, is one of the most effective tools available to farmers. Calves with poor colostrum intake are far more likely to develop respiratory disease. Regular monitoring of colostrum quality and passive transfer success can highlight problems before disease becomes widespread.
Housing and ventilation are equally important. Fresh air is essential, but draughts at calf level must be avoided. Many cases of pneumonia can occur not because it is too cold, but because stale, damp air allows pathogens to build up. Simple measures such as adjusting inlets, improving outlets, or reducing stocking density can make a significant difference. Individual hutches or well-designed group housing can both work, provided airflow and hygiene are managed properly.
Nutrition also plays a key role. Calves need enough energy and protein to support growth and their immune system, particularly during colder months. Calves not receiving adequate nutrition are less able to fight pneumonia and recover slower. Clean water should be available from an early age, alongside a consistent feeding routine.
When disease does occur, early treatment is crucial. Prompt identification of sick calves, accurate temperature checking and working with your vet to select appropriate treatments will improve outcomes and reduce the risk of chronic lung damage. Repeated treatments or poor response to antibiotics should always prompt a review of diagnosis and management.
Vaccination can be a valuable part of a respiratory disease control plan, but it is not a standalone solution. Vaccines work best when combined with good colostrum management, low stress housing and strong biosecurity. Your vet can help design a vaccination programme tailored to the specific challenges on your farm.
By focusing on prevention, early detection and consistent calf management, farmers can significantly reduce its impact, improving both animal welfare and the long-term productivity of their herds.