Calf Pneumonia

Calf Respiratory disease (Pneumonia)

There are two distinct respiratory syndromes - acute (calf or enzootic) pneumonia which is usually more sudden in onset or chronic pneumonia which is more insidious in onset.

Prevalence and causes

Pneumonia usually occurs in young housed calves (five weeks to five months old) either being reared as dairy replacements or in beef systems, usually reared indoors.

The aetiology (cause) is very complex and usually multifactorial involving infectious agents, the environment and the immune status of the animals themselves. Infectious agents involved include Mannheimia haemolytica, Haemophilus somnus, Infectious Bovine Rhinotracheitis (IBR),  bovine Respiratory Syncytial Virus (RSV) and Parainfluenza III Virus (PI3), along with many other bacteria and mycoplasma species and viruses.

Environmental factors include low environmental temperatures and high humidity and poor ventilation and also direct draughts onto calves themselves. The relationship between season and outbreaks may also be related to management practices including calving pattern and mixing of different ages of calves.

There may be breed differences in susceptibility to calf pneumonia and colostrum status and time of weaning can all affect immune status of the calf. Stresses such as mixing groups, movement and poor housing conditions can also affect immune status.

What are the clinical signs of the disease?

Acute pneumonia is usually noticed as a reduction in feeding by the calf, dull demeanour, dropping of the head, increased respiratory rate, nasal discharge and/or a cough along with a pyrexia (elevated temperature).

Chronic pneumonia is more gradual in onset with no distinct ill phase and the cow may appear to still eat well but may have a slight nasal discharge, sometimes with an increased respiratory rate and cough.

Both forms of the respiratory disease cause production losses as there is a reduction in liveweight gain and there may be deaths in the acute syndrome. Veterinary advice should be sought in order to discount other possible causes (eg, congenital disease, tuberculosis (TB)) and to discuss treatment and vaccination and management strategies.