BOVINE RESPIRATORY DISEASES

Bovine respiratory diseases affect their respiratory system. They account for mortality during allotment, reduce the performance of the farm and often entail costs for the breeder.

The affected animals may have general symptoms: fever, weakness and loss of appetite. Respiratory symptoms are also observed: respiratory difficulties, cough and nasal discharge.


WHY?

Respiratory diseases in bovines in breeding are caused by several factors: pathogenic agents (viruses, bacteria, parasites, fungi) benefit from factors in the surroundings and in a particular animal (poor immunity of the respiratory system in calves under one year old)1 and colonise the bronchi and lungs in susceptible animals.



WHAT ARE THE SOLUTIONS?

The management of bovine respiratory diseases consists of prevention, for example hygienic measures in buildings, ventilation, restricting stress and vaccination.
Once it has appeared, the disease requires the use of appropriate antibiotics, anti-inflammatory agents and symptomatic treatments if necessary (bronchodilators, diuretics).


WHAT ANIMALS ARE AFFECTED?

Bovine respiratory diseases mainly affect young animals: calves intended for fattening (in which case it is called ‘shipping fever’) and replacement flocks (in which case it is called enzootic infectious bronchopneumonia).

The prevention of the disease involves putting several factors under control. In particular, it is advisable to strengthen the weak immunity of the calf, which makes it vulnerable. Prevention is also based on controlling the parameters of the environment and stress factors.
An essential part of treatment is appropriate targeted antibiotic therapy, as well as anti-inflammatory treatment. Symptomatic treatments can also help enhance the everyday comfort of the affected animals.
The measures of prevention and treatment must be adapted to the specific features of a particular farm.

FIND OUT MORE ABOUT BOVINE RESPIRATORY DISEASES

HOW IT COMES ABOUT

Bovines under one year old have an immature respiratory system1, which is not yet able to effectively fight infectious agents and the associated inflammation.

First, the virus makes use of this weakness to settle in the respiratory system. Then it causes lesions, which further weakens the local immune defences. Later, the bacteria can colonise the trachea, bronchi and lungs, leading to further harm.2

If the inflammation and infection persist (no or failed treatment), the disease may progress to become chronic. The bacteria may enter the blood and settle in other structures, in particular the joints, which are especially vulnerable. Thus, among the complications of bovine respiratory diseases is septic (infectious) arthritis (inflammation of the joints).

ANIMALS AFFECTED

The animals affected are mainly calves and young bovines (under one year old). The main reason is their immature respiratory system.

Another one is their immature immune system. Protected by antibodies it received from the mother with the first milk (colostrum) over about 2–4 weeks, the calf’s immune system only takes over from the age of 1 to 2 months. Therefore, the calf is not protected from infectious agents in this time period.

On the other hand, calves are especially susceptible to environmental factors, such as temperature, ventilation, humidity, dust, level of hygiene in the building and litter box, etc.

Finally, when they are collected in groups for fattening, this is a source of stress (manipulations, transportation, changes in the diet, contact with animals from other farms), which increases the risk.

PREVENTION

Some factors driving the disease can be controlled, in particular those related to the surroundings. Proper design of the farm buildings allows for a better control of the temperature, ventilation and humidity. Prevention also comprises good management of the population density, distribution into groups and the possibility to quarantine animals that are sick or were recently brought to the farm.

Stress factors can also be minimised by making manipulations gentle and disturbing the animals as little as possible. Another point to improve would be the transportation conditions during allotment.

When managing a farm, the breeder can take certain actions to minimise the risks: optimise in which season calving takes place, improve the methods of straw spreading, begin food transitions when diet is changed, and include supplements with oligoelements and vitamins in the diet.

More specifically, prevention also includes vaccinating the flock (including the young) against the circulating pathogenic agents and ridding the mother cows and calves of parasites. Finally, a separate and priority factor is that it is essential for newborn calves to receive colostrum of sufficient quality and quantity as early as possible, as it is rich in antibodies and factors of immune response.

TREATMENTS

Most often, the disease is triggered by a virus. However, bacterial superinfections are extremely common, so antibiotic treatment targeting the involved bacteria is most often needed.

Anti-inflammatory treatment is also recommended, since it fights fever, improves respiration, increases appetite and reduces the risk of lesions of the lungs (which cause respiratory difficulties in the longer term)3, 4.

However, it should be kept in mind that some anti-inflammatory agents can cause digestive (abomasal ulcers) and, more rarely, renal disorders (renal insufficiency).

Finally, symptomatic treatments may be indicated when there is severe bronchial inflammation (bronchodilators) or pulmonary oedema (diuretics).