Pneumonia: reduce the risk factors and enhance immunity
This week we look at the risk factors involved, and how to best prevent the disease.
Risk factors for pneumonia are anything that decreases the animal’s immunity, and consequently their ability to fight infection, or anything that increases the animal’s exposure to the infectious agents.
* Stress: Anything causing stress on an animal lowers its immunity. Examples would be a day at the mart, transport, changing environment.
Poor air quality due to bad ventilation, poor housing design, or overcrowding.
Mixing groups of animals, such as different groups of weanlings bought in and mixed together. One group previously exposed to a virus like IBR, which have immunity, may start shedding the virus when stressed and cause disease in the other cattle.
Housing animals of different age groups: this can cause problems for the same reasons as above.
Dairy heifers reared on an out-farm or contract reared, joining the main herd the winter before calving, or after calving, can lack immunity to pneumonia pathogens that exist in the main herd.
Lung worm: a heavy lung worm burden can cause hoose pneumonia, but also makes cattle more susceptible to viruses and bacteria that cause pneumonia.
Prevention of pneumonia is based on reducing the risk factors and enhancing immunity.
When buying in weanlings from the mart, it is difficult to avoid stress and exposure to other cattle, and the diseases they may be carrying.
Buying stock privately can eliminate some risks. Either way, it is essential newly purchased stock arrives to a suitable environment, be it a sheltered paddock if the weather is suitable, or a well-ventilated shed with a straw bed and easy access to feed and water.
It can be difficult to avoid mixing home-bred cattle with bought-in cattle, or different age groups.
However, whatever the circumstances, it is essential to avoid overcrowding and to ensure adequate ventilation. Small changes to existing sheds can make a big difference to the ventilation, like lifting the sheeting away from a side wall.
Vaccination offers a means of priming the animal’s immune system before it meets a challenge. In terms of vaccination, there are effective vaccines available against IBR, RSV, PI3, mannhaemia and histophilus.
In general terms, vaccines can be divided into intranasal and injectable vaccines.
The intranasal vaccines stimulate good immunity quickly (three to seven days) and are suitable for use in the face of an outbreak of pneumonia. The immunity following intranasal vaccination, however, tends to be relatively short acting (three to four months).
In contrast, injectable vaccines may take three to four weeks (with a two-injection course) to stimulate maximum immunity, but it is longer lasting (six months for IBR and up to 12 months for other pathogens).
Working with your own vet, a vaccination protocol can be constructed that best suits your farm.
With bought-in cattle, a protocol that protects the animals from the main pathogens quickly can be used.
But no vaccine gives 100% protection and, with respiratory disease, if housing, ventilation and stocking rates are not optimal, vaccine efficiency will be reduced.
As with all vaccines, adherence to correct storage and administration guides is essential for the desired outcome.
