Pasteurellosis and Pneumonia in Sheep by Mei Thum, CLFS

The infection had caused pneumonia in the ram, a condition which had also affected a few of the young animals on the farm this year. Pasteurellosis is a serious problem and one of the most common causes of mortality in sheep, hence early treatment is imperative.

Pasteurellosis as (Brooks, 2022) explains, is a bacterial infection which affects the lower respiratory tract. It is caused by the bacteria Pasteurella haemolytica. Pneumonia, an inflammatory and sometimes fatal condition affecting the lungs, is often triggered by an infection. Pasteurellosis is one of the most common causes of pneumonia and so is a serious problem amongst herd animals such as sheep where bacterial infection is easily transmitted through the flock.

The cause of pasteurellosis is usually due to a variety of factors such as cold, damp weather, poor ventilation, moving from field to field and any general stress. A combination of these factors will significantly increase a sheep’s susceptibility to infection.

Although the initial symptoms of pasteurellosis are subtle such as laboured breathing, fever and coughing, it is important to begin treatment in the early stages of the infection before lung damage begins to occur. The earlier the treatment is administered, the higher the likelihood of survival for the sheep. Some farmers choose to implement antimicrobial treatment for all sheep in the months where pasteurellosis is most common, however the economic cost of this prevents many farmers from doing so.

Treatment usually consists of an antibiotic such as tetracycline accompanied by an anti-inflammatory. These tetracyclines are usually long-acting and administered by the intra-muscular route, often in the neck if the treated sheep is going to be sent to market as larger muscles such as the rump should be untouched to remain in the best condition possible.

Overall, pasteurellosis can be successfully cured if treated early, which is important in order to prevent the onset of pneumonia or spreading of the infection through the flock. It is therefore best for farmers to be vigilant, perhaps implementing preventative measures to avoid the infection as best possible.

Brooks, K. M., 2022. Pasteurellosis of Sheep and Goats. MSD Veterinary Manual .