Calves from one day to five months of age are particularly susceptible to pneumonia. In the latest California Dairy Newsletter, Pat Blanchard with the California Animal Health and Food Safety Laboratory discusses three main categories of lung infections in dairy cattle. They are:
- Bronchopneumonia. Occurs from inhalation of bacteria or viruses into the lung. This type of pneumonia usually affects the front and lower parts of the lung. Bacteria, particularly Mannheimia, Pasteurella and Mycoplasma, are the most commonly found infectious agents in this type of pneumonia.
- Interstitial pneumonia. Occurs most often due to Salmonella Dublin (aka Salmonella group D1 or S. Dublin). This bacteria spreads to the lung through the blood, so it affects all the lung lobes equally.
- Aspiration pneumonia. It is observed after a calf or cow inhales fluid, feed or milk into the lung. This can occur from a misplaced esophageal feeding tube. Also, when calves are very weak from diarrhea or a prolonged birthing, they may have a poor swallow reflex, so fluids placed in their mouth (milk or colostrum) may accidentally enter the trachea, settling in the lung.
In the newsletter article, Blanchard provides a chart that shows a breakdown of common agents found in 130 pneumonia cases from October to December 2011.
Source: California Dairy Newsletter, February 2012