Environment, germs and immunity are top of mind when thinking of all the risk factors that could set the stage for pneumonia in cattle. The forgotten factor is one beyond producers’ control and the reason why pneumonia will always be a problem — anatomy.

Bovine lungs are very small relative to the animal’s oxygen requirements, explains Dr. Edouard Timsit, University of Calgary Veterinary Medicine and a veterinarian with Feedlot Health Management Services at Okotoks.

The total lung capacity of an adult cow is only 2.5 times greater than that of an average man, yet its resting oxygen requirement is more than 10 times greater. A cow’s lung capacity is 12 litres, its resting oxygen requirement is 124 litres per minute and it takes 30 breaths a minute to meet this demand. Compared to a species of similar size and structure, a horse’s lung capacity is 42 litres and its resting oxygen requirement is 49 litres per minute requiring only 11 breaths per minute.

The high airflow rate coupled with weaknesses of the bovine lung structure itself leave ways for bacteria, viruses and other contaminants to penetrate deep into the lungs where they trigger infection and inflammation.