Dr. A. Morrie Craig oversaw a veterinary toxicology laboratory that served the research community across the Pacific Northwest. For his graduate dissertation, Dr. A. Morrie Craig wrote on “Cattle Grazing and Behavior on a Forested Mountain Range and Their Relationship to Acute Dietary Bovine Pulmonary Emphysema (ABPEE).”

A relatively common cause of adult beef cattle’s acute respiratory distress, ABPEE has characteristics of sudden onset and minimal coughing. Within several days, the disease typically resolves in either rapid health improvement or fatality. It tends to involve groups of cattle and may affect as many as 50 percent of animals in a herd. However, only a small percentage of animals will feel severe respiratory distress.

Most commonly, ABPEE occurs in the autumn months, within five to 10 days of moving to a lusher pasture area with a wide range of grasses and forage, such as kale and alfalfa. This abrupt change causes ruminal fermentation, and 3-methylindole (3MI) formation, with this toxic substance metabolizing in the lungs.

One reason for ABPEE’s appearance is that cattle tend to overeat after a summer relegated to dry or overgrazed pasture. To counter this, ranchers often institute a grazing transition period in which they provide the cattle with supplementary feed or hay before moving them to lusher pasture. In addition, prophylactic antibiotics in dietary monensin can help lessen the chance of 3MI formation.