Several cattle in Alberta and Sask-atchewan have died recently from fog fever, otherwise known as bovine atypical interstitial pneumonia.
The illness occurs when cattle are put into lush pasture after coming off dry pasture. The typtophan in rapidly growing pasture grasses converts in the animals’ rumen, leading to sudden onset, minimal coughing and either death or dramatic improvement within a few days.
Barry Yaremcio, beef and forage specialist with Alberta Agriculture, said fog fever is uncommon, and treatment options are limited other than to avoid putting adult cattle into lush pasture. Calves are not affected.
Fog fever can occur five to 10 days after the pasture change. Mild cases can go unnoticed.
Severely affected cattle breathe through their mouths, extend their tongues and drool.
Yaremcio said feeding monensin or lasalocid to cows before turning them into lush pasture may prevent fog fever, but those treatments have no effect after onset of symptoms.
