By Dr Jolly Kabirizi
This pulmonary disease, associated with the movement of adult cattle to lush green pasture, is historically referred to as “fog fever” (i.e., post-harvest regrowth or aftermath of hay or silage production).
The disease occurs when cattle are moved from pastures during the long dry season onto lush pastures in the wet season.
The lush pasture may be of any variety of grass, alfalfa, rape, kale and turnip tops. When seen, it is frequently associated with annual forage cropping methods designed to extend grazing in the fall.
The composition of the rumen microflora is important in the development of pulmonary emphysema.
A low plane of nutrition is believed to alter the rumen microflora to one that is favourable to the abnormal growth of clostridial organisms.
Symptoms include difficulty breathing, reluctance to move and extreme weakness. Death may occur within a few hours after onset of the disease.
A gradual transition to lush pasture or the continuation of hay feeding, while cattle acclimate or adjust to lush pasture, is advised.
