Dietary potassium-sodium imbalance as a factor in the aetiology of primary ruminal tympany in dairy cows.

Results of an investigation into the chemical composition of pasture herbage on twelve New Zealand dairy farms, with contrasting incidences of primary ruminal tympany (bloat), are presented. The data suggest that dietary K;Na ratio may be an important factor in the aetiology of bloat; a factor that does not seem to have been recognised in the past. Other supportive evidence for this hypothesis is briefly discussed.