Several years ago, Jim Wasson, DVM, Armour Veterinary Clinic, Armour, S.D., had a client with beef cows grazing late fall pastures. Cows drank out of a dug-out, and when it would freeze, the water was chopped to allow access. One of the owners put out salt and mineral to the cows. The weather worsened and the cattle had limited water. The cows were brought back to the producer’s operation and put in a dry lot with a water fountain.
Wasson notes that on the way to the producer’s operation, two cows collapsed and died. A post mortem was unremarkable, and Wasson says they were older cows and were full of dry roughage and at the time their age and possible impaction of the dry forage was considered. Two to three days later, however, another cow died in the dry lot. Wasson notes that though the cows had access to a water fountain, their unfamiliarity with it caused many to not drink water.
At this point the dead adult beef cow was taken to the Animal Disease Research and Diagnostic Laboratory in Brookings, S.D., for examination. Veterinary pathologist Dale Miskimins, DVM, MS, reports that no significant gross lesions were observed in the cow. Discussions with Wasson revealed the fact that the cows had eagerly consumed salt when they arrived at the home farm but were limited in their water consumption. Chemical analysis of brain tissue revealed 2,050 ppm sodium. These results confirmed salt toxicity/water deprivation. Levels above 1,800 ppm in cerebral tissue are sufficient to make a tentative diagnosis. No further losses were reported.