Blue-green algae toxicosis in five dairy cows

Five Holstein cows developed a sudden clinical syndrome of ataxia, muscle tremors, recumbency, and bloody diarrhea. The pond where these cows obtained water contained a near pure culture of Microcystis aeruginosa, a toxic blue-green algae. All cows affected were treated with activated charcoal, procaine penicillin, glucose, and calcium and magnesium gluconate. All 5 cows were clinically normal ten days later. Many practicing veterinarians regard blue-green algae toxicosis as a rare syndrome that results in rapid death for consuming animals; however, this toxicosis may be common and not lethal. Because no diagnostic test is available for blue-green algae toxicosis, this condition rarely is diagnosed.