As summer health warnings come out cautioning recreationists about algal blooms on area lakes, Wisconsin farmers may want to prevent access to ponds to decrease the potential for livestock toxicity from cyanobacteria, also known as blue-green algae.  Blue green algae are naturally occurring in many ponds during the summer months, and hot, dry conditions seem to stimulate algal blooms. Although not common, livestock can be poisoned from drinking or wading (then grooming themselves) in ponds with heavy algal blooms.  Cattle, sheep, pigs, horses, dogs, even waterfowl, may be at risk for poisoning from blue green algae, with the toxins attacking the nervous or liver systems.

Unfortunately, sudden death may be the first indication of toxicity.  Animals found dead in or near ponds or other water bodies should be examined by a veterinarian to rule out other causes and water samples are recommended to confirm suspicion of cyanobacteria. Other symptoms of poisoning include muscle tremors, difficulty breathing, and convulsions.

 Prevention is the key to management, especially during high temperature periods when blooms are likely:

• Develop alternative water sources to provide animals with adequate amounts of clean, good quality drinking water at all times, and especially during hot weather
• Check ponds that livestock have access to regularly; consider fencing to prevent direct access. Ponds are also a potential source of animal diseases like leptospirosis and coccidiosis
• Do not allow animals to drink from directly from ponds or use downhill tanks filled from the pond unless the water is pumped from deep within the pond when algal blooms are present

 For more information about blue green algae here in Wisconsin, see: Blue Green Algae quick facts from WI DNR