Blue-green bacteria in natural bodies of water produce toxins that affect horses’ nervous systems and liver.
TIPS TO IDENTIFY BLUE-GREEN BACTERIA (ALGAE)
1. STICK TEST: The bacteria aren’t easy to pick up. If you run a stick through the water, it will come out clean or with a thin coat covering the stick.
2. MIXES: The bacterian can appear to be mixed in with the water, changing the color of the water to a bright pea soup.
3. GREEN RING: If the bacteria have formed a green ring at the top of the water, perform the stick test. The bacteria bloom doesn’t always affect the entire water source. It can sometimes cover smaller areas of the water.
4. DEAD FISH: The toxins can affect fish, and you may see dead fish floating in the water.
Can or should you treat a Blue-Green bacteria bloom? The Wisconsin Department of Natural Resources tells us, No. Treatment of surface water experiencing blue-green bacteria bloom with an herbicide or algaecide may kill the blue-green algae, but any toxin(s) contained in the cells will be released at once, resulting in a overload of toxin(s) in the water. So while the bloom may no longer be visible, toxin(s) may be present for some time following treatment. It is best to stay out of [and keep horses away from] water experiencing a bloom and wait for the bloom to dissipate on its own.
SIGNS OF HORSE POISONING
Horses who consume the toxic water may show signs of colic and diarrhea. Death can occur within minutes or a few hours.
POISONING PROGNOSIS FOR HORSES
The prognosis for a horse exposed to blue-green algae is not promising. Treatment is limited to supportive care. Occasionally, horses can recover, but death typically occurs so quickly that the animals are found deceased near the water source.