The Value of Clean Water by Nancy S. Loving, DVM


By Nancy S. Loving, DVM


Water is the most essential nutrient available to animals. Domestic animals can go for many weeks without food but cannot survive even a week without water. Would you drink the water that is accessible to your animals? This caveat serves as a useful guideline for what to offer. 


Every season brings with it challenges for maintaining clean and wet water. Do you find yourself spending a lot of time managing your horse’s watering system? Are you lugging hoses and buckets around in warm weather, and procrastinating about scrubbing away debris and slimy algae growth? Do you need an axe to break up tank ice in winter? These issues are labor and time intensive but necessary with many conventional water systems. 


Just as importantly, dirty water can be the source of many health problems in horses.


Diseases that Result from Dirty Water


Most water systems for horses and livestock need steady maintenance to eliminate collections of debris and algae overgrowth. Blue-green algae (cyanobacteria) is known to be toxic if ingested. Water contaminated by excess nutrients, such as nitrogen and phosphorus from manure and/or runoff of fertilized fields, is prone to developing algal blooms in warm weather. While most common in ponds and slow-moving water, algal blooms also occur in water tanks and systems that are cleaned infrequently. It is not always possible to visualize the presence of this lurking danger. Algae neurotoxins cause affected horses to develop muscle tremors, respiratory distress, seizures, hypersalivation, and diarrhea, with the potential for rapid death. Other cyanobacterial toxins cause liver disease or colic.


Another critical concern about stagnant water is its role as an attractive mosquito habitat, which can amplify the presence of mosquito-borne viral encephalitic diseases. Mortality rates of Eastern equine encephalitis (EEE) run as high as 90%. Western equine encephalitis (WEE) is less fatal but still kills 40-50% of infected horses. West Nile virus (WNV) mortality rate is around 33% and of those horses that recover, about 40% experience a persistent neurologic deficit. Since 1999, there have been nearly 170,000 reported cases of West Nile virus in the USA. Unvaccinated horses throughout the entire continental United States are at risk of contracting at least one of these neurologic viral diseases.


Another water-borne disease that affects horses is leptospirosis, which is shed in large quantities from an infected animal into urine, milk, or tissues of an aborted fetus or placenta. In contaminated, slow-moving or stagnant water, leptospirosis organisms survive for weeks. Throughout the USA, 75% of horses show a positive titer in blood tests for this disease. This does not mean the horse is infected; just that it has been exposed with the potential for infection. An infected horse develops fever, loss of appetite, depression, and generalized pain, while some cases progress to eye inflammation (uveitis), kidney disease, or abortion.


Cryptosporidiosis is a protozoal disease obtained through manure-contaminated water or feed. As many as 38% of horses are affected by it world-wide. “Crypto” causes diarrhea and weight loss, with foals particularly at risk.


Potomac Horse fever, a serious diarrheal disease caused by Neorickettsia risticii, is also associated with water sources. Caddis fly and other aquatic insect larvae (cercaria) serve as natural vectors for this bacterial disease. Snails release cercaria containing the infectious agent; these are consumed by aquatic insects, which hatch and emerge from the creek, river or ditch water. A horse ingesting these insects (in contaminated water, and also hay and pasture) becomes infected. Dirty water also is likely to harbor dangerous levels of coliform bacteria, such as E. coli or Salmonella, which can cause serious and potentially fatal diarrhea and intestinal illness.


Sulfates, recognized by a rotten egg stench, and mineral salts and nitrates are examples of total dissolved solids (TDS) that increase water salinity. Manure and fertilizers are common sources of TDS. The unpalatability of water with high levels of TDS may impact how well a horse is willing to drink due to an “off” taste. Pesticides and herbicides also can contaminate horse watering areas. If no other water source is available, horses will drink contaminated water but not necessarily at needed levels in hot weather. Besides dehydration, drinking dirty water can lead to diarrhea, intestinal illness, and even death. And, limited water intake tends to decrease feed consumption and body condition.


Besides these important disease concerns, the biggest problem with dirty water is that horses may object to it and if they don’t drink sufficient amounts of water, they develop dehydration and impaction colic. In my experience as an equine veterinarian for 34 years, this has been the primary problem with unpalatable water. Colic incidence ranges from 4-10% of all horses, and of these, about 10% involve an impaction. 


Prevention of many these illnesses is possible with the right water system that enables and encourages horses to drink clean, pure water.


An Optimal Water System

Finding a simple water system that keeps water clean, wet, and safely free of contaminants and pollutants is a real time saver while optimizing the health of your horses. The Drinking Post is a commercial system that eliminates many management headaches and dangers of water provision to your animals. The source of water coming through the pipe determines its purity. The system can be plumbed directly into a reliably clean water source from a pressurized line so there is no chance for contamination by manure, fertilizer, or disease organisms.


Water is delivered to a drinking bowl through an on-demand system activated as the horse’s nose pushes on a paddle to get a drink. Once finished, a half-pint or less of water drains out of the bowl through the interior of the unit into a bed of washed rocks beneath the post. Much like a frost-free hydrant, a valve in the riser pipe drains any water remainder into a gravel bed to below frost level. The ground area around the riser pipe and drinking bowl remains dry but clean, cool water is available for the next on-demand drink. 


The net result is that there is no algae growth in the water bowl and no need to scrub away debris. No water remains behind in which mosquitoes can breed. With no need for electricity, there are no electricity bills to keep water “wet,” no concerns that power outages could affect water delivery, no chance for an electrical fire related to faulty wiring, and no chance of a horse being shocked by a tank heater or inadvertently biting into an electrical line. Water delivered from below frost level remains around 50 degrees year-round with no need for insulation. And, this system obviates the need for hauling around buckets and hoses. Besides curtailing your labor-intensive maintenance efforts, the best benefit of all is that your horses have full-time access to ample, clean water to promote overall health and body condition.

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