Horse Mortality

Karen Woodmansee's article Two sides of the wild horse issue, Nevada Appeal, May 2, 2008, included a quote from a Virginia Highlands resident who complained of seeing three apparently starving horses that couldn't stop walking, were running into tree stumps and "weaving." That is not how starving horses behave. Those are classic signs of West Nile Virus.

West Nile Virus is a mosquito borne disease that primarily infects birds, but it can also infect horses and humans. Horses and humans are end hosts so they can't pass the virus along, even if bitten by mosquitos. But the virus stage in birds is highly contagious and a mosquito biting an infected bird can spread the disease to horses and humans. The public health warnings from the Center for Disease Control (CDC) are to use mosquito repellent, eliminate mosquito breeding sites, install or repair window and door screens, and support community-based mosquito control programs.

Here are the symptoms of West Nile Virus as described by the CDC.

• high fever
• headache
• neck stiffness
• stupor
• disorientation
• coma
• tremors
• convulsions
• muscle weakness
• vision loss
• numbness and paralysis

These symptoms may last several weeks, and neurological effects may be permanent.

Wild horses obviously don't get vaccinated for West Nile Virus and are vulnerable to the disease. The Virginia Range Herd as a whole is pretty healthy and remarkably few horses exhibit serious symptoms, although it is probable that many horses have been bitten by infected mosquitos as horses typically have to drink where birds also drink and mosquitos breed.

A horse coming down with a serious case of West Nile Virus will exhibit the signs described in the Woodmansee article as well as those listed on the CDC's symptom's list. Most horses will survive so long as they don't get dehydrated, although they can lose a lot of weight while they fight the disease. These horses are difficult to trap and remove as they tend to stumble around, panic and get all tangled up in the trap corral.

This is a situation where providing temporary water near the horses is appropriate until the horses recover. Some horses have such stiff necks that it is difficult for them to reach down into ponds or streams to drink, even if they could walk the distance to water. A good temporary water source is a plastic 55 gallon drum with one end removed and kept filled with clean water. We also strongly recommend placing a "mosquito dunk" in the water to prevent mosquitos from breeding in the drum. We certainly don't want to increase the mosquito problem!

The Virginia Range Estray Program Manager should be notified of any sick horses and should approve the location of any temporary water supply. The Manager's involvement is important in order to ensure the safety of both horses and people. Temporary water supplies should be discontinued as soon as the horses are healthy enough to return to their instinctive eating and drinking patterns.

A surprising number of Virginia Range horses survive West Nile Virus. Those that die are most often "elderly," very young or weakened by some other condition.

Starving horses

Apart from diseases such as West Nile Virus, aging has its affect on horse weight. Even domestic horses reach an age where it becomes harder for them to maintain their historic body weight. Their teeth wear down and are less effective at grinding grasses into a more digestible form. Their digestive system itself may be less efficient. The typical "end stage" of the wild horse's natural life cycle involves weight loss and death.

Even a weakened adult horse is difficult for most predators in the region to take down, so we're more likely to notice sick or elderly horses than we would deer and smaller animals that the coyotes can easily dispatch and consume.

Until someone comes up with an elder care program for wild horses, we'll always have a few skinny older horses around us.

The Department of Agriculture acts as if anyone without letters after his/her name is ignorant, those with letters after their names who don't agree with the Department just don't know what they're doing, and someone who dares to challenge NDoA's logic is a threat to the agency.

Wildlife ecologists often offer a simple observational technique that isn't formal but is practical and pretty accurate.

Look at all the members of the bands, especially the stallion and yearlings. The weights of mares can change at different times of the year depending on the amount of milk they need to produce, and the oldest horses in a band almost always drop weight. So get a sense of what the non-lactating members look like and factor their condition into your observations.

Next, look around the area where the band tends to graze. In the high desert, grass tends to grow where organic material is present, so you may find grass tucked up next to sagebrush. See if the overall presence of grass appears to be consistent. See if you can detect slight differences in the grasses. Oftentimes multiple varieties of grasses will be clustered together. Different varieties have slightly different shapes or seeds and mature at different times. If the grass you see doesn't all appear to be the same color, size, shape or age, then you're likely looking at a variety of different grasses - a healthy sign.