They are used in many aspects on the ranch, and a sick horse can set a rancher back weeks or months. Keeping horses healthy is very important to their longevity on the ranch.
There are many diseases horses can get, but there are a few ranchers should be concerned about. “Ranchers should be most concerned about West Nile virus, as well as eastern and western equine encephalomyelitis.
Rabies poses a risk to all horses,” says Dr. Terry Hensley, an assistant agency director at Texas A&M Veterinary Medical Diagnostic Laboratory and a Texas A&M AgriLife Extension veterinarian.
He continues, “Ranchers may also be concerned about rhinopneumonitis, influenza, strangles and pigeon fever. Management practices on the ranch, age of the horses and travel to events can influence the risk of exposure to these diseases and need for vaccination.”
A strong vaccination program is very important. “All horses, regardless of how they are used or where they are located, should receive the core vaccines as defined by the American Association of Equine Practitioners (AAEP).
These core vaccines are WNV, EEE, WEE, rabies and tetanus. Depending on the use of the horse, age, herd history, etc., other vaccines may need to be added such as strangles, rhino, flu, etc.,” he says.
According to the AAEP, “Core vaccines are defined as those that protect animals from diseases that are endemic to a region or have potential public health significance, are required by law, protect against virulent and highly infectious organisms, and/or those posing a risk of severe disease.
Core vaccines have clearly demonstrated efficacy and safety and thus exhibit a high enough level of patient benefit and low enough level of risk to justify their use in the majority of patients.”
Hensley suggests a vaccination program should be developed for each ranch based on their needs. “The vaccination program should be designed with the assistance of a veterinarian who is familiar with the individual ranch.
Presence of breeding mares/foals, young horses, travel, etc., must be taken into consideration, and this is where consultation with a veterinarian is important in developing a vaccination program. There is no one-size-fits-all horse vaccination/herd health program,” he explains.
According to the AAEP, “Veterinarians provide the foundation for realistic client expectations with respect to vaccination and should help their clients understand that no vaccine is 100 percent effective in preventing disease, vaccination without good management will not prevent infectious disease, horses within a population vary in degree and duration of protective response after vaccination, and protection is not immediate and requires the appropriate number of immunizations administered at appropriate intervals (prior to significant exposure).”
If the ranch does raise horses and has pregnant mares and foals, vaccinating the mares is very important to foal health. “It is important to vaccinate broodmares four to six weeks before foaling for their own protection, as well as to maximize concentrations of immunoglobulins in their colostrum to be passively transferred to their foals.
The majority of vaccines administered to broodmares during late gestation to maximize immunoglobulin transfer via the colostrum do not carry a ‘safe for use in pregnant mare’ claim. However, this is an accepted practice, and clinical experience indicates these products are safe for this purpose,” according to the AAEP.
Deworming is also a vital part to keeping horses healthy. “Ranchers should be most concerned with the following parasites: Adult horses – small strongyles and bots are the primary concern. Young horses – ascarids are biggest concern.
Tapeworms can be a secondary concern on some premises. You also may see summer sores on particular horses, and these are caused by Habronema. Some horses may exhibit skin lesions due to Onchocerca,” says Hensley.
Having a deworming program can help ranchers to avoid these parasites. “As with vaccination programs, a veterinarian familiar with the ranch and the horse management should be consulted when designing a deworming program.
In most instances, adult ranch horses should be dewormed at least twice yearly, once during peak transmission focused on small strongyles and once after first frost for bots and encysted strongyles.
Moxidectin or ivermectin may be best choice at the fall/winter deworming. Again, there is no one-size-fits-all deworming program. The ranch should work with a veterinarian to develop a program tailored to the specific needs of the ranch,” he explains.
Biosecurity measures
Once vaccines and deworming plans are developed, biosecurity measures should also be taken. Biosecurity is important to not only the horses on a ranch but also to the cattle.
Tensley suggests a few things that should be taken into consideration for biosecurity. “You need to minimize hauling outside horses onto the ranch. If day-work cowboys are used and they bring their own horses, make sure their horses’ vaccinations are current.
Some horses can be carriers of certain diseases. They show no outward clinical signs but can be a source of infection for other horses. Keep any horses that exhibit respiratory signs separate from other horses on the ranch,” he says.
Other contingencies
However, even with good biosecurity, vaccination and deworming programs, disease outbreak can occur. In the event of an outbreak, ranchers should know what their plan of action is before the outbreak occurs.
“Some simple management practices can be put into play. These should include isolation of sick horses and, if possible, isolation of known exposed horses. Stop movement of horses on to or off of the ranch.
Care for the sick horses last. Make sure ranch workers always care for the healthy horses first and then the exposed horses, leaving the sick horses for last. If manpower is available, assign someone to care only for the sick horses. Use good hygiene such as hand-washing and washing boots as well,” Tensley says.
He adds, “Your veterinarian is a valuable resource in designing a biosecurity program for your ranch and horse herd. It is advantageous to have a biosecurity plan in place before a disease event happens.”
Many ranchers take their horses off of the ranch for different events such as branding for a neighbor, moving cattle, rodeos and roping events. In the event of taking a ranch horse off of the ranch, there are a few things ranchers should be aware of and do to protect their horses.
“If ranch horses are carried to outside events such as rodeos and ropings, be sure to carry your own feed and water buckets. Do not water at the communal water trough, and this includes dipping water out of the trough with your bucket.
Fill the buckets from a water tap. If possible, avoid nose-to-nose contact with other horses and tie your horses to your own trailer if possible between competitions,” Hensley suggests.
Returning home
Once horses come home from events, there are also precautions that should be followed. “Horses that return to the ranch from events should be isolated from the other horses, especially young horses, for at least seven to 10 days if at all possible,” he says.
If a rancher takes his horses off the ranch, additional vaccines should also be considered. “Horses that go off of the ranch to events should be vaccinated for rhinopneumonitis and influenza.
The pros and cons of using the strangles vaccine for these horses should be discussed with a veterinarian,” Hensley states.
Keeping ranch horses free from disease and parasites is pretty simple and can help a rancher make sure his or her horse is always ready to go. The cost and time involved in vaccinating, deworming and having an effective biosecurity program far outweigh the costs. 
Robyn Scherer is a freelance writer based in Colorado.
