Horses are usually very healthy during the winter months as long as they have plenty of good hay and water. When the weather starts to warm up, disease problems become much more common. During the warm months, respiratory viruses such as Influenza and Rhinopneumonitis prevail. Often 2 to 3 big epidemics of Influenza occur in Western Colorado and Eastern Utah between March and November. Rhinopneumonitis is always around during these month also.
Longer, warmer days and green grass stimulate hormonal activity, so more injuries occur due to horses running into fences. Tetanus is always a concern whenever a full thickness laceration through the skin occurs. Mosquitoes transmit sleeping sickness or Encephalitis, so it is a concern during the warmer months also. Potomac Horse Fever is a disease that has been diagnosed in any of the connected states. Ticks are thought to be involved in transmitting the disease, so it is seen mostly in the warm months.
It is evident the optimum time to vaccinate is springtime so horses will have the highest possible immunity during the peak exposure period. Vaccines for all of the above mentioned diseases are available individually or in various combinations. If you vaccinate for Tetanus and Encephalitis in the springtime, the immunity should protect until the next springs. The respiratory virus vaccines such as Flu and Rhino, may need to be boosted a few times in a year to maintain a strong enough immunity to withstand the challenge of an epidemic. Traveling or show horses should be revaccinated for Flu and Rhino at 2 month intervals. If mares are vaccinated 1 to 2 months before foaling, the foal receives protective antibodies when he first nurses the mare and gets the colostrum. Potomac Horse Fever has not been diagnosed in Western Colorado. However, Colorado State University surveyed the state and found 16% of Colorado horses had antibodies against the causative organisms. Most people choose not to use Potomas Horse Fever vaccine, but it is available.
Deworming should be done regularly year round, not just in the springtime. Spring is an excellent time to deworm for stomach bots since some bots mature in the stomach later than others and a winter time deworming may not have killed all of them. Special attention should be paid to Strogyle or Bloodworm control in the spring, since Bloodworms multiply rapidly when the green grass starts to appear. A horse, which has not been dewormed, can pass up to 25 million Bloodworm eggs per day. Invermectin (Eqvalan or Zimectin) is excellent for Bot and Bloodworm control. Deworming by passing a stomach tube and using a combination of dewormers is also a good method of worm control.
Ticks and lice are often seen on horses in springtime. Ivermectin is helpful in some cases where bloodsucking parasites are involved. In the case of biting parasites, topical insecticides are necessary. Care must be used to select an insecticide that is safe for use on horses.
Dental problems do not just occur in springtime, but most horses are going into their season of heavy usage. Correction of small problems such as filing sharp points on the inside edge of the upper molars can mean the difference between a successful season or one of head throwing, bit chewing, and fighting. Some dental problems can prevent the horse from maintaining his optimum body weight and condition. Horses with malocclusions of incisors or broken off incisors may not be able to maintain body weight on pasture. They will often require supplemental feeding, such as additional hay or cubed feed.
Colic is a year round problem, but seems to be more common in springtime. This may be due to a variety of reasons, including foaling, weather changes, green grass and weeds being available for feed, depletion of sources of good quality hay, and increased incidences of internal parasites. Prevention includes selecting quality hay, feeding small amounts several times a day, rather than large amounts twice daily, and regular deworming. In broodmares, the amount of hay should be reduced and grain increased to reduce bulk in the large intestines during the final 2 weeks prior to foaling.
Horses are expensive animals to buy and maintain. The time and money spend on prevention often can eliminate disease or death loss, which can be economically and emotionally devastating.
We would like to take this opportunity to thank HARRIS VETERINARY CLINIC, in Grand Junction, Colorado for providing us with this information.
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