Greystone Veterinary Services

Eastern Equine Encephalomyelitis (EEE): A report from the NCDA&CA Equine Disease Committe meeting on June 25, 2003 indicated that 4 cases of EEE have been confirmed so far this year, about a month ahead of the traditional "start of the season." It is felt this early start is probably due to the rains and bumper crop of mosquitoes. Please remember that:

It is a reportable disease to the NCDA&CA
It is important to confirm acute neurological disease, whether Rabies, EEE, or WNV. Where there is one case of EEE, there is the potential for other human and/or horse exposure
Proper initial vaccination is important - 2 does 3-6 weeks apart. Vaccination needs to be 6 months apart. Annually vaccinated horses may not be protected sufficiently towards the end of their vaccination interval.

Neonatal Isoerythrolysis (NI): A genetic condition affecting foals within the first week of life, where the mare generates an antibody response against the foal's red blood cells. The mare's antibodies enter the foal's circulation via colostrum ingestion. If the foal has the target antigen on its red cells, the antibodies attach to the red cells and cause their destruction.

Clinical signs of NI appear in the first 2 to 24 hours, but may occur as late as 7-8 days of age. They include weak, depressed, 'floppy' foals with evidence of tachycardia, tachypnea and pallor.

One way to prevent NI is to avoid incompatible matings and the other is to prevent the offending antibodies from entering the foal. This involves muzzling the foal until a colostrum titer shows a sufficiently low antibody level, usually 24-72 hours.

(Adapted from "Neonatal Isoerythrolysis" by Jill Johnson McClure in Current Therapy in Equine Medicine ed. N. Edward Robinson)

UC Davis Veterinary Medical Teaching Hospital now offers equine blood typing and antibody screens. Equine antibody screens should be performed on mares 2-3 weeks prior to foaling to detect anti-erythrocyte antibodies. This will establish if the foal is at risk of developing neonatal isoerythrolysis (NI). For more information, please call Joy at 530-752-1303.

Overo Lethal White Syndrome (OLWS) is a condition that occurs in newborn foals. The condition is genetic, and both parents carry the defective gene. Horses that carry this gene are most commonly overo white patterned horses (frame overos), but there are exceptions. OLWS foals have blue eyes and are completely or almost completely white at birth. These foals initially appear normal except for their unusual coloring. After a varying period of time, troubling signs of colic emerge due to the foal's inability to pass feces. The OLWS foal has an underdeveloped, contracted intestine caused by a failure of the embryonic cells that form nerves in the gastrointestinal system. Oddly enough, these cells also play a role in determining skin color. There is no treatment for OLWS, and surgery to bypass the intestinal damage has never been successful due to the extensive nature of this type of lesion. Veterinarians advise euthanasia for all OLWS foals because death will inevitably occur from colic caused by fatal constipation. See full article

West Nile Virus (WNV):On August 1, 2001, the USDA and Fort Dodge Animal Health announced approval of a conditional license for an inactivated vaccine against West Nile Viral Encephalitis (WNV) for use in horses. Also, keep in mind that it is important to confirm acute neurological disease, whether Rabies, EEE, or WNV. Where there is one case of WNV, there is the potential for other human and/or horse exposure.

Signs and symptoms of encephalitis in horses:

Ataxia, characterized by stumbling, staggering, or wobbly gait more often affecting the rear limbs
Weakness
Lying down with difficulty and inability to rise
Depression and listlessness
Facial paralysis or twitching
Teeth grinding
Blindess
Fever in 1/3 of affected horses

For the most current information on West Nile Virus and your horse, please check this webpage: http://www.aphis.usda.gov/vs/nahss/equine/wnv/.

Cold Weather Tips:

During cold weather, the horse requires additional energy to maintain its internal body temperature and keep warm. When temperatures drop below 45 degrees (critical temperature), significant amounts of energy are used by the horse to maintain its internal body heat.
Forages (hay), which are digested by microbes in the cecum and large intestine, produce more heat than concentrate mixes (grain). The best way to increase internal body heat while maintaining a consistent energy intake is to increase hay feeding. A 1000 pound mature horse should consume 15-17.5 pounds of hay daily to meet critical temperature needs during cold weather.
Maintaining ample water intake is the most critical part of ensuring the health of your horse during cold weather. Low water intake is directly related to the increased incidence of impaction colic. Water intake can be encouraged by increasing the amount of hay forage fed prior to a drop in temperature.

Adapted from the NCSU Cooperative Extension Service Newsletter

The latest Equine Protozoal Myeloencephalitis (EPM) update can be found in this bulletin from Michigan State.

Click here for quick guide to Equine Healthcare, prepared for a beginner's clinic on basic horse care.
Also available in Word format for download.

This is the Foaling Assessment form we use for each foal delivered at Greystone. We probably adapted it from some other source, so please feel free to use it for your babies if you find it helpful.

Our transported semen shipment data form is also available for download. It is in Excel format.