Diarrhoea is commonly seen in foals. Good hygiene practices and supportive electrolyte replacing supplements can aid hydration and recovery.
Diarrhoea in foals can be either harmless or fatal. It is essential to be able to decide when a foal has a normal foal heat scour or if the foal needs urgent veterinary attention. Often the severity of the diarrhoea and the need for prompt treatment is dependent on the age of the foal. Younger foals are more susceptible to overwhelming problems than older foals.
The foal heat diarrhoea is commonly seen in foals from 4–14 days old. Foals often develop mild, self-limiting diarrhoea. During this time, the dam is usually in season for the first time after foaling, hence the name “foal heat diarrhoea.” However, diarrhoea can also occur at this time in orphan foals; therefore, hormonal activity in the mare is unlikely to be involved in the pathogenesis. Although the cause is unknown, it may be associated with alterations in the foal’s intestinal microbial flora or alteration in diet as the foal begins to eat small amounts of hay and grain. The foal remains active and alert and has a normal appetite. Vital signs remain normal. Faeces are semi-formed to watery and not particularly smelly. Monitoring is important to ensure the foal’s condition does not deteriorate. Specific veterinary treatment is usually not necessary. Application of a protectant to the skin around the perineum helps prevent scalding of the buttocks.
Bacterial diarrhoea in foals can be can be a component of neonatal septicaemia, and diarrhoea can be seen with bacteraemia of any cause. Organisms that may be involved in neonatal bacteraemia and subsequent diarrhoea in neonatal foals include Salmonella spp, Escherichia coli, Klebsiella spp, and Clostridium spp. In younger foals bacterial diarrhoea is often due to Salmonella or Clostridia. The clostridial types that cause diarrhoea in foals work by producing aggressive toxins in the intestine. These toxins spread to the rest of the body. These foals are very sick and may die even with aggressive treatment. Rhodococcus equi while primarily a respiratory disease it may also cause diarrhoea in foals. Depending on the bacteria involved, the extent of the infection and the age and immune status of the foal these cases may be fatal.
In these cases veterinary intervention is essential as intensive antimicrobial treatment, correction of fluid loss and electrolyte abnormalities, and nursing care are needed. This can occur from time of birth. In very young foals it is important to ensure adequate passive transfer of colostral antibodies has occurred. While some foals may be treated successfully at home they may need to be moved to a veterinary hospital for intensive round the clock care.
Rotavirus is the main cause of viral diarrhoea in foals; however, other viruses have been implicated. Foals with rotavirus diarrhoea are usually very sick and depressed and are not nursing. They have profuse, watery and very smelly diarrhoea. It is usually seen in foals that are less than 2 months old; younger foals typically have more severe clinical signs. The diarrhoea usually lasts up to seven days although it can persist for several weeks. The virus affects foals by killing some of the cells lining the intestine and causing malabsorption problems. Treatment is generally supportive and involves giving intravenous fluids to prevent dehydration. Sick foals are highly contagious and should be isolated in the stall in the barn in which the foal originally became ill or moved to a designated isolation facility. In some studs the policy is to vaccinate against rotavirus. The vaccination is administered to the pregnant mare during the 8th, 9th and 10th month of each pregnancy.
It is pertinent in all cases of foal diarrhoea to ensure excellent standards of hygiene. Isolation is recommended. Nominate who is responsible for the foal and reduce all unnecessary foot traffic. Anybody coming into contact with foals with diarrhoea should wear disposable gloves and washable boots. It is best to have a disinfectant footbath outside the stable door. When the foal is back to full health and can rejoin the herd disinfect the stable thoroughly with an appropriate disinfectant.
Nutritional diarrhoea can result from overfeeding and improper nutrition. This can happen if a foal is reunited with the mare after a period of separation, and with very greedy foals. If feeding orphan foals, it is important to use an appropriate milk replacer or goat’s milk if replacer is not available. Do not use cow’s milk. Lactose intolerance in foals is rare. Diarrhoea can also develop when foals consume indigestible substances such as roughage, sand, dirt, and rocks. Diarrhoea in foals has also been reported to be associated with parasites, infection by Strongyloides westeri, Parascaris equorum, and Cryptosporidium spp. Be aware of pasture rotation and have a well structured worming regimen.
Prevention is better than cure. Try to keep foaling area as clean as possible. Isolate any foals with concerns. Monitor all foals very carefully. When foals are sick they can seem fine and then deteriorate very quickly. When in doubt watch how much the foal is drinking and take a temperature, if you are worried it is best to contact your veterinary surgeon. If there are early signs of diarrhoea but the foal is still nursing, wash any signs of diarrhoea off and apply a protectant on the skin around the perineum and down the foals hind legs. This serves two functions: you can easily see if the diarrhoea is getting worse and the foal is less likely to have bald patches due to diarrhoea burning the hair.
Diarrhoea is a common condition of young foals. Most cases are mild and self-limiting such as; foal heat scour but infectious viral or bacterial diarrhoea can cause severe illness.
All cases of diarrhoea result in increased fluid and electrolyte loss from the body.
Replacement of these lost fluids and electrolytes is essential in order to prevent dehydration of the foal. In mild cases where the foal is lively and on suck, continued milk and water intake will replace lost fluids. An oral electrolyte replacement treatment helps maintain fluid balance. Attasorb gel and Kaosorb are specially formulated oral electrolyte replacement supplements which are easily administered and absorbed by foals with diarrhoea to support their fluid and electrolyte balance.
A foal with severe diarrhoea, that is not drinking or, has an elevated temperature should be examined by a veterinary surgeon.