At the American Association of Equine Practitioners Focus on Colic Meeting, held July 24-26 in Indianapolis, Ind., Fairfield T. Bain, DVM, MBA, Dipl. ACVIM, ACVP, ACVECC, an internist at Equine Sports Medicine & Surgery in Weatherford, Texas, discussed several methods by which to medically manage colic in foals.
A veterinarian should first perform a physical examination of a colicky foal to determine the severity of the problem.
“Perhaps the most important issue in approaching the foal with colic is to determine the specific cause and whether the problem is or has the potential to require surgical treatment for correction,” Bain began, noting the advancements in imaging and endoscospy that have aided the ease of monitoring a colicky foal.
“Today we are able to accurately identify alteration in content and structure of abdominal organs of the foal rapidly and easily using ultrasound and monitor the condition over time,” he said. “Abdominal radiography is occasionally useful in evaluating the contents of the foal’s abdominal cavity.
“Endoscopy also has its place in the evaluation of abdominal pain in the foal, from gastroscopy in the patient suspected in having gastric ulcer disease to rectal endoscopy for assessment of suspected atresia coli (lack of a segment of intestine),” he added.
“Following on the information presented in the initial evaluation and the ultrasound examination of the foal, we will create an outline approach to medical interventions including pain control, fluid therapy, intestinal motility management, and nutritional support.”
Bain explained that in most cases, the first step in medically managing the colicky foal is to provide pain management.
“Flunixin meglumine (Banamine) is commonly used as a first line medication to control mild to moderate abdominal pain,” he continued. “More severe pain may require medications such as alpha-2 agonists (e.g., xylazine) to control pain and prevent secondary injury to the foal.”
He added that in some cases opiate drugs can be used alone or in combination with another analgesic to provide relief.
Bain explained that in specific cases, different types of pain control can be employed. Pain caused by colonic gas distension related to a meconium impaction, pain caused by colonic fluid distension related to the onset of rotavirus infections, and pain caused by colonic cramping have all been noted to respond well to certain analgesics. Further, pain caused by gastric distension associated with intestinal reflux can be relieved by passing a nasogastric tube to allow the reflux to exit the stomach.
Bain stressed it’s important for horse owners to seek veterinary care for foals in pain, as a veterinarian will be able to select the ideal pain management option for each individual situation.
Bain continued to explain that fluid therapy and electrolytes are often needed to help the colicky foal’s cardiovascular system recover from fluid loss and inadequate fluid intake.
“Usually, the best first choice is a balanced electrolyte crystalloid solution,” he said. “An initial loading (dose) of 10 to 20 milliliters per kilogram (of body weight) may be given to correct dehydration or poor perfusion. Maintenance fluid requirements should then be considered as well as ongoing losses from gastric reflux or diarrhea fluid.”
In some cases, he said, veterinarians will add glucose to the fluids as an additional energy source for the foals. He noted, though, that the foal should be closely monitored for hypernatremia (or an elevated sodium level in the bloodstream) caused by “increased free water loss in the urine with varying degrees of hyperglycemia (an elevated level of blood glucose).”
“The duration of fluid therapy for the colicky foal will be determined by the type of lesion and the progression of the medical condition,” Bain added. “Some dehydrated foals with mild to moderate abdominal pain may respond to initial rehydration with no additional fluid requirements, whereas those with colic associated with enteritis or a surgical lesion could require more prolonged intravenous fluid therapy, especially if prolonged ileus (the intestine’s inability to function properly) is a component of the disease process.”
Bain also relayed that some colicky foals could benefit from receiving colloids (particles that remain within the blood vessel space to maintain fluid within the vessel) to support certain conditions that negatively affect the foal’s intestines. Foals with Lawsonia intracellularis infections often benefit from colloid therapy because of massive protein loss from the vessel space that occurs with this condition, he said.
Additionally, he noted that plasma administration can benefit foals with colicky conditions including:
- Failure of passive transfer of colostral antibodies; and
- Enteritis with infections such as Clostridium perfringens or C. Difficile.
Intestinal Motility Management
Bain explained that some colicky foals will benefit from prokinetic drugs, which are designed to encourage movement in the gastrointestinal tract.
“Improvement of gastric emptying and small intestinal motility may be helpful in improving the outcomes for foals affected with enteritis or gastroduodenal ulcer disease,” he said, noting that the most common prokinetics used in his practice include bethanecol, metoclopramide, and neostigmine.
“In theory, the use of a prokinetic in the presence of a physical obstruction–an example being a duodenal stricture–would be contraindicated, because it would potentially cause pushing against an impassable point and result in increased pain,” he noted.
Finally, Bain discussed the role of nutritional management in some cases of foal colic.
“In some foals, simple restriction of suckling to short periods of time may be useful, especially when there is some component of delayed gastric emptying involved, such as the foal with enteritis, ileus, or duodenal stricture,” he explained.
Further, he added, foals that have lost high levels of plasma protein could benefit from a high-nitrogen supplement, which could help maintain a proper plasma concentration and body weight in affected foals.
“Monitoring and adjustment of nutritional intake may be required as diarrhea can result from increased intestinal luminal osmotic load that results from the use of these high nitrogen products,” Bain noted.
Although some conditions that cause colic in foals and young horses will need to be corrected surgically, there are several means by which to correct other problems medically. Working closely with a veterinarian will ensure a foal receives the proper treatment for the type of colic he has.