A “staggering” 98 percent of foals in a study developed gastric lesions within two weeks of weaning.
“This is the first study that has reported prevalence data for foals immediately after weaning despite a wealth of anecdotal evidence suggesting weaning as a risk factor for equine gastric ulcer syndrome,” Michael Hewetson and his colleagues wrote in the journal, Acta Veterinaria Scandinavica.
The high percentage of gastric lesions in weaned foals underscored the importance of gastric ulceration in this age group, they said.
The finding was reported in a study in which researchers found that a simple blood sucrose test may be useful in efforts to identify foals with stomach lesions.
Because blood sucrose levels relate not only to equine gastric ulcer syndrome, the test is unlikely to replace gastroscopy in diagnosing the problem. However, indications are it could be clinically useful in identifying foals that might benefit from gastroscopy, the researchers said.
Equine gastric ulcer syndrome, or EGUS, is an important cause of disease in foals, with a reported prevalence in scientific literature ranging from 22% to 57%.
Although it is most commonly seen in older weanling foals, ulcers have also been reported in foals as young as 24 hours.
While some foals show no outwards signs of ulcers, others can show ill thrift, a lack of appetite, excessive saliva production, teeth grinding and even colic. Some ulcers can even perforate, causing death.
“Considering the potentially fatal consequences of gastric ulceration in the foal and the fact that up to 57% of foals are asymptomatic, large scale screening on stud farms to ensure an early diagnosis and prompt treatment prior to the development of complications is desirable,” the authors said.
Currently, gastroscopy is considered the only reliable way to definitively diagnosis the problem in foals. However, it is unsuitable as a screening test because of the cost and time involved.
A sucrose permeability test represented a simple, economical alternative to gastroscopy for screening purposes, they said, noting that the diagnostic accuracy of a blood sucrose test in adult horses had previously been reported.
However, the same cannot be assumed for foals because there were fundamental changes in the gastric lining of the stomach that occur in the first six months of life that may alter permeability to sucrose.
The researchers described their research involving 45 weanling foals, all from one stud farm. None had been reported as showing any clinical signs suggestive of gastric lesions at the time of gastroscopy.
Each foal was subjected to gastroscopy and sucrose permeability testing twice – seven days before and 14 days after weaning.
“The prevalence of gastric lesions prior to weaning was 21% and increased to a staggering 98% within two weeks of weaning,” the study team reported.
Their results and analysis indicated that a blood sucrose permeability test was a useful screening test for detecting gastric ulcers in weanlings. The results of each test not only provided a good indication of whether lesions were likely to be present, but also whether they were in the upper (squamous) part of the stomach, the lower acid-secreting portion of the stomach, and whether they were clinically significant.
It fulfilled all major criteria for a screening test: it was economical; minimally invasive and acceptable to owners; was easy to perform; and accurate, with good sensitivity.
The authors noted that, despite the severity of disease seen in some foals, none had shown clinical signs at the time of testing.
This, they said, made the results of the study very relevant to the general population, where many foals with severe ulcers do not demonstrate clinical signs. “Therefore the benefit of a sensitive screening test cannot be underestimated.”
The full study team comprised Hewetson, Monica Venner, Jan Volquardsen, Ben William Sykes, Gayle Davina Hallowell, Ingrid Vervuert, Geoffrey Theodore Fosgate and Riitta-Mari Tulamo.
- Prior to weaning, the mares and foals had access to grass hay and water ad libitum; and were fed about 13kg per mare and foal per day of a total mixed ration comprising 3kg of corn silage, 6kg of grass silage, 2kg of oats, 0.5kg of straw, 0.3kg of soybean meal, and 50 grams of a commercial mineral vitamin supplement. After weaning, foals were separated from their dams, and were fed the same total mixed ration or alfalfa chaff in addition to ad libitum grass hay.
Diagnostic accuracy of blood sucrose as a screening test for equine gastric ulcer syndrome (EGUS) in weanling foals
Michael Hewetson, Monica Venner, Jan Volquardsen, Ben William Sykes, Gayle Davina Hallowell, Ingrid Vervuert, Geoffrey Theodore Fosgate and Riitta-Mari Tulamo
Acta Veterinaria Scandinavica 2018 60:24 https://doi.org/10.1186/s13028-018-0377-5