Horses fed oaten hay are almost three times more likely to develop tooth decay according to a new study at The University of Western Australia.
Dr Kirsten Jackson, an equine dental veterinarian who is also studying a Masters of Philosophy by Research at UWA, said tooth decay in horses, or equine peripheral caries, is very common in Western Australia and causes a great deal of pain in horses.
The study, published this week in Equine Veterinary Journal, surveyed 500 horses in WA and looked into risk factors for the condition to try to find a reason for why it was so common.
"We found tooth decay affected nearly 60 per cent of horses surveyed and one of the most significant risk factors was the hay source fed to the horse," Dr Jackson said.
"The horses fed on meadow hay were less than half as likely to have peripheral caries. We believe that the high water-soluble carbohydrate ('sugar') levels in the cereal hays are likely to be a factor."
The study found the water source offered to the horse was another risk factor with horses on bore or groundwater least likely to have peripheral caries, followed by those on scheme or drinking water, then rain water while those on dam water were the most likely to have tooth decay.
The length of access the horse had to pasture was also significant, with horses that had access to significant pasture for eight to twelve months of the year less likely to have decay compared to those on minimal or no access to pasture.
Thoroughbred horses were also more likely to have peripheral caries than western breed horses- such as quarter horses and stock horses; or warmbloods – a subset of sport horse breeds used for competition in dressage and show jumping.
"Before this research we had no idea what was causing the condition; we would just watch horse's mouths deteriorate and not be able to do anything about it," she said. "We can now give practical, evidence-based advice on management and we have seen the condition reversed and resolved in dozens of cases now.
"By changing the way we manage tooth decay and avoiding feeds that are known to increase the risk, we can treat those with the condition and also prevent other horses from developing it in many cases.
"The exciting part about the research is that the decay only affects that part of the tooth in the mouth at the time and the horse's teeth continue to erupt throughout their lifetime.
"With the knowledge gained from the research, we have been able to modify the diet of affected horses and stop the process of decay. This allows the healthy tooth to erupt down and as such, we have been able to resolve the condition in many cases."
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K. Jackson et al. Equine Peripheral Dental Caries: An epidemiological survey assessing the prevalence and possible risk factors in Western Australian Horses, Equine Veterinary Journal (2017). DOI: 10.1111/evj.12718