Do ulcer medications affect skeletal health in horses?

Gastric ulcers are an all too common problem facing our horses. While feeding and general management play a huge role in squamous ulcer (ulcers found in the upper part of the stomach) treatment and ongoing prevention, medications that reduce acidity in the stomach to create a more favourable environment for ulcer healing are certainly an essential part of the treatment and also ongoing prevention of ulcers.

However, with gastric acidity being needed to facilitate the absorption of minerals like calcium, and documented studies in humans linking the use of medications like omeprazole that reduce gastric acidity with increased bone fracture, there has always been this nagging question of whether using omeprazole in horses would have a negative impact on bone health.

Dr Brian Nielsen, Professor in Equine Exercise Physiology, Michigan State University, presented the results of his study ‘Omeprazole and its impact on mineral absorption in horses’ to the Recent Advances in Animal Nutrition – Australia conference last week.

Dr Nielsen reported that when given at the preventative dose of 1 mg/kg of bodyweight for a period of 8 weeks, omeprazole caused no significant treatment effect on radiographic bone aluminium equivalence (meaning bone density was not affected) and did not affect markers of bone formation. Nielsen et al (2017) concluded that ‘daily administration of omeprazole did not appear to have any negative effects on indices of skeletal health measured in the study’… so good news for those of you who have horses who need repeated rounds of omeprazole at the preventative dose rate to keep ulcers under control!

However, Dr Nielsen does warn that use of omeprazole for periods longer than 2 months, or at the recommended treatment dose (of 4 mg/kg of bodyweight) could still pose a risk to skeletal health in horses.

Here at FeedXL, we always say that if your horse has ulcers then you must treat with an acidity reducing medication like omeprazole. But, good management, regular, frequent feeding, feeding lots of forage, avoidance of long periods of time without feed, constant access to water, reducing stress in any way possible, and probably most importantly, always feeding forage before exercise (alfalfa/lucerne is best) so you never ever exercise a horse on an empty stomach are still key to the long-term prevention of ulcers in our horses.

Nielsen BD, Eckert SM, Robison CI, et al. Omeprazole and its impact on mineral absorption in horses. Animal Production Science 2017;57:2263-2269.

http://www.publish.csiro.au/AN/AN17323

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