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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.

Omeprazole and Its Impact on Mineral Absorption in Horses

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.

The Key to Ulcer Prevention

Here at FeedXL, we always say that if your horse has ulcers then you must treat with an acidity reducing medication like omeprazole. However, the keys to long-term prevention of ulcers in our horses are 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. 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.

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

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Joint Supplements: Are They Beneficial?

Joint supplements! A lot of you use them, and while there is theoretical justification for their use there is still very little science that actual shows a proven benefit in feeding them.

A study just published does however lend some nice information in this area. It is both blinded (i.e. the people feeding the horses, the people assessing the horses for various measures of movement and levels of comfort don’t know if the horses was on the joint treatment or not at the time of assessment so it couldn’t influence what they ‘saw’ and recorded. And the author who analyzed the data was blind to which horse was on what treatment so they too could not be influenced) and is also a crossover study where each horse in the study was on both the joint treatment and the placebo and assessed on both so you could see changes in the same horse as opposed to changes between two different groups of horses where one group is treated and one group given a placebo.
This study also used ‘objective’ measurements of gait using high speed motion capture to assess movement of the hind legs at the trot.

The results are interesting, with significant improvements in lameness scores (less lameness in treated horses), less response to flexion tests and improvements in muscle tone reported (plus many other results).

The full paper is available here for full download for the next week or so (https://www.sciencedirect.com/…/article/pii/S0737080616304749) for those of you interested in reading it.

A good time to remember too that not all joint supplements are created equally as far as the ingredients and amount of ingredient per dose they contain. The supplement used in this study was ‘FlexAbility’, from Science Supplements, UK; it contains chondroitin sulfate 162 g/kg, glucosamine 190 g/kg, vitamin C 80 g/kg, methyl sulfonyl methane 256 g/kg, docosahexaenoic acid 66 g/kg, eicosapentaenoic acid 34 g/kg For those of you who use FeedXL, if you look in the ‘Health’ tab in your results you will see a breadown there of the various joint nutrients and how much of each are in your horse’s diet when you use a joint supplement.

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Feeding for Sound Bones

When breeding a young horse, one of the highest priorities, regardless of what the horse is being bred for, is to have the foal develop with strong bones and ‘clean’ legs, free from developmental disease and defects like osteochondritis dissecans (OCD). Developmental orthopaedic diseases (DODs) are known to be what is called ‘multifactoral’, or caused by multiple things. One of the best known and also easiest to manipulate causes is nutrition.

Unfortunately DOD and the role nutrition plays is not well understood in much of the breeding community. It is well known that overfeeding is a cause but unfortunately many a breeder’s answer to that is to not feed nearly enough and in doing so unwittingly causing problems through other mechanisms like mineral deficiencies. So how do you feed young horses for sound bones? Let us take a look…

CONTROL GROWTH RATE

The one very predictable way to increase a horse’s risk of developmental bone diseases including OCD is to feed too much and make youngsters grow too fast. In this situation the young horse’s bones grow too quickly to be properly mineralised, or problems like contracted tendons and being over at the knees develop and put uneven pressure on growing bones and joints.

To minimise the risk of rapid growth rates causing problems with bone development, feeding regimes need to be closely controlled and adjusted as needed to match changing pasture and climate conditions and an individual horse’s requirements. Growth rates should be closely monitored through regular weighing where possible. The people responsible for feeding should also be observant, experienced and diligent, checking for signs of overfeeding and rapid rates of growth including excess body condition, physitis or any deviation in leg structure from normal in one or more of the horses in a group on a daily basis. As soon as any signs of overfeeding are noticed, feed regimes should be adjusted immediately to bring growth rates back in check.

In keeping growth rates in check however you also need to be really careful that you don’t hold youngsters back too much for fear of DOD. Horses that are stunted from an early age by overzealous control of their growth rates may never actually reach their full potential for growth at a later age … it is all a balancing act.

MIND YOUR MINERALS

It is also well recognised that unbalanced mineral nutrition can lead to developmental issues in growing thoroughbreds. While a growing horse requires an extensive suite of minerals, minerals of particular importance for bone development are calcium, phosphorus, magnesium, copper, zinc and manganese. Not only do these minerals need to be supplied in the diet at correct levels, but they also need to be provided in the right ratios so that one mineral doesn’t block the absorption of the other (for example too much phosphorus will block the absorption of calcium, too much zinc will block the absorption of copper and too much potassium will block the absorption of magnesium).

Balancing the mineral component of growing horse rations is not a super simple task, but this is where FeedXL comes into play. FeedXL allows you to see if these mineral requirements are being met in a young horse’s diet and also if they are in the correct ratios to one another.

FeedXL also allows you to constantly adjust diets as a youngster’s growth rate changes allowing you to control growth rate (by increasing or decreasing feed amounts) without ever compromising mineral intakes.

ARE THERE PROBLEMS LURKING IN YOUR PASTURE?

Because so much of a young horse’s sound development is dependent on mineral intake it is important to have your pasture (or hay) tested to assess its mineral status throughout the year. Pastures can have various characteristics that can quite quickly unbalance a diet and bring your entire feeding regime unstuck. Some examples from pastures that I have looked at in the past 12 months include:

  • Unbalanced calcium to phosphorus ratio – Pastures that contain more phosphorus than calcium are more common than you would imagine and if not corrected by careful calcium supplementation can lead to a long term calcium deficiency which will almost certainly disrupt sound bone development.
  • Unbalanced zinc to copper ratio – Pastures that contain more than 5 parts zinc to 1 part copper put horses at risk of a copper deficiency. While not common, it is critical that this ratio is corrected through calculated supplementation to avoid copper deficiency.
  • Extreme potassium content – Potassium contents upwards of 55 grams per kilogram of pasture dry matter have recently been recorded in horse pastures. While very little work has been done on the impact of this in horses, it is well recognised that potassium at these levels will disrupt the absorption and metabolism of both magnesium and calcium in other animal species and circumstantial evidence suggests this may be the case in horses.
  • Mineral deficiencies – this is perhaps the most common problem seen in pastures. Calcium, copper and zinc are the three most common deficiencies seen of minerals important to bone development. Phosphorus and very occasionally manganese can also be too low to meet a growing horse’s requirements. Luckily this problem is also the easiest to correct through calculated supplementation with good quality feeds or pasture balancer pellets.

Because of all the spanners that pasture can throw into your feeding regime the first step toward putting together a well balanced feeding regime for growing horses should always be pasture analysis. Here at FeedXL we recommend you use Equi-Analytical (https://www.equi-analytical.com/) for your pasture analysis needs.

PROVIDE GOOD BUILDING BLOCKS

Bone is built upon protein, both collagen and non-collagenous proteins, so it is reasonable to assume that the protein quality of the diet will have an impact on the quality and soundness of bone in growing horses. Diets based on high quality protein will better support sound bone development than rations based on low quality sources of protein like cottonseed meal.

WHAT ABOUT FANCY STUFF?

There are many supplements and feed additives on the market nowadays that will claim they can help reduce OCD and other bone issues. Some are backed by credible science, others aren’t. The key to using any of these supplements though, if you wish to give them a try, is to make sure you are feeding them with a well balanced diet, as no matter how good they are or claim to be, using them when other problems already exist in the diet is not going to give you better results. For example adding silica to diets that are deficient in copper is not going to solve any problems that may exist due to the copper deficiency.

THERE IS STILL A LOT WE DON’T KNOW…

While managing growth rates, feeding well balanced diets that are formulated to suit pasture conditions, meeting all mineral requirements and feeding diets with high quality protein will give you the very best chance of producing a sound yearling, some horses will still develop bone issues, even under the very best conditions. It is also well recognised that some mares will consistently throw foals that go on to develop OCD or other issues. What we still don’t know is why, what is genetically different about these animals that puts them at much higher risk?

There is however a lot we do know and with some good management and the use of tools like pasture testing and FeedXL you can dramatically reduce the risk of developmental orthopaedic diseases in your growing horses to produce sound, athletic horses for any equestrian discipline.

 

Dr. Nerida Richards is FeedXL’s resident equine nutrition specialist. With a degree in Rural Science, a doctorate degree in equine nutrition and nearly 20 years of full time, on the ground experience in feeding all types of horses Nerida is able to help FeedXL members solve any problem they may come up against with feeding their horses. To learn more about Nerida and to ‘meet’ the rest of the FeedXL team, check out our About Us page here.

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