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New Developments in Bone Mineralisation

Recent studies at leading equine nutrition research company, Kentucky Equine Research (KER), are proving something to be excited about.  These compelling research developments could reap benefits for both breeding/growing horses and racehorses in training, with a significant impact on bone density and bone health, and gastric health.

The research involves the areas of calcium absorption, bone mineralization and acid buffering in the gastrointestinal tract and will have significant applications for two main groups of horses; firstly, mares and foals, where the process of sound growth and development begins, and secondly, young horses in pre-training and racing, where the effects of soundness come to the forefront with occurrences of shin soreness, bone fatigue and micro-fractures.  The secondary benefit, showing a pH buffering effect in both the stomach and hindgut, has important implications for improved gastrointestinal health in all types of horses, particularly those on high grain diets.

In a breeding environment, all growing horses require energy, protein (amino acids), vitamins and minerals.   With the main aim of breeding performance horses being to produce sound athletes, the most critical minerals for growth of young horses are the macrominerals, calcium and phosphorus, and the microminerals, copper and zinc.  One of the biggest challenges in producing such horses, is the risk of wastages due to developmental orthopedic disease (DOD), a term which covers growth disturbances resulting from abnormal bone development, such as physitis and osteochondritis dissecans (OCD).  Researchers have identified that horses with lower bone mineral density have an association with more severe OCD scores, possibly related to the link between bone tissue strength and bone density (Firth et al, 1999). Whilst DOD is considered multifactorial, nutrition imbalances are one potential factor that can be identified.  A more bioavailable source of these nutrients critical to bone building is, therefore, a significant advantage.  Interestingly, when looking at the passage of transfer of minerals from mare to foal, milk is the main source of calcium and phosphorus during early life, whilst minerals such as copper and zinc are actually passed on during pregnancy, being stored in the liver of the foetus in the final months of gestation, hence the saying ‘don’t wait until the foal is born to being supplementing’. 

Concurrently, skeletal issues in young growing horses and racing horses are major performance, welfare and ethical issues around the globe.  Researchers associate bone density as a key indicator of bone strength.  Low bone density is associated with a higher incidence of skeletal problems such as fractures, shin soreness, OCD, and sesamoid issues (Neilson et al., 1997; Kobayashi et al, 2007).  This is of particular significance in young horses, which at birth, have a bone density of about 17%.  This increases to about 74% at 1 year of age.  Furthermore, bone is continually remodelling and adapting to periods of exercise and rest until horses reach skeletal maturity at the age of 5-6 years.  During this period, racehorses are put through the rigors of sale preparation, education, training and racing to begin their careers, therefore increased bone strength is pivotal in minimizing the risk of skeletal problems, with the most common being the debilitating condition, Equine Dorsal Metacarpal Disease, also known as shin-soreness.

Calcium makes up about 35% of bone structure, with approximately 99% of the calcium in the body found in the bones and teeth. With this in mind, KER researchers wanted to test the bioavailability of various calcium sources.  They compared traditional sources of calcium, such as limestone, with a marine derived source, Buffered Mineral Complex (BMC), and found that BMC had significantly higher digestibility.    

Buffered Mineral Complex (BMC) has a unique honeycomb structure, with a high surface area to volume ratio, which contributes to the high bioavailability and effective buffering properties for gastric and hindgut pH.  Along with this organic calcium source, bioavailable sources of organic copper, manganese and zinc are included to ensure high digestibility of other bone building nutrients. 

To test the efficacy of this blend for improving bone density in Thoroughbred racehorses in active training, KER researchers conducted a research trial in thirteen 2 & 3 yr old horses in training in Florida, for a period of 90 days.  Horses consisted of 2 & 3 year-olds that were beginning race training, three-year-olds in active race training, and older horses returning to training after a 60- to 90-day break from active training.  Horses were fed Timothy hay and a fortified concentrate at levels required to maintain body weight throughout the study. The base diet supplied 64 g Ca and 42 g P/d. Seven horses received 120 g/d of Triacton which supplied an additional 15 g Ca and 3g P, and 7 horses received 120 g/day of a placebo pellet.  The supplement contained calcium, phosphorus, magnesium, silicon, boron, copper, zinc, manganese and Vitamins A, D, K and C. The horses were paired by age and exercise intensity and then randomly assigned to treatments. One horse from the placebo group was removed from the study because of lameness unrelated to bone development and has not been included in study results. There was no difference in average age between the two groups. Training consisted of slow and fast work. The average total distance trained by the horses at different gaits in each treatment group was measured using KER ClockIt and there was no difference in training intensity or duration between the two treatment groups (Pagan et al, 2018).

Radiographs of the left front cannon bone from dorsal-palmar and lateral-medial views were taken at 0, 30, 60, and 90 days of the study. An aluminum step-wedge was placed in plane with the cannon bone to use as an external measure of bone density. The density of the lateral, medial, dorsal, and palmar cortexes of the cannon bone were measured.

The study showed that the horses fed Triacton had a significant increase in both dorsal cortical and palmar cortical bone density compared to the placebo group, which was unchanged in 90 days.  The results were pivotal, and confirmed the hypothesis that the increased bioavailability of these key bone-building minerals sources when combined with important vitamins, would have a significant impact on the quality of bone and bone formation, as demonstrated through a significantly increased bone density and a trend to increased bone thickness and width.  As bone density is a key indicator of bone strength, researchers concluded that supplementation with Triacton resulted in stronger bones. 

This bone building supplement will be a great tool for breeding farms, suiting horses right through from mares in foal, to foals, weanlings and yearlings.  These developments will also benefit horses spelling on farm, as we know that bone density decreases during rest periods (Kobayashi et al, 2007), and also those beginning pre-training, where bone remodelling is occurring in order to adapt from rest to exercise.

Further studies at KER showed the BMC also served as a potent buffer in the gastrointestinal tract.  Reducing acid load in both gastric and hindgut regions of the digestive tract is important to maintain health. Whilst traditional limestone (calcium carbonate), commonly used as a source of calcium in feeds, has some ability to buffer acid, BMC has been shown to provide greater buffering capacity throughout the digestive tract.

Excessive acidity in the stomach is a primary factor in the development of gastric ulcers in horses. The problem is prevalent in racing horses, where it is estimated that up to 90% of performance horses suffer from gastric ulceration during their careers.  Laboratory studies at KER showed that BMC increases buffering capacity 2.7?fold in acid conditions typically seen in the stomach. In vivo studies further confirmed the buffering capacity of BMC, as horses fed sweet feed with BMC had greater gastric fluid pH one-hour post feeding (6.2 vs 2.0) than those fed sweet feed alone. When pH is below 4 there is an increased risk of ulcer development. 

Further down the digestive tract, excessive acid production in the large intestine can lead to hindgut acidosis. Hindgut acidosis often occurs in horses with high grain intakes or in horses grazing rich pasture. Symptoms of hindgut acidosis include poor appetite, loose manure, chronic colic and stereotypic behaviours such as wood?chewing and stall?walking. Acute hindgut acidosis can lead to intestinal damage and even laminitis. The subsequent research at KER showed that a diet including BMC improved hindgut buffering capacity by 54% compared to the same diet without BMC supplementation. The buffering properties in both regions of the gastrointestinal tract will be of benefit to all horses, in particular during stressful periods such as weaning, yearling preparation and racing. 

The multi-dimensional results could prove to be pivotal in protecting the skeletal health of racehorses.  Globally, leading feed companies in the US and UK have embraced the research by moving to include the active components in manufactured feed products, as well as offering availability as a stand-alone product, KERx Triacton.  Now in WA, astute breeders and trainers are opting to utilize the research by incorporating Triacton into their feeding practices via Milne Feeds.   Through their global community of brand alliance partners, prolific researchers, KER are committed to making the latest nutrition research and innovation accessible for horse people in all areas, including right here in Western Australia. 

 

References

 

Firth, E.C., Van Weeren, P.R., Pfeiffer, D.U., Delahunt, J. and Barneveldt, A. (1999) Effect of age, exercise and growth rate on bone mineral density (BMD) in third carpal bone and distal radius of Dutch Warmblood foals with osteochondrosis. Equine Veterinary Journal, Suppl. 31, 74-78.

 

Kobayashi, M., Ando, K., Kaneko, M., Inoue, Y., Asai, Y. and Taniyana, H. (2007) Clinical Usefulness of the Measurement of Bone Mineral Content by Radiographic Absorptiometry in the Young Thoroughbred. Journal Equine Science, 18, 99-106

 

Nielsen, B.D., Potter, G. D., Morris, E. L., Odom, T. W., Senor., D. M., Reynolds, J. A., Smith, W. B. and Martin., M . T (1997) Changes In The Third Metacarpal Bone And Frequency Of Bone Injuries In Young Quarter Horses During Race Training - Observations And Theoretical Considerations. Journal Equine Veterinary Science 17(10), 541-549.

 

Pagan, JD., Swanhall, A., Ford, E., Mulvey, E., & Huntington, PJ. (2018) Mineral and Vitamin Supplementation Including Marine Derived Calcium Increases Bone Density in Thoroughbreds.

Proc Australian Equine Science Symposium 7, In Press


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