What every horse owner should know about equine osteoarthritis

Osteoarthritis (OA) is a progressive disease that involves the breakdown of joint cartilage and the underlying bone. It is one of the major causes of lameness in horses, which in turn is the main cause of wastage in the equine industry. In the UK, one in every five horses requires veterinary attention at least once a year due to lameness. Amongst athletic horses, lameness is the most common condition in poor performers, and osteoarthritis is the main cause of early retirement.

There are a number of factors that lead to equine OA. Primary OA develops from daily ‘wear and tear’ causing progressive joint breakdown: the greater and more repetitive the insult on the joints, the faster the damage develops, and the sooner the symptoms arise. Secondary OA is the result of an often-severe injury that starts the joint damage, such as an acute blow, infection from a wound, or even a serious injury to the tendons and ligaments around the joint.

Athletic horses are at increased risk of OA because of both initiating and perpetuating factors, including equestrian discipline and training intensity. In fact, some of the very early signs of OA are poor performance and subtle behavioural issues due to low-grade pain, which will gradually worsen. At this early stage, lameness is often not detectable and early joint changes are not visible on standard x-rays, making a definitive diagnosis quite challenging. For this reason, cooperation between horse owners and vets becomes key.

Subchondral bone: what it is and what role does it play?

OA is a disease of the whole joint. If we start from the centre of the joint, the articular cartilage is the smooth tissue that covers the ends of bones where they come together in a joint. It contains chondrocytes, the basic cartilage cells, producing large molecules that form a sponge-like network that draws in and holds water. Because of its structure, the cartilage acts like a firm cushion between bones, distributes loads evenly and allows the bones to glide against each other. Repetitive or sudden trauma, deficient nutrition and genetics can cause cartilage damage and initiate OA.

Beneath the articular cartilage, a thin layer of subchondral bone provides shock-absorption capacity and drives blood vessels and nerves to support and nourish the cartilage. The subchondral bone undergoes remodelling to adapt to mechanical forces during training, but uneven loading cause damage to the subchondral bone, which becomes stiffer and less adaptative to weight bearing forces and deprives the articular cartilage from mechanical and metabolic support. We can see how the cartilage and subchondral bone form a unit even at the outset of equine OA, which is why they become a combined target for nutritional support.

Finally, we have tendons, ligaments and the capsule stabilising the joint and preserving its range of motion. The inner lining of the joint capsule produces synovial fluid, which lubricates the joint for optimal motion.

Management options for horses with OA

Once diagnosed, there are multiple treatment options for horses with OA. The efficacy of surgery will depend on how advanced the case is, meaning that early treatment is often the best bet. This means a combination of rest and adaptation of the horse’s training load, the use of steroids and other anti-inflammatories against the inflammation-breakdown cycle of the joint, and agents against bone remodelling and loss of mineral density, such as bisphosphonates.

Motion is lotion: the role of nutrition in joint protection and support

Studies suggest that functional ingredients in equine complementary feed may contribute to optimise both quality of life and athletic performance in horses. Your veterinarian is the first point of contact for advice on complementary feed to maximise the management of your horse’s diet.

Joint supplements contain precursor molecules for the components of a healthy functioning joint, such as glucosamine and collagen, and compounds that provide cartilage protection, improve comfort and promote a healthy joint environment.

New Ekyflex Arthro EVO: the inside scoop

It becomes obvious that joint health is a crucial part of the management of active horses, regardless of their exercise level. Protecting the horse’s joints essential to ensure free movement and improve performance. Ekyflex Arthro EVO demonstrates Audevard’s commitment to meeting the demands of a constantly growing field such as the equine industry. Recent years have seen an evolution of the management of the equine musculoskeletal system, taking care of the whole joint and not only of the articular cartilage. This is in line with human medicine, where the crucial role of subchondral bone has been acknowledged for a number of years. The equine industry has also experimented a shift towards plant-based sources when it comes to ingredients in complementary feeds (2) and an overall more natural approach to horse healthcare.

Audevard works closely with and for equine vets across Europe to translate the latest scientific and technological advances into a precise, more concentrated formulation of Ekyflex Arthro that is an evolution from our flagship orthopaedic supplement at multiple levels, using latest generation ingredients titrated for effectiveness. It is also the first equine chondroprotective formula without animal by-products or artificial colourings, with a focus on plant-based sources.

  • 100% plant-based glucosamine sulphate: it has a chondroprotective effect, and it supports the production of glycosaminoglycans (GAGs), chondroitin and hyaluronic acid. Glucosamine helps preserve joint mobility and length of stride (4). Studies have shown that glucosamine sulphate is best absorbed and incorporated into the joint (7), hence why this form is incorporated into Ekyflex Arthro EVO.
  • Peptagen II®: collagen is the most important protein produced by the body, and it is a crucial component of articular cartilage. Amino acids are the basic building blocks of protein, and any ingested protein will be broken down by the gut into smaller units before being absorbed. Research shows that small groups of amino acids, called peptides, are more easily absorbed and incorporated into target tissues than whole proteins like collagen (3). Ekyflex Arthro EVO feature a unique blend of peptides, Peptagen-II® that contain the exact necessary amino acids to form collagen once incorporated into the cartilage more efficiently, playing a key role in preserving its structure and function.
  • Unsaponifiables from avocado and soy (ASU): these are organic components of fatty acids derived from the extraction of natural oils, avocado and soy. Over 23 published papers have backed their efficacy at improving stiffness1, and at protecting the joint environment (5).
  • Proanthocyanidins (PAC): grape seed extract and grape skin are the source of these natural polyphenols, which can protect the horse’s subchondral bone and offset the demands from regular training, with a proven effect at improving stiffness (8).
  • MSM: methyl-sulphonyl-methane is a naturally occurring chemical in green plants but also in animals, where it acts as a sulphur-giving molecule. MSM is an essential nutrient for cartilage and it also has antioxidant effects, shielding the joint environment against free radicals produced during exercise (6).

In addition to the previous formula (of which 65% of ingredients remain), Ekyflex Arthro EVO includes these five functional ingredients that have been selected and validated by the veterinary technical team at Audevard, to ensure a triple level of joint protection: cartilage, synovial fluid and subchondral bone. As always, all ingredients are listed in full, to ensure complete transparency and build confidence and trust amongst vets and horse owners. With this innovation, Audevard brings an orthopaedic solution with a more respectful formula, designed to free the movement of the horse's joints to achieve their full potential.

References

1.Appelboom T. et al. (2001) ‘Symptoms modifying effect of avocado/ soybean unsaponifiables (ASU) in knee osteoarthritis’. Scandinavian Journal of Rheumatology 30, pp. 242-247.

2.CBI Ministry of Foreign Affairs – What is the demand for natural food additives on the European market? 23rd December 2020.

3.Dobenecker B. et al. (2018) ‘’Specific bioactive collagen peptides (PETAGILE®) as supplement for horses with osteoarthritis: a two-centred study’. Journal of Animal Physiology and Animal Nutrition 102 (Supp.1), pp. 16-23.

4.Forsyth R.K. et al. (2006) ‘Double blind investigation of the effects of oral supplementation of combined glucosamine hydrochloride (GHCL) and chondroitin sulphate (CS) on stride characteristics of veteran horses’. Equine Veterinary Journal Suppl. 36, pp. 622-625

5.Kawcak C.E. et al. (2007). ‘Evaluation of avocado and soybean extracts for treatment of horses with experimentally induced osteoarthritis’. American Journal of Veterinary Research No 6, pp. 68

6.Maranon G. et al. (2008) ‘The effect of methyl sulphonyl methane supplementation on biomarkers of oxidative stress in sport horses following jumping exercise’. Acta Veterinaria Scandinavica 50 (45), pp. 1-9.

7.Meulyzer M. et al. (2008) ‘Comparison of pharmacokinetics of glucosamine and synovial fluid levels following administration of glucosamine sulphate or glucosamine hydrochloride’. Osteoarthritis and Cartilage 16, pp. 973-979.

8.Woo Y.J. et al. (2011) ‘Grape seed proanthocyanidin extract ameliorates monosodium iodoacetate-induced osteoarthritis’. Experimental and Molecular Medicine 43, pp. 561-570.

Written by: Dr Marga Mas DVM PGDip MRCVS (Guest Author)