Feeding for joint health
Team Marketing | 06.10.20Athletic competition often requires horses to run, jump, turn, start and stop, placing an enormous strain on the skeletal system. As such, a performance horse may fail to reach its athletic potential because of injuries and diseases of joints, which are the most common causes of lameness. As joint problems can be a limiting factor in career longevity of athletic horses, care and maintenance of joints are a major concern among horsemen.
The Equine JointA joint is the union of two bones, regardless of the location in the body. A joint allows controlled movement of bones relative to each other, thus allowing the skeleton to move. Joints found in the leg of a horse endure incredible pressure during movement. In a healthy joint, the ends of the bones are coated with a thin layer of articular cartilage reducing friction. Bones are also surrounded by a joint capsule with a tough outer layer (to connect the bones and protect the joint) and a permeable inner layer or synovial membrane. The membrane secretes synovial fluid, a slippery, viscous liquid, providing essential lubrication and allows the passage of nutrients and other elements from the bloodstream. Synovial fluid is nutrient-rich containing proteins, enzymes, water, leukocytes and a key ingredient; sodium hyaluronate, which is responsible for the fluid’s elastoviscous qualities. Sodium hyaluronate (formerly known as hyaluronic acid) is a negatively-charged sugar chain or glycosaminoglycan (GAG), which arranges itself in complicated coils, adapting to the pressure changes in the joint capsule as the horse moves. It assures the unhindered passage of metabolites to and from tissues throughout the joint and also serves as a stabilizer and shock absorber for the structures that are undergoing continual, changing mechanical stresses. Articular cartilage, the other main shock-absorbing component of a joint, is an efficient but flawed structure. Its structural framework is a web of collagen fibers with cells called chondrocytes scattered along the matrix. Chondrocytes produce giant proteoglycan molecules that bind the GAGs. The GAGs in turn extract and loosely hold large amounts of positively-charged water molecules. When cartilage is damaged, there is a decrease in the number of GAGs; therefore, the cartilage holds less water. Cartilage conforms to the bone surfaces for a tight fit between weight-bearing bones, it spreads pressure evenly over a broad area and manages the water in its matrix, squeezing it out when the joint is under pressure and drawing it back in when the joint is not under pressure. This in-and-out movement of the fluid transports nutrients throughout the cartilage. However, there is a downside to cartilage as it has no blood or nerve supply of its own, so cartilage has little or no ability to heal or repair itself. Although cartilage performs admirably under normal conditions
Joint DamageLameness, change in the normal range of motion of a joint, can result from damage to any of the tissues associated with the joint, such as:
- Disrupted ligaments, tendons, or muscles due to injury.
- Disease of the supporting bone can lead to collapse of the joint surface .
- Damage to the articular cartilage, such as the breakdown of collagen and loss of proteoglycan resulting in weakened cartilage, which loses its smooth articulating surface.
- Damage to the synovial membrane and changes in the makeup of the joint fluid result in alternations in normal joint viscosity.