The observance of a cresty neck in a horse indicates some level of metabolic sickness and reflects more than just a fat horse.
Although the fat or obese horse is burdened with a form of metabolic illness, the appearance of a cresty neck signals further metabolic complications along the continuum of diseases associated with obesity.
The cresty neck that occurs along the upper curve of the horse’s neck is much different than the well-rounded and crested neck that can be found in a conditioned athlete.
The two are easily differentiated by general appearance and feel. A muscular ‘crested’ neck has a strong and vibrant feel whereas a cresty neck will jiggle, feel spongy, cushiony and/or boggy.
Its development is closely associated with the onset of a medical condition called equine metabolic syndrome (EMS), a cluster of metabolic derangements and endocrinopathies, including insulin dysregulation, obesity and/or regional adiposity, with laminitis or founder. Many horses with cresty necks are susceptible to chronic low-grade inflammation of the laminae within the hoof capsule and appear intermittently stiff gaited and ‘tender footed.’
If left unchecked these horses experience a gradual decline in hoof quality and functionality. Once horse owners become aware of its significance the cresty neck becomes a valuable tool to guide management strategies to reduce the risk of laminitis. Both the size of the cresty neck and its tissue quality have been found to be fairly accurate predictors for the onset of laminitis.
Researchers have identified and developed a scoring system to quantitate the risk.
Like abdominal fat in humans, neck crest fat in horses has been suggested to be specifically associated with metabolic disease. The novel cresty neck scoring system is on a scale of zero to five where a score of zero equals no visual appearance of a crest and a score of five equals enormous and permanently drooping to one side.
An appreciable hardening or turgor of the ‘crest’ tissue has also been found to coincide with the early onset of a laminitic episode. The crest of the horse’s neck is made of fibro-fatty subcutaneous adipose tissue similar in texture to high-density foam and its foam-like nature is very sensitive to electrolyte and water fluxes in the horse’s body.
As a result the tissues in the crest of the neck will take up water like a sponge becoming hard or oedematous with subtle electrolyte imbalance within the body. When the electrolyte imbalances are corrected the fluid then returns to its normal compartments and the crest softens.
At the basic level electrolytes are minerals dissolved in bodily fluids and the body’s electrolyte balances can be directly influenced by the mineral content of the horse’s pasture intake. Pastures are an ever-changing being and their mineral profiles on any one day are subject to many influences, one of which is weather. Weather drives growth patterns of the forage on pasture and can impart significant fluxes in the mineral profiles within the growing plant matter. This is especially notable during growth spurts in forage typically seen during the periods of early spring, fall, or heavy rainfall. The shift in the mineral profile of pasture grasses directly affects the horse’s own electrolyte and mineral profiles.
Although all the details of mineral imbalances associated with the rapid growth of pasture are not thoroughly understood, it is important to acknowledge ‘pasture-related laminitis’ is a much bigger picture than the traditionally held belief implicating the spike in sugars and starches in the new grasses. The ‘firming up’ and hardness of the crest from its soft and spongy state coinciding with periods of changing plant growth can be vital information just prior to a bout of laminitis.
Short-term management of affected horses involves immediate removal of the horse from the pasture on to a hay diet. It is also crucial to ensure the availability of mineral and salt resources for horses on pastures. This measure allows the horse to buffer the shifting mineral and electrolyte profiles as a result of fluctuating plant growth and mitigate episodes of laminitis.
The cresty neck on a horse needs to be regarded with a wary eye as it is a harbinger of metabolic problems including a risk factor for laminitis.
Identifying and addressing mineral imbalances is as equally important to the rehabilitation of these compromised equines as is the sugar and starch content of the pasture forage.