A cresty neck score provides an indication of  the amount of fat in the crest that runs along the topline of an equid’s neck. Scores range from zero to five. Zero is scored for horses in which no crest fat can be seen or felt. Five is scored when the crest is so large it permanently falls to one side (Carter et al 2009).

A cresty neck has been recognised as an important site of fat deposition. It has been included as a potential sign of the equine metabolic syndrome (EMS) since the syndrome was first defined (Johnson 2002).

Fat and Hormones

Fat tissue not only stores energy but also plays an important role in the synthesis and release of hormones that are involved with metabolism including that of insulin. Insulin dysregulation is one of the most significant risk factors for endocrinopathic (hormone-linked) laminitis in horses. Whilst the total amount of fat carried in the body is an important consideration, the location(s) where the fat is deposited might also be relevant to its effects on health.

Although a cresty neck has long been recognised to be more common in equids with insulin dysregulation, two recent studies have provided further detail on the relationship.

UK Study

One study of ponies in the UK analysed the results of 1,763 oral sugar tests (used to help determine if the pony has insulin dysregulation or not) from 367 ponies. In this group two-thirds of ponies with high cresty neck scores of 4/5 or 5/5 had medium or high insulin responses. However, only one-third of ponies with the lowest cresty neck scores of 0/5 or 1/5 had medium or high insulin responses.1

Whilst having a cresty neck increased the chances of having insulin dysregulation, it was not more important than other features such as the pony age, having an overall increase in body condition, or having fatty deposits above the eyes.

Importantly, this large study showed that whilst insulin dysregulation is more common in equids with cresty necks, it still occurs in equids without crest fat. Therefore, ID should not be ruled out in horses that don’t fit the typical EMS description. Testing is always advisable. Talk to your veterinarian if you are concerned.

Australian Study

Another study of ponies in Australia2 also investigated the correlation between neck crestiness and the likelihood of metabolic dysfunction.

Scientists at Queensland University of Technology examined 26 ponies. They assigned each a body condition score (BCS) as well as a cresty neck score (CNS). Based on these assessments, the ponies were divided into three groups: Those with a cresty neck but moderate body condition; those who were obese with a cresty neck; and those who were in moderate body condition and did not have a cresty neck. The researchers also used oral glucose tests as an alternative way to determine whether the pony had insulin dysregulation or not.

The researchers found that ponies with a cresty neck score of 3 or greater were five times more likely to be insulin-dysregulated than those with a CNS below 3. That was irrespective of their body condition scores. However, similar to the UK study, not all ponies with the cresty neck had insulin dysregulation, and insulin dysregulation also occurred in some ponies without cresty necks.

Again, if you are concerned, talk to your veterinarian about testing for insulin dysregulation (ID).

In those equids with cresty necks that do not have insulin dysregulation, an important question is whether they are at higher risk of developing insulin dysregulation in the future. Further research is required to answer this question.

In the meantime, if your horse or pony has a cresty neck, it is worth working with your nutritional advisor on the most appropriate diet for that animal. Repeat monitoring of the ID status might be invaluable, especially if the equid initially test negative for ID.

laminitis risk cresty neck mini mule
Cresty neck as seen from the top. Kimberly S. Brown photo

Final Words

Therefore, horse owners should recognize that a cresty neck increases the risk of having insulin dysregulation and might be a useful prompt for blood testing. However, it Is only one of several features found in equids with ID.

Early detection of insulin dysregulation is likely to be useful for the prevention of laminitis and it would be ideal to identify equids with ID based on their physical features. Several features, including a cresty neck, can give us clues. However, none are as reliable as insulin testing. This is important because the association between insulin dysregulation and equine laminitis has been well established.1

References 

  1. Factors associated with insulin responses to oral sugars in a mixed-breed cohort of ponies. 2023. Edward J. KNowles, Patricia A. Harris, Jonathan Elliott, YuMei Chang, Nicola J. Menzies-Gow. Equine Veterinary Journal.
  2. The Cresty Neck Score Is an Independent Predictor of Insulin Dysregulation in Ponies. 2019. Fitzgerald, D.M.; Anderson, S.T.; Sillence, M.N.; de Laat, M.A. PLoS One. 2019 Jul 24;14(7):e0220203. doi: 10.1371/journal.pone.0220203. PMID: 31339945; PMCID: PMC6655749. 

Further Reading