Surprising findings in British research into cresty necks

Researchers who monitored fat on the necks of 96 British horses at pasture were surprised to find the crest tended to be bigger at the end of winter than the end of summer.

The findings are surprising, given that previous research has shown that horses tended to be fatter overall at the end of summer than the end of winter.

The findings by the research team at the University of Bristol suggest that changes in fat deposits on the neck did not follow the same seasonal trends as general obesity in the horse population.

Cresty necks in horses and ponies have been associated with a greater risk of metabolic health problems.

Sarah Giles and her colleagues assigned a Cresty Neck Score to 96 herd-living leisure horses in North Somerset who had access to pasture  for at least six hours a day.

The scores were assigned on the scale, which runs from 0 to 5, at the end of winter and the end of summer. The same observer was assigned the same animal for the winter and summer measurements.

In a bid to associate any risk factors with cresty necks, owners were asked to complete questionnaires.

The researchers found, to their surprise, that the winter Cresty Neck Scores were significantly higher than the summer values. They found that 45.83 percent of the horses had a score of 3 to 5 at the end of winter, falling to 33.33 percent at the end of summer.

The study team, whose findings have been published in the open-access peer-reviewed journal, BMC Veterinary Research, said the higher winter scores were the opposite seasonal variation observed for general obesity in horses.

Ponies were more likely to have fatter necks in both seasons, especially so Britain’s native pony breeds. Ponies between 114–134cm appeared to be at greatest risk.

Horses or ponies with a history of laminitis were more likely to have a score of 3 to 5.

Although feeding supplementary hay during the winter months was relatively rare in the study population – just 6.38 percent – this increased the odds of a score of 3 to 5.

Horses with a complete change in feeding regimen between seasons showed the highest odds of a score of 3 or above.

The researchers found that fewer cases of a cresty necks were found among the animals kept in bigger herds.

“There are two possible major reasons why neck crest adiposity differs to general adiposity in this way: this is either a real physiological effect, or a methodological anomaly with the cresty neck score itself,” Giles and her colleagues reported.

However, they argued that any potential observer error was ultimately unlikely to fully explain the extent of differences in the prevalence of cresty neck observed between seasons in the study population.

Giles was joined in the research by Christine Nicol, Sean Rands and Patricia Harris.

Assessing the seasonal prevalence and risk factors for nuchal crest adiposity in
domestic horses and ponies using the Cresty Neck Score
BMC Veterinary Research
doi:10.1186/s12917-015-0327-7

The full study can be read here.