A study exploring factors behind crib-biting in horses found that such horses produced more gastrin – the hormone that stimulates the production of stomach acid – when fed concentrated feed that horses that did not show the vice.
Their findings have been published online this month in the Journal of Equine Veterinary Science.
The researchers from Michigan State University, and two Alabama universities, Auburn and Tuskegee, had hypothesized that crib-biting horses would have more gastric mucosal damage and higher serum gastrin response to concentrate feeding than non-crib-biting horses.
Eighteen mature horses, half of which were crib-bitters, were used in the study.
Horses were maintained on pasture with free access to hay and were fed a pelleted concentrate diet twice daily.
The number of crib-bites and the duration of cribbing bouts were recorded in a 24-hour period.
Endoscopic examinations of the squamous mucosa were performed and gastric fluid was sampled 24 to 28 hours following feed removal.
After the endoscopic examinations, the horses were returned to pasture for 72 hours.
Blood was collected 12-hours after feed removal, and then 60 minutes and 120 minutes after consuming one kilogram of concentrate.
The researchers found no differences in the number or severity of ulcers, prevalence of hyperkeratosis, or baseline gastric pH between the two groups.
Serum gastrin concentration at 60 minutes and 120 minutes after the concentrated feed tended to be greater, respectively, in crib biters than in non-crib-biters following feeding of concentrate.
Crib-biting behavior in horses maintained on pasture was not associated with gastric mucosal damage, they found. However, consumption of concentrate feed resulted in greater serum gastrin concentration in crib-biting horses.
Assessment of Gastric Ulceration and Gastrin Response in Horses with History of Crib-biting.
Carissa L. Wickens, Cynthia A. McCall, Steve Bursian, Reid Hanson, Camie R. Heleski, James S. Liesman, Wendell H. McElhenney, Nathalie L. Trottier.
Journal of Equine Veterinary Science – 18 March 2013 (10.1016/j.jevs.2012.12.004)