New research published in the Journal of Veterinary Behavior suggests there is no direct inherent link between crib biting and equine gastric ulceration (EGUS) but rather that both conditions are linked to environmental and physiological stress.
- Crib biting horses did not differ in G-Cell concentrations compared to non-cri biting horses.
- Crib biting horses did not differ in stomach pH compared to non-crib biting horses.
- EGUS was observed in crib biting and non-crib biting horses.
- Environmental and cellular stress are postulated to be the link between conditions.
Previous research had tried to find a relationship between crib biting and EGUS and many people believe that horses crib bite because the additional saliva provides relief from ulcers by protecting the stomach lining from acidic gastric juices, however, the research so far has failed to provide evidence to this effect.
A team of researchers from the School of Equine Management and Science, Royal Agricultural University in the United Kingdom hypothesised that, if there was a direct link between crib biting and ulceration, the stomachs of crib biting horses would have a different anatomy and physiology to that of non-crib biting horses.
Their two-part experiment was conducted using 24 cadaver stomachs collected from an abattoir. They examined sections from the fundic and pyloric mucosa (the stomach lining in two different regions of the stomach) to identify gastrin producing G-cells and also tested the pH of the mucosa and digesta (stomach contents). Gastrin is a hormone that stimulates the secretion of gastric acid.
They also scored the horses for gastric ulceration.
The researchers found no difference in the anatomy and physiology between the two groups in G-Cell concentrations and pH, and suggest that the likely link between the conditions is environmental and cellular stress.
In practical terms, it is very unlikely stomach pain leads horses to crib bite, it's just that horses that crib bite and horses that have EGUS are both suffering from stress.
The article “Crib Biting and Equine Gastric Ulceration Syndrome: do horses that display oral stereotypies have altered gastric anatomy and physiology?” by S.P. Daniels, L.Scott, I. De Lavis, A. Linekar and A.J. Hemmings is published in the Journal of Veterinary Behavior and the abstract is available here.