Crib biting and equine gastric ulceration syndrome: Do horses that display oral stereotypies have altered gastric anatomy and physiology?

Abstract

Equine Gastric Ulceration Syndrome (EGUS) and Crib biting are two separate conditions suffered by horses. Previous research has hypothesised causal relationships between these two conditions, whereby the behavior is driven by a requirement to stimulate saliva production to buffer gastric juice. However to date there is limited empirical evidence to support this notion. To identify if the anatomy and physiology of the equid stomach differed in crib biting (CB) horses and non-crib biting controls (N-CB) a two part experiment was conducted using cadaver stomachs. Twenty four stomachs (n=12) CB and (n=12) N-CB were collected from an abattoir. Duplicate 1.5 cm squared sections were taken from the fundic and pyloric mucosa for histology and H&E staining to identify gastrin (G) producing cells. Slides were scored using an adapted four point scale. A further 18 stomachs, (n=9) CB and (n=9) N-CB were collected to test the pH of the mucosa and digesta from the fundic and pyloric regions. G cell concentrations were analysed by Mann Whitney Utest. Stomach content pH was analysed by one-way ANOVA and L.S.D post hoc. Relationships between digesta and mucosal pH were evaluated by correlation. In both parts of the study there was no difference between the G-cell concentration (P>0.05) and pH (P>0.05) between CB and N-CB horses. There was a positive correlation between digesta and the mucosal surface of pyloric region in CB horses (R 2 0.66, P<0.001), but not in N-CB horses. These findings suggest, from cadavers, that CB and N-CB stomachs are not anatomically nor physiologically different. It is plausible that there is no direct inherent link between CB and EGUS rather that both conditions are linked to environmental and physiological stress.

Common Feeding Practices Pose A Risk to the Welfare of Horses When Kept on Non-Edible Bedding

“…However, a direct connection between the behavioural disorder "crib-biting" in horses and the occurrence of stomach ulcers has not been proven. This indicates that both diseases result from housing and management related stress and are not interdependent [52,53]. Consequently, horses have evolved in a way that requires continuous food intake, from an ethological (natural behaviour) and a physiological (digestive system) point of view.…”

Cólica Em Equinos

“…Por meio da ação de músculos circulares, movimentos peristálticos formam anéis de constrição na parede esofágica, reduzem o lúmen e empurram o bolo alimentar aboralmente. Ao chegar à porção distal do esôfago, o esfíncter distal se abre e a ingesta entra no estômago (DANIELS et al, 2019).…”

“…O intestino delgado dos equinos possui comprimento médio de 20 metros, sendo dividido em: duodeno, jejuno e íleo (DANIELS et al, 2019). A mucosa possui vilosidades de 0,5 a 1 mm, revestidas por células epiteliais com microvilosidades destinadas a aumentar a superfície absortiva, células caliciformes secretoras de muco e glândulas secretoras de suco entérico (RIBEIRO et al, 2019).…”

“…Essa característica evolutiva está relacionada ao hábito de se alimentar várias vezes ao dia (QUEIROZ, 2019). A bile emulsiona as gorduras presentes na dieta por ação digestiva da lípase (DANIELS et al, 2019). A digestão química no intestino delgado acontece por meio da ação de enzimas que dissociam quimicamente o alimento em partículas menores (FIELDING, 2018).…”

Changes in Management Lead to Improvement and Healing of Equine Squamous Gastric Disease

“…Cribbing and other stereotypies are associated with ESGD and considered to be coping mechanisms, suggesting a link with stress [18,19]. Daniels et al found no difference in gastric anatomy and physiology between crib-biting and non-crib-biting horses and suggested that there is no direct link between crib-biting and EGUS, but that both may be related to physiological and environmental stress [20]. It has also been demonstrated that horses with EGUS experience more oxidative stress than healthy horses [21].…”