b'CRIBBING and COLICfrom crib-biting to cope with experi-enced stress.A handful of other theories about why horses crib exists, but its likely caused Consequences of cribbing includeby more than one factor. The cause could not only colic but also dental wearpotentially involve any combination of and damage to barn surfaces. genetics (although researchers havent yet identified candidate genes), differences in physiological mechanisms, management factors such as weaning protocol and housing/socialization, as well as diet. The Consequences of CribbingIndeed, cribbing might soothe a stressed horse, but the calm doesnt come without a cost. Concerns associated with this stereotypy include: Dental abnormalities and wear;Temporohyoid osteoarthropathy abnormalities of the temporohyoid joint and associated structures that anchor the hyoid apparatus (voice box) to the skull; Gastric ulcers;PAULA DA SILVA PHOTOS Weight loss/poor condition due to time spent cribbing rather than consuming food; and Poor performance.Colic is another major concern as-sociated with crib-biting horses, says In 2018 Arash Omidi, DVM, PhD, pro- The rationale is that animals af- Louise Southwood, BSc (Vet), Dipl. fessor of animal health management atfected by stereotypies are supposed toACVS and ACVECC, a professor in emer-Shiraz University, in Iran, and colleaguesbe cognitively less flexible compared togency medicine and critical care at the described an alternative explanation forhealthy controls due to sensitization of aUniversity of Pennsylvanias School of cribbing: the oxidative stress hypoth- specific part of the basal ganglia, a brainVeterinary Medicine, in Kennett Square. esis. Oxidative stress occurs when thearea instrumental to learning, BrieferShe focuses her clinical and research ef-antioxidants in the body that hunt downFreymond says.forts on equine gastrointestinal diseases, and squelch damaging free radicals (mol- In that study (TheHorse.com/166468)with an emphasis on colic.ecules with unpaired electrons) decrease.horses had to perform two reversalAfter years of speculating that colic oc-Trace elements such as selenium play im- learning tasks to measure cognitive flex- curs more frequently in horses that crib, portant roles in enzyme systems that helpibility. Specifically, they had to differenti- researchers have finally provided consis-protect the body from oxidative stress.ate between two signals placed on flaps: atent data confirming this association. In Therefore, reduced selenium levels mightblack versus a white cross, or a black ver- 2011, for example, Claire Scantlebury, play a role in the biology of cribbing.sus a white circle. If the horse chose thePhD, MRCVS, and her U.K. colleagues at In their study, Omidi and colleaguescorrect flap signal, the handler gave himthe University of Liverpool reported that collected blood samples from horses thata food reward. Briefer Freymond and hercribbers were 12 times more likely to were not cribbing and during or immedi- team found that both the stereotypic andsuffer recurrent colic than noncribbers. ately after cribbing. They found serum se- control horses required a similar numberIn 2014 another group of scientists from lenium levels to be significantly lower inof trials to complete the cognitive tasks.Liverpool conducted a questionnaire-cribbers than noncribbing controls, andThese data, therefore, challenge thebased study of owners of cribbing horses. those values were lowest while cribbing.widely held belief that crib-biting horsesOf the 365 qualifying horses, owners Other researchers theorize that horsesare cognitively impaired in their flexibil- reported that 130 (35%, 38 cases per exhibiting stereotypic behaviors haveity of learning, she says. It is important100 horse years) had experienced one brain dysfunctions. So, in a 2018 study,to note that horses in this study wereor more colic episodes, for a total of 672 Briefer Freymond and colleagues com- allowed to partake in crib-biting duringcolics over a 12-month period, with 13 pared the ability of cribbers and horsesthe study and that it is still possible thatrequiring surgery. Colic prevalence in the without stereotypies to complete variouscognitive underperformance may occurgeneral horse population ranges from 3.5 learning tasks.in stereotypic horses if they are preventedto 10.6 cases per 100 horse years.14November 2019The Horse|TheHorse.comCribbingColic USE2.indd 14 9/25/19 10:43 AM'