Prevalence of Nontypical Behaviors in Racehorses

Stereotypies, or abnormal repetitive behaviors or actions, are sometimes seen in horses that are confined to stalls for many hours a day. They may also be seen occasionally in horses that are pastured, but these unusual behaviors are far more common in confined horses.

Cribbing, weaving, licking, wood-chewing, and coprophagy (eating of manure) are examples of stereotypies. Depending on the severity of the condition and amount of time spent each day in the behavior, some stereotypies are only a bit odd while others can actually compromise equine welfare.

Researchers from the Universidad Austral de Chile carried out an evaluation of the prevalence and factors associated with stereotypies and other undesired behaviors in a population of 743 Thoroughbred horses at two Chilean racetracks in Santiago. The horses were of varying ages and sexes. The researchers recorded detailed information about bedding type, feeding protocol, training routine, and how much social contact the horse had with their peers (none, visual, or visual and tactile). The team also recorded stereotypic or abnormal behavior as well as any methods that were used to prevent or impede those behaviors.

Abnormal behaviors such as weaving, stall walking, nodding, pawing, and stall kicking were grouped as habits with a locomotor origin. Cribbing, wood chewing, coprophagia, consumption of bedding materials, and eating or licking other objects were seen as oral abnormal behaviors.

Results showed that 82 horses (11%) performed some stereotypy or abnormal behavior. This figure is somewhat lower than what has been found in some similar studies in other countries. Five horses performed more than one abnormal behavior, and one performed three abnormal behaviors.

Although both racetracks had similar management practices, horses stabled at Racetrack B showed significantly more abnormal behaviors, with the largest number of horses engaging in cribbing.  At Racetrack A there were fewer abnormal behaviors, with weaving reported most often. Some behaviors including bedding consumption, pawing, and eating or licking objects were seen only at Racetrack B. In this study, more mares exhibited stereotypic behaviors than did stallions or geldings.

For the entire study population, 85% of the horses were bedded with wood shavings, with the rest being bedded with straw. Bedding with wood shavings was found to be a significant risk factor for horses exhibiting abnormal behaviors.

Visual contact with other equids was available to 86% of stalled horses, while the rest had no visual or tactile contact with other horses. There was no significant association between the availability or absence of visual contact and the development of stereotypies, a finding that is contrary to previous research.

All study horses spent an average of 86 minutes per day outside their stalls. Because this time was very similar for all horses, it was not possible to evaluate whether time in or out of the stalls had any influence on the development of stereotypies.

Horse managers attempted to control the abnormal behaviors in 43% of the cases, with many of the methods involving physical restriction. Researchers felt that restraining the animals did not address the root of the problem and might in some cases become a risk for the welfare of the animal due to increased stress.

All horses consumed oats and alfalfa hay, and just over half (54%) received feed two or three times daily. The remaining horses were fed once daily. A suggestion from the study team was to increase both the percentage of forage in the meals and the frequency of feeding.

Racing, a growing industry in Chile, is not governed by any policies regarding the housing and management of the horses, most of whom spend their entire competitive lives housed at the racetrack yards. Because 11% of the racehorses observed in this study presented at least one abnormal behavior, the results suggest that some changes to the management and husbandry would be beneficial for their welfare.