Stereotypical behaviours are common in domestic horses. While preventing/reducing the risk of these behaviours with species-appropriate feeding plans is the goal, oftentimes these stereotypic behaviours have already developed. Identifying the presence of behavioural stereotypies is important when considering the individual animal. While the specific cause behind these behaviours has yet to be identified, stress and management conditions which do not suit natural behaviours increase development risk [1].
Stereotypical behaviours are thought to be adaptive attempts to solve problems, and do not act as actual solutions to the causative issue. When the animal cannot find a solution, the initially adaptive behaviour becomes fixed and performed out of context (Hothersall and Nicol, 2009).
Stereotypic behaviours cause stress on the animal’s body, can contribute to increased risk for GI disorders (colic, ulcers, acidosis), can damage facilities and generally reflect a horse who is trying to cope in an environment [1,2]. So, when considering the nutrition of the stereotypic horse, we aim to manage and support the horse’s well-being by identifying altered nutritional requirements and meeting these requirements with dietary changes to minimize motivation for the behaviour, while utilizing environment changes to redirect the behaviour.
Identifying (& Meeting) Nutritional Requirements
In a study where horses were fed for weight gain (dietary energy in 44-64% excess of requirement), a horse who cribbed actually lost weight throughout the study [3]. This suggests that horses who display stereotypic behaviours might have higher energy expenditures than non-stereotypic horses.
Recent advances in mathematical equine energetics modelling use a function of the horse’s characteristics and current body condition score to predict their individualized energy requirements [5]. This level of individualized nutrition can help better support the horse, and is built into the fully customized nutrition evaluation Excel Program I developed specifically for Honos Nutrition.
Minimize Grain Feeding
Current diet (and diet management) plays a role in stereotypic behaviour frequency. Cribbing has been found to intensify following grain feeding [4], while weaving peaks prior to grain feeding, especially when the horse has no other food available [6].
Maximize Hay Availability
A study comparing the effect of free-choice and restricted hay in cribbing horses found that cribbers will increase their cribbing frequency by 200% when hay is restricted, compared to when they have free-choice hay available [7].
Incorporate More Grazing/Foraging Opportunities
This study also found that regardless of diet, cribbing horses switch between behaviours ~4x more than normal horses, which is likely why increased grazing opportunities (supplying different forages at once) reduce stereotypic behaviour [8]. It appears that finding different types of forage gives the stereotypic horse another behaviour to switch to (that isn’t the stereotypic behaviour).
Nutritional strategies which drive energy through forage, fat and low-sugar feedstuffs, while providing opportunities for grazing opportunities, can help manage established stereotypic behaviour.
Environmental Changes to Redirect the Behaviour
Horses who crib have been observed to spend around 5 hours a day cribbing [4], which limits their feed intake time and may contribute to a more acidic stomach pH [2]. That said, voluntary hay intake has not been reported to differ between stereotypic and non-stereotypic horses [7]. However, as horses with stereotypies tend to have increased energy expenditures, deflecting this oral behaviour may help the horse gain more functional time back into their day, and help minimize links associated with related health concerns.
Redirect, Not Restrict
Managing environmental factors to redirect rather than physically stop the behaviour is recommended, as rebound behaviour is also observed in horses with stereotypies: horses who were exercised for 20 mins cribbed more following the exercise bout [4]. No difference in learning performance has been found when comparing non-stereotypic horses, cribbers who were allowed to crib, and horses who were not allowed to crib. However, cribbers who were able to crib during the learning phase were less stressed than restricted cribbers AND control horses, suggesting that cribbing is an adaptive, coping function [9]. While methods which physically block the horse from performing the behaviour exist, there is concern about these impairing welfare [8].
Lick Toys
Stall toys that stimulate licking and oral activity tend to lower cribbing rate. Stereotypic horses have increased dopamine transmission, which may drive the increased switching behaviours, so lick toys may give them another mechanism for dopamine release [7]. While investigating the effect of different stall toys on cribbing activity, Whisher et al [4] found that the Likit Tongue Twister toy was the only toy that significantly reduced cribbing.
Contrafreeloading
Contrafreeloading, coined by Glen Jensen in 1963, refers to when an animal has the choice to eat free food or identical food that requires effort, they choose the food they need to work for. This behaviour is self-reinforcing, as it allows them to exhibit natural foraging behaviour. Feeding behaviour has been reported to occupy 50-77% of the free-roaming horse’s time budget [10,11]. Note that feeding behaviour includes foraging - watching your horse graze, you know grazing is tied to movement as they actively seek out the best piece of grass. As such, foraging behaviour constitutes a behavioural need in our horses but is especially important for the stereotypic horse!
Contrafreeloading is commonly integrated into the management of zoo animals to improve welfare by allowing the animal to exhibit a natural behaviour in a duration that more similarly mimics the time spent performing that behaviour in the wild. Different animals have different enrichment duration requirements, with zoologists commonly ranking carnivores, primates and animals with established stereotypes as Very High Priority. Use of multiple feeding stations, forage variation and slow feed devices can help provide the stimulation and foraging opportunities the horse craves.
Social Time
Time spent confined and whether the horse can interact with other horses significantly impacts the development and display of stereotypic behaviours, so time spent on pasture with other horses would provide roughage, exercise and social contact, and may reduce the behaviour [4, 8].
Summary
Supporting the stereotypic horse with nutrition requires identification of individual requirements, meeting these requirements with low-sugar, forage-centred nutrition plans, and using environment changes to redirect, not restrict the behaviour with lick toys, contrafreeloading and social opportunities. Such strategies can help manage the horse while also ensuring their health & happiness is optimized!
REFERENCES
[1]. Carrol, SL., Sykes, BW.,Mills, PC. 2020. An online survey investigating perceived prevalence and treatment options for stereotypic behaviours in horses and undesirable behaviours associated with handling and riding. Equine Veterinary Education 32(S11): 71-81.
[2]. Cooper, JJ., Mcall, N., Johnson, S.Davidson, HPB. 2005. The short-term effects of increasing meal frequency on stereotypic behaviour of stabled horses. Applied Animal Behaviour Science 90(3): 351-364.
[3]. Gill, JC., Lloyd, KE., Bowman, M., Siciliano, PD., Pratt-Phillips, SE. 2017. Relationships Among Digestible Intake, Body Weight and Body Condition in Mature Idle Horses. Journal of Equine Veterinary Science 54 (2017): 32-36.
[4]. Whisher, L., Raum, M., Pina, L., Perez, L., Erb, H., Houpt, C., Houpt, K. 2011. Effects of environmental factors on cribbing activity by horses. Applied Animal Behaviour Science 135(1-2): 63-69.
[5]. Johnson ACB, Biddle AS. 2021. A Standard Scale to Measure Equine Keeper Status and the Effect of Metabolic Tendency on Gut Microbiome Structure. Animals 11: 1975.
[6]. Hothersall, B., Nicol, C. 2009. Role of Diet and Feeding in Normal and Stereotypic Behaviours in Horses. Veterinary Clinics of North America: Equine Practice 25(1): 167-181.
[7]. Moore-Colyer, MJS., Hemmings, A., Hewer, N. 2016. A preliminary investigation into the effect of ad libitum or restricted hay with or without Horslyx on the intake and switching behaviour of normal and crib-biting horses. Livestock Science 186: 59-62.
[8]. Stanley, SO., Cant, JP., Osborne, VR. 2015. A Pilot Study to Determine Whether a Tongue-Activated Liquid Dispenser Would Mitigate Abnormal Behaviour in Pasture-Restricted Horses. Journal of Equine Veterinary Science 35 (11-12): 973-976.
[9]. Freymond, SB., Beuret, S., Ruet, A., Zuberbuhler, K., Bachmann, I., Briefer, EF. 2020. Stereotypic behaviour in horses lowers stress but not spatial learning performance. Applied Animal Behaviour Science 232: 105099.
[10]. Ransom, JI., Cade, BS. 2009. Quantifying Equid Behaviour: A Research Ethogram for Free-Roaming Feral Horses. University of Nebraska-Lincoln: Publications of the US Geological Survey. 26.
[11]. Sigurjónsdóttir, H., Thorhallsdottir, AG., Hafthorsdottir, HM., Granquist, SM. 2012. The Behaviour of Stallions in a Semiferal Herd in Iceland: Time Budgets, Home Ranges and Interactions. International Journal of Zoology 2012(1).
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