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Effects of environmental factors on cribbing activity by horses
Abstract
Quantitative measurements of cribbing were made and the environmental influences on the behavior were examined. Licking the substrate preceded cribbing; the horses licked a median of 1.7 times before each cribbing event while eating grain and 1.1 times before each cribbing event while eating hay. They spent 23% of their time cribbing in bouts separated from other bouts by 30s. Exercise influenced cribbing rate (P<0.013) with a non-significant trend to increase cribbing rate after the longest (20 min) exercise periods. When not exercised the horses cribbed 25.3 +/- 3.8% of the 24-h day; after 20 min exercise they cribbed 30.6 +/- 3.5% of the 24-h day. A stall toy that increased oral activity lowered cribbing rate slightly. The horses cribbed significantly more frequently when fed a sweetened grain diet (29.8 +/- 7.4% of the day) than when fed oats (16 +/- 4.1%). Although no treatment abolished cribbing in these adult horses, modifying diet and increasing foraging behavior with a toy the horse could only lick lowered the time spent cribbing.
... Horses evolved to consume a forage-based diet, with approximately 16-18 hours of the 24-hour time budget used for mastication in the wild , during which 35-40 L of alkaline saliva are produced (Nicol et al., 2002;Moeller et al., 2008;Nagy et al., 2010). Domesticated horses tend to be fed highly palatable cereal-based concentrate feeds to meet high energy requirements (Hemmings et al., 2007;Albright et al., 2009;McBride and Hemmings, 2009;Whisher et al., 2011), which reduce mastication, resulting in decreased saliva production and increased acidity in the foregut (Nicol et al., 2002;Cooper and Albentosa, 2005;Hemmings et al., 2007). This increased acidity may result in gastric discomfort. ...
... Neural changes may also account for the postprandial increase in the crib-biting response. After ingestion of palatable feed, an opioid-mediated release of dopamine within the already sensitized striatum (McBride and Hemmings, 2005;Whisher et al., 2011) correlates with a significantly increased rate of the cribbiting response (Bachmann et al., 2003b;Whisher et al., 2011). ...
... Neural changes may also account for the postprandial increase in the crib-biting response. After ingestion of palatable feed, an opioid-mediated release of dopamine within the already sensitized striatum (McBride and Hemmings, 2005;Whisher et al., 2011) correlates with a significantly increased rate of the cribbiting response (Bachmann et al., 2003b;Whisher et al., 2011). ...
Stereotypic behaviors are commonly observed in domestic equids as they are in a range of captive nondomesticated species. Estimates suggest that 19.5%-32.5% of horses perform a stereotypy. The presence of these behaviors is thought to indicate suboptimal welfare status and can result in secondary physical pathologies, such as colic, ligament strain, and incisor wear. Relatively little is understood about the etiologies of oral and locomotor stereotypies. Seemingly disparate causal factors have been proposed, including gastric pathology, neural adaptation, and genetic predisposition. In this review, we propose a model of causality that presents separate pathways to the development and continuation of oral behaviors such as crib-biting, compared with locomotor alternatives (i.e., weaving). The word stereotypy has alarmingly negative connotation among horse keepers. Stereotypic behaviors are often viewed as vices, and therefore, a number of horse owners and establishments attempt to physically prevent the behavior with harsh mechanical devices. Such interventions can result in chronic stress and be further detrimental to equine welfare. Stereotypy has been proposed to be a stress coping mechanism. However, firm evidence of coping function has proven elusive. This review will explore management options directed at both prophylaxis and remediation.
... Sweet feed is also known to increase the rate of cribbing immediately post-ingestion in established cribbing horses (Kusunose, 1992). Consuming roughage (Gillham et al., 1994) and plain oats (Whisher et al., 2011) does not have the same crib-inducing effect. Some hypothesize that highly palatable diets induce the release of endogenous opioids and, in turn, cribbing through a complex interplay of the opioid, dopaminergic, and glutaminergic neural systems (Dodman et al., 1987;Gillham et al., 1994). ...
... Concentrated feed and, to a lesser extent, sugar solutions were the most robust inducers of cribbing behavior after tasting or ingesting by mouth. As with other cribbing studies, number of cribs was used as the primary indicator of a diet's potency to activate cribbing (Kusunose, 1992;Bachmann et al., 2003;Whisher et al., 2011), and we predicted latency to crib would inversely correlate with this number. However, this relationship is only significant with very strong responses, such as those observed after concentrated grain in both Experiment 1 and 2. Latency to crib showed more variability than number of cribs, especially in the oral ingestion phase Experiment 1, indicating the time to start cribbing may be more subject to influence by external factors such as physical characteristics of the diet or the horse's oral health. ...
... The crib-activation potency of concentrated feed may be associated with its palatability to the horse. The milling process by which concentrated feed is produced presumably creates a diet much more palatable than that of its individual components (Whisher et al., 2011). There was a trend for the sugar and feed solutions to trigger more cribbing than saccharin or tap water when tasted. ...
Concentrated feed diets have been shown to drastically increase the rate of the cribbing, an oral stereotypy in horses, but the specific component causing the rise has not been identified. Furthermore, the mechanism through which feed affects cribbing has not been explored. In the first experiment of this study, we quantified the latency to crib and number of cribs in 15. min after the horses tasted various grain, sugar, and artificial sweetener solutions. Undiluted grain stimulated the most cribs (P< 0.01) compared with all other solutions, and shortest latency to crib, although this was significantly higher only when compared with diluted grain (P = 0.03). In Experiment 2, latency to crib and number of cribs in 15. min after the grain and sugar solutions were administered via nasograstric tube were also evaluated. There were no statistical differences among cribbing responses to grain, fructose, and water administered directly to the stomach although grain stimulated cribbing behavior more quickly than 10% fructose (P = 0.03) and 100% tap water (P = 0.04). These results confirm that highly palatable diets, possibly mediated through the opioid and dopaminergic systems, are one of the most potent inducers of cribbing behavior. The highly palatable taste remains the probable "cribogenic" factor of concentrated diet, although gastric and post-gastric effects cannot be excluded.
... Crib-biting and weaving behaviour, generally increases considerably during the periods of day when concentrates are given (Mills et al., 2002) and this may be linked to stressful feeding times (Hallam et al., 2012). On the other hand, Whisher et al. (2011) found a significantly higher amount of crib-biting occurred during the night compared to day time observations in 8 stereotypic horses. These authors concluded that this was possibly due to a lack of forage available overnight (Whisher et al., 2011). ...
... On the other hand, Whisher et al. (2011) found a significantly higher amount of crib-biting occurred during the night compared to day time observations in 8 stereotypic horses. These authors concluded that this was possibly due to a lack of forage available overnight (Whisher et al., 2011). Therefore, increasing the horse's time spent on feed intake behaviour is an important strategy in management of stabled horses. ...
... Houpt et al. (1986) used point samples every 30 min and Clegg et al. (2008) measured period occurrences using 30 s time samples every 5 min (which only added up to 132 min over a 22 h observation per day). Whisher et al. (2011) also used point samples, although one 'timelapse snapshot' was recorded every minute over 24 h (2 h), giving more detailed results. To the author's knowledge, our study is the only one were continuous measures (in seconds/hour) in stabled horses are presented. ...
The aim of this study was to explore the efficacy of multi-layered haynets and multiple presentation of haynets to increase time spent on feed intake behaviour at night (13. h observation). For preliminary assessment two horses performing the oral stereotypy of crib-biting were included. Six horses received the same amount of forage during a 22-day, cross-over study where treatment consisted of either forage presentation in a single small-holed haynet (SH) or the forage was divided between 3 haynet combinations hung up simultaneously. = multiple haynets (MH). The three haynets presented simultaneously consisted of (a) MH single haynet (same as SH), (b) MH double layered haynet and (c) MH triple layered haynet. Multiple haynets were presented, in random order, on three sides of the stable. Horses were filmed using a video surveillance camera with infrared light source. Behaviour was observed for at least 4 nights per treatment (one night during the acclimatisation period [nights 2-4] and three nights during the end period [nights 7-11]). The observation period commenced at 16.30-17.00. h (point of haynets being presented) until 06.00. h (all horses) or 9.00. h (2 crib-biting horses) the next morning. Data were analysed for normal distribution and ANOVA between haynets, paired t-tests between treatments and Pearson correlation were used (SPSS. 17.00; 2012). There was a significant effect of type of haynet (p<. 0.001) on intake time per kg forage (min/kg for SH: 39; MH all (data combined): 51; MH Single: 27; MH Double: 67; MH Triple: 78; overall sem. 8.9). The overall time budget (minutes per observation hour) showed a significant difference between treatments for eating from haynet, standing still, locomotion and drinking. Horses finished eating from SH haynets at around 01.38. am (±1.05. h s.d.), were last observed at the double net at 03.00. am and at the triple net at 05.12. am (±1.25. h s.d.). Based on these results, providing 6. kg of forage in 3 double-layered, 2.5. cm haynets spread around the stable could potentially lead to an increased feeding time of 2. h per night compared to a single 2.5. cm holed haynet containing 6. kg. From the continuous observation data a clear visual difference in crib-biting pattern and therefore motivation to perform crib-biting emerged between the two stereotypic horses.
... En el mundo, se han realizado varios estudios tendientes a establecer la frecuencia y factores de riesgo asociados a estas estereotipias (3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20). Sin embargo, dentro de los factores de riesgo, el sexo y la edad han mostrado resultados muy contradictorios (1,3,(9)(10)(11)(12)(13)16,(19)(20)(21)(22)(23). No obstante, en ninguno de los estudios realizados los resultados se basaron en información obtenida por observación directa del total de una población determinada, sino que en observación directa de una muestra de una población (13,16,20), o bien en información entregada por los propietarios a través de entrevistas personales o encuestas realizadas a distancia por teléfono, correo o correo electrónico (3)(4)(5)(6)(7)(8)(9)(10)(11)(12)14,15,(17)(18)(19). ...
... Worldwide, several studies have been performed to determine the frequency and risk factors associated with these stereotypies (3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20). However, within the risk factors, sex and age have shown very contradictory results (1,3,(9)(10)(11)(12)(13)16,(19)(20)(21)(22)(23). However, none of the studies' results were based on information obtained from direct observation of an entire determined population, but from direct observation of a sample of a population (13,16,20) or on information provided by the owners through personal interviews or surveys conducted at a distance by telephone, mail or email (3)(4)(5)(6)(7)(8)(9)(10)(11)(12)14,15,(17)(18)(19). ...
... Además, hay factores de riesgo asociados al manejo rutinario en el CHC que pueden estimular el desarrollo de aerofagia tales como: no usar cama de paja (3,20), no tener acceso a potrero (3,8,26), recibir poca cantidad de forraje (3,7,21), recibir una dieta alta en concentrado (3,7,26) y no tener contacto físico con otros caballos (3,15,19,26 (15) señalan que cuando falta contacto visual y físico la prevalencia de aerofagia aumenta al doble (12.3%) al compararla con caballos que tienen acceso a potrero (5.9%), sólo contacto visual (5.9%) o con contacto visual y físico limitado (5.6%), por lo que el estrés asociado al aislamiento podría provocar este aumento (15,19). Respecto a la edad, en coincidencia con resultados del presente estudio, asi como otros estudios señalan que no es un factor de riesgo (3,16,20,21,23 (4,6,8,9,15,20). This high prevalence, and the observed stereotypies in general, could be related to a genetic predisposition (4,10,15) since a prevalence of 30% cribbing has been reported in some families of Thoroughbreds when the average was 2.4 % (4). ...
Objective. To determine the prevalence of classic stereotypies in Thoroughbred racehorses at the Club Hipico Concepcion (CHC) in Chile and its association with sex and age. Materials and methods. The entire population of resident horses at the CHC was studied (n= 341). Each horse trainer (n= 23) was asked for the name, sex and age of the horses under his/her supervision. After that, all the animals were continuously observed inside their stalls for 8 hours by only one person, to record the absence or presence of classic stereotypies (cribbing, weaving, stall-walking). To analyze the data, the animals were divided by sex into 3 groups: stallions, geldings and mares. According to age, they were divided into 2 groups: < 5 years old and 5 years old or more. Descriptive statistics were used and association was tested using the chi square test using p <= 0.05. Results. 13.2% of all CHC's horses displayed stereotypies: cribbing (4.99%), weaving (2.93%) and stall-walking (5.28%). No association was found between the presence of stereotypies and sex or age. Conclusions. Thoroughbred race horses at the CHC showed a high prevalence of classic stereotypies, especially stall-walking.
... Crib-biting is classified as an oral stereotypy in which the horse grasps a fixed object with its incisors, pulls back and emits a characteristic grunt while drawing air into the cranial oesophagus (McGreevy et al., 1995). Crib-biting is a highly motivated behaviour (Houpt, 2012a) and although the aetiology is poorly understood, management Whisher et al., 2011), gastrointestinal function Hothersall and Nicol, 2009) and genetic susceptibility (Vecchiotti and Galanti, 1986) have all been consistently associated with it. Intensively managed horses are often fed large amounts of cereals and concentrated feeds with too little roughage, which has been associated with gastric ulceration (Andrews and Nadeau, 1999;Nicol et al., 2005) and stereotypic behaviour Bachmann et al., 2003;Nicol et al., 2005). ...
... In horses, concentrated feed is assumed to have a reward effect, due to its palatable taste (Ninomiya et al., 2007), and excited and anticipatory behaviour is typically observed before feeding (Peters et al., 2012). Horses have a strong preference for sweet tastes (Thorne et al., 2005) and a significant increase in the rate of crib-biting was found when horses were fed sweetened grain in comparison to unsweetened oats (Gillham et al., 1994;Whisher et al., 2011). In a recent study, we reported that plasma ghrelin concentrations were higher in cribbiting horses than in controls (Hemmann et al., 2012). ...
... Horses are known to crib-bite most intensely shortly after consuming grain or palatable food (Gillham et al., 1994;Whisher et al., 2011), which agreed with our finding that the crib-biting intensity was significantly higher a few minutes after consuming the concentrate than before the concentrate or later after the concentrate. The plasma leptin concentrations were lowest in verified crib-biters in samples taken just before concentrate delivery. ...
Crib-biting in horses is classified as oral stereotypy. A crib-biting horse (Equus caballus) grasps a fixed object with its incisors, pulls back and emits a characteristic grunt while drawing air into the cranial oesophagus. Crib-biting is a highly motivated behaviour but its aetiology is poorly understood. Management, gastrointestinal function and genetic susceptibility have been suggested as causal factors. Leptin and ghrelin are orexogenic hormones that regulate appetite and modulate the reward mechanism.
The aim of this study was to determine ghrelin and leptin plasma concentrations in crib-biting horses. The hypothesis was that ghrelin and leptin are associated with crib-biting. Three plasma samples were collected for plasma leptin and ghrelin assay before and during the first morning feeding in customary environments of 15 horses with stereotypic crib-biting and 15 matched controls. Crib-biting intensity was scored in three 5-min phases, and a subgroup of verified crib-biters (n = 8) was defined as horses that were seen to crib-bite during this study.
Plasma leptin concentrations (mean, 95 % confidence interval, CI) were lower in horses seen to crib-bite (1.2, CI 0.8 - 1.7 and 1.0, CI 0.6-1.7 ng/mL) before and after feeding of concentrate, respectively, than in controls (2.3, CI 1.6 - 3.4 and 2.3, CI 1.6 - 3.4 ng/mL) and correlated negatively with crib-biting intensity. Crib-biting intensity was significantly higher shortly after the concentrate than before or 30 min after it. Plasma ghrelin concentrations were significantly higher before feeding on concentrate than before hay feeding or after concentrate consumption but did not differ between groups.
These findings suggest that leptin is associated with crib-biting behaviour in horses. Lower leptin concentrations in verified crib-biters may be attributable to differences in preferences for palatable food or differences in reward mechanism modulation. Decreased leptin concentration may be a predisposing factor for crib-biting, crib-biting bouts may decrease the leptin concentration, or there may be a third, unknown factor affecting both crib-biting and plasma leptin concentration. In our recent study, plasma ghrelin concentrations were higher in crib-biting horses than in their controls. Both ghrelin and leptin have been associated with feeding, sweet sensitivity and reward behaviour, and thus interaction of leptin and ghrelin with the reward system in feeding behaviour is likely.
... In addition to this specific ball, there are numerous commercial toys that can be placed or hung in the horse's box. Wisher et al. (2011) tested different types of commercial toys and their effect on stereotypical behaviour in horses. The results show that one of the toys, the Tongue Twister ® , significantly reduced crib-biting in horses. ...
... Our results are comparable to findings of previous studies on the use of commercial toys. Wisher et al. (2011) found that horses displayed behaviour towards enrichment items during 1 to 5% of their time. However, since this frequency is not very high, the usefulness of the used items could be questioned. ...
... Vocalisation also occurred less in the presence of the bottle compared to the cases in which an object was absent. Previous work Henderson and Waran, 2001;Wisher et al., 2011) reports contrasting findings regarding the effect of enrichment items on abnormal behaviour. In our study, the rope was found to have a positive effect on licking box fittings, which is considered to be a type of abnormal behaviour (Cooper and McGreevy, 2002): it can possibly reduce the occurrence of licking box fittings. ...
The effect of the provision of simple objects to stabled horses on their behaviour was investigated to determine whether these objects can affect horses’ behaviour in a positive way and thus enrich their environment. A positive influence can for example be measured by a decrease in stereotypical or abnormal activities. In this study, 35 horses were observed in their boxes during three observation periods per observation day. Each observation period lasted one hour and during one hour, each horse was observed 30 times. The observation periods were at noon (11:00–12:00 h), in the afternoon (15:00–16:00 h) and in the evening (20:00–21:00 h). The horses were observed before the objects were provided to set a baseline and then during the presence of the objects. A plastic bottle filled with sand and a rope were chosen as potential enrichment items and placed in a box for one week. For an average of 3.85% (±0.420) of our observations, the horses exhibited behaviour involving the items. This frequency does not significantly reduce after a week. The frequency of item related behaviour was associated with the age and gender of the horse, with a higher frequency in younger horses (P = 0.0151) and in stallions (P = 0.0217). It was also associated with the quantity of hay, with the highest frequency when no hay was available. It is possible that horses are expressing either frustration of having no roughage towards the item or a need for fibres by chewing on the objects. It is suggested that oral activities show the motivation to eat, to attempt to supplement the concentrate feed or the absence of roughage with additional sources of fibres. The use of the items had the tendency to reduce one specific type of abnormal behaviour, i.e. the occurrence of licking walls and other objects (P = 0.0586). However, it is possible that horses redirect their abnormal behaviour towards the items. Biting behaviour was associated with the quantity of hay, with a higher frequency when no hay was available. This possibly also suggests a search for other sources of fibres when roughage is absent. Although horses exhibited item related behaviour, the used objects do not offer a food reward and arouse the interest only to a very limited extent, showing a limited enriching effect.
... Crib-biting is classified as an oral stereotypy in which the horse grasps a fixed object with its incisors, pulls back and emits a characteristic grunt while drawing air into the cranial oesophagus (McGreevy et al., 1995). Crib-biting is a highly motivated behaviour (Houpt, 2012a) and although the aetiology is poorly understood, management Whisher et al., 2011), gastrointestinal function Hothersall and Nicol, 2009) and genetic susceptibility (Vecchiotti and Galanti, 1986) have all been consistently associated with it. Intensively managed horses are often fed large amounts of cereals and concentrated feeds with too little roughage, which has been associated with gastric ulceration (Andrews and Nadeau, 1999;Nicol et al., 2005) and stereotypic behaviour Bachmann et al., 2003;Nicol et al., 2005). ...
... In horses, concentrated feed is assumed to have a reward effect, due to its palatable taste (Ninomiya et al., 2007), and excited and anticipatory behaviour is typically observed before feeding (Peters et al., 2012). Horses have a strong preference for sweet tastes (Thorne et al., 2005) and a significant increase in the rate of crib-biting was found when horses were fed sweetened grain in comparison to unsweetened oats (Gillham et al., 1994;Whisher et al., 2011). In a recent study, we reported that plasma ghrelin concentrations were higher in cribbiting horses than in controls (Hemmann et al., 2012). ...
... Horses are known to crib-bite most intensely shortly after consuming grain or palatable food (Gillham et al., 1994;Whisher et al., 2011), which agreed with our finding that the crib-biting intensity was significantly higher a few minutes after consuming the concentrate than before the concentrate or later after the concentrate. The plasma leptin concentrations were lowest in verified crib-biters in samples taken just before concentrate delivery. ...
The reason why some horses begin an oral stereotypy such as crib-biting is not known. The aim of this study was to measure ghrelin and leptin concentrations in plasma concentrations to determine whether there is a link to crib-biting in horses. Plasma samples (n=3) were collected for plasma leptin and ghrelin assay before and during the morning first feeding in the usual environments of 15 horses with stereotypic crib-biting and 15 matched controls. The crib-biting intensity was scored in three 5-min phases, and a subgroup of verified crib-biters (n=8) was defined as horses that were seen to crib-bite during this study. Plasma leptin concentration (mean and 95% confidence interval [CI]) was lower in horses observed to crib-bite before and after feeding of concentrates (1.2, CI 0.8-1.7ng/mL and 1.0, CI 0.6-1.7) than in non-crib-biters (2.3, CI 1.6-3.4 and 2.3, CI 1.6-3.4ng/mL, respectively) and correlated negatively with crib-biting intensity. Crib-biting intensity was significantly higher shortly after feeding than before or 30min later. Plasma ghrelin concentration was significantly higher before feeding concentrate than before hay feeding or after the concentrate, but did not differ between groups. There was a significant negative correlation between body composition score and plasma ghrelin concentration. These findings suggest that leptin concentrations may be associated with crib-biting behaviour in horses.
... Horses trained with the join up method did not especially follow their trainer when in pasture (Krueger, 2007) and cribbing increased after a 20 minutes forced exercise in the round pen in Whisher et al. (2011)'s study. The reaction of horses towards humans after training with a conventional versus a "sympathetic" method during a human-horse approach test did not differ statistically (Visser et al., 2009). ...
... Only one study indicates that horses prefer to look at their trainer with the left eye (Farmer et al., 2010) generally associated with a negatively connoted situation (Austin and Rogers, 2014;Larose et al., 2006). However, although the authors consider that the trainers were positively connoted, ensuring the care and feeding of the horses, they were training the horses through a join up technique which, as mentioned earlier, does not seem to favour the relationship, and may even be associated with an increase of undesirable behaviors (Whisher et al., 2011). ...
Research in cognitive psychology has repeatedly shown how much cognition and emotions are mutually related to one another. Psychological disorders are associated with cognitive (attention, memory and judgment) biases and chronic pain may affect attention, learning or memory. Laboratory studies have provided useful insights about the processes involved but observations about spontaneous animal models, living in different stress/welfare conditions may help understand further how cognition and welfare are interrelated in the « real world ». Domestic horses constitute such a model as they live in a variety of conditions that impact differently their welfare state. In the present review, we try and provide an overview of the scientific literature on cognition and welfare of domestic horses and their interrelationship. We address how emotions and welfare may affect cognitive processes in horses and impact the way they perceive their environment (including work). We propose new methods for assessing the relationship between welfare and cognition and open up the discussion on the evolution of the brain and the part domestication may have played.
... However, it has been confirmed that more intensive training does not decrease the crib biting development. In fact, the frequency increases with increased training time, particularly because the horses might be nervous and stressed after strenuous exercise (Whisher et al. 2011). This fact could influence the surgical success rate as well, especially if the change of training was too radical. ...
... According to some authors, stable toy application reinforces development of crib biting because, in the majority of cases, toys filled with sweet treats are used (Marsden 2008). Toys seem to be ineffective as the horses spend only 1-5% of time playing with them and because the digestion of sugar potentiates the horse to develop cribbing behaviour (Whisher et al. 2011). ...
The objective of this retrospective study was to assess the success rate of Forssell’s modified myectomy-surgical treatment of crib biting on 33 horses of various breeds identified as stereotypical cribbers which were referred to the Equine Clinic in Brno between January 2001 and December 2010. The long term outcome was available for all horses. The overall success of the surgery without considering influencing factors was 61%. Thirteen horses (39%) returned to the stereotypical behaviour sooner or later after the surgery. In this retrospective study we confirmed the dependence of success of the surgery on the necessity of early treatment of the problem (up to 6 months after the appearance of initial signs), with the significance level of P = 0.037. Any connection between age, breed or sex, and positive outcome of the surgery were not confirmed during statistical evaluation. When the horses were diagnosed early enough, an 80% success rate in surgical treatment performed within 6 months from the initial signs of crib biting was recorded, which seems to be very promising. It can be concluded that surgical treatment of crib biting by modified Forsell’s myectomy is the recommended option in the therapy of this oral stereotype. © 2015, University of Veterinary and Pharmaceutical Sciences. All rights reserved.
... The display of stereotypies has been shown to be related to the lack of control that an animal has over its environment [3][4][5]. Animals in such situations are predisposed to develop a variety of stress-related diseases [6][7][8][9]. ...
... The expression of abnormal behaviours such as crib-biting, wind sucking or repetitive licking leaves distinctive marks on animal enclosures [8,9] (figure 1). These marks may accumulate over time and provide insight into the well-being of the individual that made them, providing the basis for a rapid welfare assessment approach. ...
The welfare of an individual depends on its capacity to overcome suboptimal conditions in its environment; otherwise, its physical and psychological health becomes compromised. A situation that clearly indicates lack of control of the environment is the expression of abnormal behaviours, such as stereotypies. This study aimed to verify the well-being of police horses using a new rapid form of welfare assessment: an archaeological approach. To this end, we sampled and quantified marks found on the stables, deposited as a result of abnormal behaviour. We cross-referenced these physical marks with veterinary records of diseases, such as colic, known to be associated with stress. A total of 46 horses were sampled and the results showed a significant medium-strength, positive correlation between bite mark frequency on stable doors and the incidence of colic. A weak significant positive correlation was found between length of scratch marks (from pawing) and the incidence of lameness. We conclude that these marks reflect the accumulated expression of abnormal behaviour and can provide rapid insight into the welfare of individual animals.
... In the absence of an appropriate food-related stimulus, an animal is unable to complete the sequence of foraging behavior, thereby causing the movement bouts to become shorter, repetitive, and rigid over time, as seen in the oral stereotypy [ 4 , 5 ]. Environmental stressors such as nutrient restriction and inappropriate feeding strategies that limit foraging and food manipulation were major contributors to the development of oral stereotypy and redirected behaviors [6][7][8][9] . Stereotypies have been proposed as animals' coping strategies for long-term exposure to stressful living conditions. ...
The high prevalence of abnormal oral behaviour (AOB) in working horses has been linked to management issues and the pathophysiology of this behaviour remains unclear. Therefore, this study aims to elucidate the blood profile, hormones, and telomere length responses between low and high levels of AOB among different horse working groups. A total of 207 healthy horses from various breeds were initially selected from four working groups (leisure riding, equestrian, endurance, and patrolling) and observed for the time spent on AOB. Then, six horses each with higher and lower AOB than the population means were randomly selected from each of the working groups and categorized as high and low AOB horses, respectively. Blood samples were collected for haematology, biochemistry, cortisol, ghrelin, leptin, and relative telomere length analyses. High AOB horses notably had higher values of glucose, alanine aminotransferase (ALT), alkaline phosphatase (ALP), and creatine kinase (CK) compared to low AOB horses. High AOB horses also recorded higher plasma cortisol and ghrelin, but lower leptin concentrations. Among working groups, both endurance and patrolling horses presented the highest values in sodium, potassium, chloride, phosphate, ALT, and CK. While patrolling horses had the lowest levels of urea, ALP, and albumin levels, equestrian and leisure horses recorded the highest and lowest plasma cortisol and leptin concentrations, respectively. Finally, the telomere length of endurance and patrolling horses were significantly greater than leisure and equestrian horses. The present findings suggest that AOB horses had distinctive physiological characteristics that could be linked to improper diet and a demanding workload, while ghrelin and leptin hormones could be potential biomarkers for this behaviour.
... Keeping a horse occupied during separation reduces the opportunity for challenging behaviors (Henderson & Waran, 2001). Indeed, environmental enrichment in the form of visual stimuli (e.g., mirrors; McAfee et al., 2002;high-resolution photographs;Cooper et al., 2000), or toys (e.g., hanging toys or inflatable balls; Whisher et al., 2011;Equiballs;Henderson & Waran, 2001), which evoke non-challenging behaviors, has been shown to reduce stereotypy in horses. Training alternative behaviors has been successful in reducing challenging behaviors occurring during float loading (Ferguson & Rosales-Ruiz, 2001;Hendriksen et al., 2011;Slater & Dymond, 2011). ...
Equidae are herd animals, yet domesticated horses are routinely separated from their conspecifics. Separation of horses that are strongly bonded to one another can result in separation-induced challenging behaviors including human- and object-directed aggression, motor agitation, and stereotypy. There is a paucity of evidence-based strategies to control separation-induced problem behavior in domesticated horses. The current study used target training as an incompatible-behavior strategy to decrease separation-induced challenging behaviors. Four horses with a history of separation-induced challenging behaviors were clicker and target trained. Participants underwent a multiple-baseline experimental design across horse-owner dyads. The multiple-baseline design is a time-series approach based on the randomization of the treatment inception timepoint that can demonstrate treatment effects with small sample sizes. Horses underwent separation trials while being required to touch a target upon verbal commands. Compliance was reinforced with clicks paired with small portions of high-preference edibles. The intervention decreased separation-induced challenging behaviors in all horses to near-zero levels. In order to facilitate the uptake of treatment gains, owners participated in a brief owner training protocol during the generalization phase of the study. While the field has traditionally relied on aversive control, the effectiveness of the current intervention supports a wider application of reinforcement-based strategies in equine training.
... Exercise includes both free movement (e.g., paddock) and work (e.g., lunging and riding), whereas much evidence shows that free exercise has a very different effect on horse welfare from working exercise and is actively chosen by horses when given the opportunity [56,57]. Whisher et al. [58] have shown that cribbing may increase with increasing working time, whereas stereotypic behaviors overall diminish when horses have access to free exercise (e.g., [59]). ...
Although the question of animal welfare has been an important source of concern in the scientific community for several decades, many aspects are still under debate. On-farm assessments have to be rapid, acceptable to farmers and safe for both the assessors and animals. They are thus very demanding, with multiple decisions to make, such as the choice of appropriate indicators, sampling methods and scoring. Research has moved from resource-based to animal-based criteria, which reflects the subjective welfare state of an animal rather than relying upon external indices. In the present review, we describe two major (i.e., the most frequently/recently tested or disseminated) protocols: one in low-/middle-income countries, and the other in high-income countries, for on-farm assessments of horses, using animal-based resources; we evaluate their strengths and limitations, and then we compare their results with those obtained by various other studies. We propose lines of improvement, particularly in view of public dissemination, and offer suggestions for further refinement or new protocols. We emphasize the high risks of putting the cart before the horse, i.e., proposing protocols that rely upon indicators and sampling methods that need to be refined, as this could lead to under-evaluation (or less likely over-evaluation) of current welfare problems. Because welfare is a subjective experience, the true representation of an individual’s actual welfare status has to be evaluated by using objective assessment tools (that are validated and have a scientific basis) used by well-trained observers.
... As for crib-biting, the prevalence found is within the range reported by previous studies (9,11,(20)(21)(22)24,(27)(28)(29)32,33,(36)(37)(38)(39)(40)(41)(42)(43)(44)(45)(46)(47)(48)(49)(50)(51)(52)(53)(54)61), which can reach up to 13.3% (60), although a higher prevalence was expected due to wood shavings as bedding (22)(23)(24)(25), concentrate feeding (28,30,62), no grazing (17,24,25) and consumption of less than 6.8 kg of hay feed 3 times a day (23). The failure to find a link between gender and crib-biting had already been reported in another study (17,28,43,50,51,53,54). ...
The objectives of this study were to evaluate the prevalence of crib-biting and weaving in horses stabled in tie stalls and to investigate the relationship between gender, age, and stereotypies. One hundred and seventy-seven half-bred saddle horse residents of a riding school, of both genders and between the ages of 3 and 20, distributed in three buildings with the same management conditions, were observed. For the statistical analysis according to gender, the horses were classified into 2 groups: geldings (n = 110) and mares (n = 67). According to age, the horses were classified into 2 groups: namely, 3 to 7 years old (n = 31) and 8 to 20 years old (n = 146). During three consecutive days, a single evaluator spent one day per building observing the presence or absence of crib-biting and weaving. Each given day was divided into 2 periods of observation: from 7:30 to 13:00 and from 14:30 to 20:00. Stereotypies were observed in 4.5% of the horses, i.e., 3.4% of the horses showed crib-biting and 1.1% showed weaving. We did not find horses showing crib-biting and weaving at the same time. No association was found between the prevalence of stereotypies and either gender or age of the horses. Our results suggest that visual and tactile contact with other horses, which occurs in tie-stall housing, could reduce the risk of developing weaving in tie-stall horses but not crib-biting.
... The challenge in applying the results of these studies to the relationship between walking and zoo elephant welfare is that they evaluated human-led exercise, which could have different associations with welfare than self-directed exercise. Human-led exercise sessions were associated with an increase in the performance of stereotypic behavior in horses [22]. In preference tests, horses reliably chose to remain in their stalls rather than participate in human-led exercise [23], but also preferred voluntary exercise (via release into a large paddock) over remaining in their stall [23]. ...
Research with humans and other animals suggests that walking benefits physical health. Perhaps because these links have been demonstrated in other species, it has been suggested that walking is important to elephant welfare, and that zoo elephant exhibits should be designed to allow for more walking. Our study is the first to address this suggestion empirically by measuring the mean daily walking distance of elephants in North American zoos, determining the factors that are associated with variations in walking distance, and testing for associations between walking and welfare indicators. We used anklets equipped with GPS data loggers to measure outdoor daily walking distance in 56 adult female African (n = 33) and Asian (n = 23) elephants housed in 30 North American zoos. We collected 259 days of data and determined associations between distance walked and social, housing, management, and demographic factors. Elephants walked an average of 5.3 km/day with no significant difference between species. In our multivariable model, more diverse feeding regimens were correlated with increased walking, and elephants who were fed on a temporally unpredictable feeding schedule walked 1.29 km/day more than elephants fed on a predictable schedule. Distance walked was also positively correlated with an increase in the number of social groupings and negatively correlated with age. We found a small but significant negative correlation between distance walked and nighttime Space Experience, but no other associations between walking distances and exhibit size were found. Finally, distance walked was not related to health or behavioral outcomes including foot health, joint health, body condition, and the performance of stereotypic behavior, suggesting that more research is necessary to determine explicitly how differences in walking may impact elephant welfare.
... During enrichment, stereotypic behaviors were significantly reduced when using the Equiball [10]. Whisher et al. [11] compared multiple food puzzles and found that only the tongue twister reduced cribbing significantly. Noncommercial items, such as a ball, rope, or pylon, all have elicited a significant change in behavior in both nonstereotypic and stereotypic horses [12]. ...
Stereotypic behavior in horses, including cribbing and weaving, can be attributed to a number of different factors including the number of hours in a stall, number of grazing opportunities, number of times fed hay in a day, and the ability to touch other horses. By providing environmental enrichment that allows for feed availability for a longer time period, a reduction of stereotypic behaviors could be seen. A behavioral tool, a tongue-activated liquid dispenser, was tested to determine whether the device itself could reduce stereotypic behaviors. Four horses, two weavers and two cribbers were studied over a 4-day period. Each horse acted as it's own control in a randomized block design. On average, data trended toward a treatment effect depending on the day.
... Esto coincide con lo reportado por Mills et al. (2002), quienes en FSC encontraron que el 16,4% de los caballos de dos años presentaban alguna estereotipia, porcentaje que disminuía drásticamente hasta los 6 años, y que era explicado como consecuencia de la venta asociada a la disminución del rendimiento de estos caballos. También en relación con la aerofagia y en concordancia con nuestros resultados, otros estudios señalan que la edad no sería un factor de riesgo (McGreevy et al., 1995a;Christie et al., 2006;Muñoz et al., 2009;Whisher et al., 2011), sin embargo Luescher et al. (1998) señalan que la frecuencia de aerofagia aumenta con la edad. ...
RESUMEN Estereotipias clásicas en caballos, como aerofagia, balanceo y caminar en pesebrera, son indicado-res del bienestar animal actual o pasado. El objetivo de este estudio fue determinar la prevalencia de estereotipias clásicas en caballos de salto de la región del Biobío, Chile, y su asociación con el sexo y edad. Se estudiaron todos los caballos de salto (n = 98) residentes en los seis clubes ecuestres de la Región. A cada cuidador se le consultó nombre, sexo y edad de cada caballo a su cargo. Luego, para detectar la presencia o ausencia de estereotipias clásicas, durante los primeros 20 minutos de cada hora, por 8 horas, una sola persona observó directamente los caballos mientras se encontraban en su pesebrera. Los caballos fueron divididos por sexo en tres grupos: machos enteros, machos castrados y hembras. De acuerdo a la edad se dividieron en dos grupos: 3 a 7 años, y 8 a 20 años. Los resultados en la parte descriptiva se expresan como porcentajes simples. Para el análisis estadístico de las variables sexo y edad, se utilizó la prueba exacta de Fisher, con un nivel de significancia de p < 0,05. El 7,14% de los caballos de salto presentaban estereotipias: aerofagia (6,12%), caminar en pesebrera (1,02%), ninguno realizaba balanceo. En relación al sexo, sólo se encontró asociación estadísticamente signi-ficativa con la presencia de aerofagia, siendo más probable su presencia en machos castrados que en hembras. No se encontró asociación entre la presencia de estereotipias y la edad. Palabras clave: comportamiento estereotipado, aerofagia, balanceo, caminar en pesebrera, equinos. ABSTRACT Common stereotypies in horses, such as cribbing, weaving and stall walking, are indicators of current or past animal welfare. The objective of this study was to determine the prevalence of classic stereotypes in show jumping horses of Region of Biobío, Chile, and its association with sex and age. The entire population of resident horses (n = 98) in the 6 equestrian clubs of Region was studied. Each horse trainer was asked to provide the name, sex and age of the horses under his/her supervision. In order to record the presence or absence of common stereotypies, horses were under the observation of only one person in their stalls during the first 20 minutes of each hour for 8 hours. To analyze the data, horses were divided by sex into 3 groups: stallions, geldings and mares. Based on their age, they were divided into 2 groups: 3 to 7 years and 8 to 20 years. Results are expressed as percentages. Fisher's exact test with p < 0.05 was used for the statistical analysis of both variables. A 7.14% of all show jumping horses presented stereotypies: cribbing (6.12%) and stall walking (1.02%), but no weaving was observed. With respect to sex, there was only one statistically significant rela
... Other strategies for environmental enrichment include provision of visual stimuli such as outdoor vistas or mirrors 51 and high-resolution photographs, which can satisfy a horse's natural compulsion to see other animals and visual horizons 52 . Non-edible toys may be used, but adult horses are unlikely to use hanging toys or large inflatable balls 53 . There is currently little scientific evidence to indicate which enrichment methods are most effective for horses 46 . ...
Horses and ponies are used for experimental research in a variety of fields, but there is little published scientific literature that describes current or evidence-based recommendations for keeping and managing these species for research purposes. Equine species require particular environmental conditions and allowances to accommodate their behavior and physiology. Here the authors review studies and common practices for ambient facility conditions; provision of bedding, food and water; opportunities for exercise and environmental enrichment; allocation of facility spaces and resources; and design and management of different stabling systems for horses and ponies in research. Careful consideration of these factors can help to improve the welfare of equine subjects in research and to ensure high-quality experimental data.
... This behavior occurs in about 5%-10% of domesticated horses (Houpt, 2012). This behavior is characterized by the horse appearing to bite a flat surface (such as a stable door), pulling the head back, and taking air in (Clegg et al., 2008;Cooper and McGreevy, 2007;Whisher et al., 2011). Crib biting may cause the loss of body condition, tooth wear, wind sucking (another similar equine stereotypy), colic (McBride and Hemmings, 2009), and a risk of temporohyoid osteoarthritis (Houpt, 2012). ...
... This may be a factor of these breeds having been bred for high performance and the high stresses that these breeds encounter in their competition life. Also, it could be the result of longer exercise periods in Thoroughbred horses compared with other breeds (Whisher et al. 2011). White and dun were more common colors, which showed SB. ...
This study was undertaken to investigate factors associated with stereotypic behavior in stabled horses in Iran. We evaluated sex, age, breed, color, frequency of feeding in the day, social contact with other horses during stabling, and the design of stable. We divided the stable design into two groups: indoor stables and those where the horses had contact with the outside environment. No statistical relationship could be found between the factors examined and stereotypic behavior. However, we found trends relating age group (1–7 and >7 years), color (white and dun were over-represented), breed (Thoroughbred and Arabian horses were over-represented), and daily feeding frequency (twice over-represented compared with three times). Horses with tactile contact with others showed less stereotypy than those that had no tactile contact with neighbors. This study suggested that the most important factors in the occurrence of stereotypic behavior are social interaction with other horses and frequency of feeding. Stereotypies appear to be related to management factors.
... On the day of the week that the horses were not exercised they did not exhibit a PM increase in pawing. Exercise decreases one equine behavior−wood chewing [3] but increases another−crib biting [9]. Horses may be pawing to create holes in which they may place their back legs to redistribute their weight or compensate for unevenness of flooring. ...
The objectives of this study were to determine the prevalence of pawing behavior in a population of Standardbred racehorses and
the relationship of pawing frequency to time of day. Standardbreds (n=41) were observed using instantaneous scan sampling twice
daily, in the morning before training and in the afternoon after training. A majority of the horses, twenty-four (58.5%) of the 41
horses showed pawing behavior at least once (median=7, interquartile range=2–15). After training, there were a median of 4
(interquartile range 1–11) observations of pawing or 11.2% of total observations. In the morning, before training, there were 3
(0–3.25) pawing observations, or 9.1% of total observations. There was a significantly greater frequency of pawing in the
afternoon (P=0.0005). They pawed less on Sunday afternoons when they had not trained. Pawing may be related to exercise and,
possibly, discomfort.
... It has been shown that time spent for feeding was negatively correlated with time spent performing stereotypic behaviors (Marsden, 2002;Henderson, 2007;Wickens and Heleski, 2010). The prolongation of chewing behavior may be an important factor to reduce the crib biting behavior (Whisher et al., 2011). A foraging device named "Equiball" has been suggested as an environmental enrichment tool that reduces performance of stereotypic behaviors by means of increasing feeding time (Henderson and Waran, 2001). ...
There are strong suggestions that equine stereotypies are connected to poor welfare and a suboptimal management and/or stabling environment. Different forms of equine stereotypic behaviors have been described. Crib biting, weaving, and box walking are considered the most prevalent. Several studies have been conducted to establish links between the underlying causes and potential function of such behaviors. Both experimental and epidemiological studies have indicated management factors specifically feeding practices, housing conditions, and weaning method as crucial in the development of stereotypies in stabled horses. Some neurological studies on equine stereotypy demonstrated some forms of central nervous system dysfunction as being associated with the performance of stereotypic behaviors. Different researchers hypothesized that the functional significance of stereotypies is that they reduce stress in captive environments and should thus be considered as a coping mechanism. In contrast, the owner's perspective is often that a stereotypic horse has a “stable vice” that needs to be stopped, and different kinds of methods have been developed to control or regulate stereotypic behaviors. However, if the stress-reducing hypothesis is correct, controlling stereotypic behaviors particularly by physical and surgical approaches without addressing the underlying causes is of great concern to the horse's welfare. Although there is ongoing uncertainty about the exact function, the growing knowledge about causation should be applied: under all circumstances prevention is better than cure.
... Kusunose [22] showed CB frequency to be low around the time of roughage meal delivery, and Redbo et al [20] found the risk of stereotypic behavior, including CB, to be reduced when the amount of roughage is increased. CB activity in the present study was similar however to the occurrence of CB behavior observed by Whisher et al [27]. ...
It was hypothesized that horses exhibiting crib-biting (CB) have a greater degree of gastric mucosal damage and higher serum gastrin response to concentrate feeding than non-crib-biting (NCB) horses. Eighteen mature horses, 9 CB and 9 NCB, were used to determine prevalence and severity of gastric mucosal damage and effect of concentrate feeding on circulating gastrin. Horses were maintained on pasture with free access to hay and fed a pelleted concentrate diet twice daily. Number of crib-bites and duration of cribbing bouts were recorded in a 24-hour period. Endoscopic examinations (EE) of the squamous mucosa were performed and gastric fluid sampled after 24 to 28 hour feed removal. Following EE, horses were returned to pasture for 72 hours. Blood was collected following 12-hour feed removal (0 minutes), and at 60 and 120 minutes after consuming 1 kg of concentrate. Mean number of crib bites in 24 hours was 1,558 ± 303 with CB peaking prior to and during the afternoon feeding (3:30 PM, P < .05). There were no differences in the number or severity of ulcers, prevalence of hyperkeratosis, or baseline gastric pH between CB and NCB. Serum gastrin concentration at 60 and 120 minutes was greater (P < .05) and tended to be greater (P < .06), respectively, in CB than in NCB horses following feeding of concentrate. Crib-biting behavior in horses maintained on pasture was not associated with gastric mucosal damage; however, consumption of concentrate feed resulted in greater serum gastrin concentration in CB horses.
Chilean horse has been a breed of closed registry for more than 85 years. Crib-biting is an oral stereotypy with a history of genetic predisposition that affects the Chilean horse. This study was aimed to estimate the heritability of crib-biting in Chilean horses. Data were collected from a total of 2,098 Chilean horses registered in the Agricultural National Society Stud Book, which have been stabled for at least one year during their life. Horse owners provided for: name of the horse, name of the breeding farm, number of registration in the Agricultural National Society Stud Book, year of birth, gender (male or female), years of stabling and whether or not the horse presented crib-biting. Web way, the online Agricultural National Society Stud Book was accessed to create a database with information of the name and registration numbers of the sire and dam of each horse (n=2,098). Additionally, antecedents for all the ancestors available in the Chilean Horse Stud Book for all crib-biters (n=84) were included, as well as a random sample of non-crib-biters (n=215). The genealogical database was made up by a total of 7,187 individuals with the average inbreeding coefficient of 1.63%. The prevalence of crib-biting was 4%, being more frequent in males (P<0.0001). The heritability of crib-biting found in the present study (h²=0.229±0.058) suggest that this is a hereditary condition that follows a quantitative model of inheritance, where the influence of additive genetic factors is moderate to low.
This review focuses on associations of cortisol and the hormone ghrelin on abnormal oral behaviours, predominantly stereotypic behaviour, in horses. Abnormal oral behaviours are prevalent in the stabled horse population. Feeding practice and satiety seem to play a significant role in the development of the behaviours. The effect of macronutrients on the occurrence of abnormal oral behaviours and satiety remain to be elucidated in horses. Ghrelin, known as the hunger hormone, is produced by the ghrelinergic cells in the gastrointestinal tract. Ghrelin is found to be involved in various physiological processes such as stress, eating disorders and food selection. Feed preference in horses is chiefly controlled by their ability to distinguish macronutrients in the food, so the novel approach of the use of ghrelin to tackle the problem in the abnormal oral behaviours may provide promising findings in future research into the occurrence and management of equine stereotypies.
This study aimed to determine the prevalence of classic stereotypies in thoroughbred race horses at the Hipódromo Chile (Chile) and the influence of gender and age. All population of thoroughbred racing horses resident at the Hipódromo Chile was studied (n = 565). Direct observation determined the presence or absence of cribbing, stall-walking, or weaving in each horse. Results are expressed as simple percentages. For statistical analysis, Fisher's exact test was used with a significance level of p < 0.05. The overall prevalence of classic stereotypies was 6.19% (aerophagia 2.68%, stall-circling 2.33%, and weaving 1.79%). No association was found between stereotypies and gender. Association was only found between the presence of stall-circling and 2 to 3-year-old horses (p = 0.022). Results suggest that thoroughbred race horses at the Hipódromo Chile have a prevalence of classic stereotypies within the previously established range and that age is a risk factor for stall-circling.
Development and continued performance of stereotypic behavior have been linked to suboptimal environments. The performance of stereotypic behavior has been used as an indicator of poor welfare although it is often difficult to determine whether behavior is result of poor welfare in past or due to current adverse conditions. Crib-biting and weaving behavior are two of most widely recognized equine stereotypies. Crib-biting is an example of an oral stereotypic behavior in which horse anchors its top incisor teeth on fixed object, pulls backward, contracting the neck muscles, and draws air into the cranial esophagus emitting an audible grunt. Weaving is a locomotor stereotypic behavior pattern characterized by a lateral swaying movement in which head, neck, forequarters, and sometimes hindquarters are engaged. Crib-biting, weaving, and other stereotypic behaviors are recognized as both a management and a welfare concern, and many owners attempt to physically prevent horses from engaging in these behaviors.
Reasons for performing study:
Crib-biting is a common oral stereotypy. Although most treatments involve prevention, the efficacy of various anti-crib devices, including surgically implanted gingival rings, has thus far not been empirically tested.
Objectives:
Demonstrate the effect that 2 anti-crib collars, muzzle, and gingival rings have on crib-biting, other maintenance behaviours, and cortisol levels in established crib-biting horses.
Study design:
Randomised, crossover clinical trial.
Methods:
In experiment I, 2 anti-crib collars and a muzzle were used on 8 established crib-biting horses; horses wore each of 3 devices for 7 days, with a 7-day device-free period between treatments. Horses were video recorded for 24 h at least 3 times each week prior to any device placement, and always the day after a device was removed. In experiment II, gingival rings were used in 6 established crib-biting horses; horses were video recorded for 3 days prior to ring implantation and the day after surgery until the rings became ineffective. Plasma cortisol levels were assessed every day during experiment II and on Days 1, 3, and 5 of each week during experiment I.
Results:
All devices significantly reduced crib-biting compared to control periods. There was no significant difference in crib-bite reduction amongst devices in experiment I, or between pre-device periods and the first day the device was removed. The only increase in plasma cortisol occurred on the day of surgery in experiment II.
Conclusions:
Common anti-crib devices are effective in reducing crib-biting and significant distress was not evident from our findings. We did not find a post-inhibitory rebound effect. Surgical rings were successful only temporarily and implantation was likely painful to the horses. Because stereotypies involve suboptimal environmental conditions, efforts should be made to improve husbandry factors previously shown to contribute to crib-biting, and research into decreasing horses' motivation to crib-bite should continue. This article is protected by copyright. All rights reserved.
A preliminary study involving riding school horses and 2 nonedible items, a Jolly Ball and a rope, was carried out to explore the long-term (2 weeks) interest of horses in these items. Twelve horses were observed in their stalls during 3 observation periods per observation day (10 AM-11 AM; 11 AM-12 PM; 6 PM-7 PM) using the scan sampling method. Each object was presented to each horse for 2 weeks and observations were carried out on Saturday and Sunday after introduction (weekend 1), after 1 week (weekend 2), and after 2 weeks (weekend 3). Both items were hung up on the front wall of the stall. Items were presented to the horses in a rotation system so that each horse was exposed to each condition (ball, rope, control). Item-related behavior occurred to a limited extent, possibly due to the presence of sufficient hay quantities. The available bedding material also influenced the use of the items, as horses showed more item-related behavior when bedding material was unclean. The fact that both items were hung may also have played a role. Both objects were equally interesting but the ball maintained the horse's interest over a longer period. In the presence of the rope, however, no item-related behavior was seen at the end of the second week. There was no effect observed on general activities or on abnormal behavior. This finding might be due to the patterns of abnormal oral behavior (licking and manipulating box fittings) that the horses exhibited and the fact that the objects did not address the underlying causes of this behavior. When horses are appropriately reared, nonedible items are not useful as enrichment. In this study, balls seemed to maintain interest over a longer period. To explore the potential for long-term interest in nonedible items further, a more extensive study with a larger sample size and continuous behavior recording is recommended. The way of providing items should also be taken into account.
The motivation to crib was compared to the motivation to eat. Eight horses (Equus caballus) were operantly conditioned to push a switch for the opportunity to crib. When a progressive ratio was imposed, they worked as hard for a cribbing opportunity as for the opportunity to
eat sweetened grain indicating a high demand. Another measure of motivation is the effort expended by the animal. The force exerted when a horse cribs was measured by attaching weights to a door and observing how heavy the weights had to be to prevent the horse from pulling a door toward itself
when it cribbed. Seven horses were tested. Each neck flex of a crib-biting action was forceful enough to lift 29.4 (± 5) kg. The motivation to crib and the force involved indicates that thwarting cribbing is a welfare issue.
It has been hypothesized that cribbing, the equine oral stereotypy, may increase salivary production and, therefore, reduce gastric acidity in a species prone to gastric ulcers. To test the hypothesis that cribbing stimulates salivary secretion, parotid salivary duct fistulas were surgically created in 2 horses. In the first experiment, saliva was collected while the number of crib bites was counted. There was no significant relation (r2 = 0.022) between the numbers of crib bites and the volume of saliva produced. The second experiment involved measuring salivary output when one horse was cribbing and when he was eating, but could not crib. Before feeding, the horse produced 1 (0-2) mL of saliva while displaying 20 crib bites. The horse produced 31 (2-212) mL of saliva while eating 200 g of grain. After eating, the horse produced 2 (1-10) mL of saliva while displaying 20 crib bites. There was a significant difference in saliva production associated with eating (Kruskal–Wallis statistic = 12.42, P < 0.02). Fifteen to 30 times more saliva was produced while eating than while cribbing. These preliminary findings indicate that in those 2 cribbing horses, saliva production was not increased during cribbing, thereby questioning the hypothesis that saliva production during cribbing leads to decrease in gastric acidity.
The motivation to crib was compared to the motivation to eat. Eight horses (Equus caballus) were operantly conditioned to push a switch for the opportunity to crib. When a progressive ratio was imposed, they worked as hard for a cribbing opportunity as for the opportunity to
eat sweetened grain indicating a high demand. Another measure of motivation is the effort expended by the animal. The force exerted when a horse cribs was measured by attaching weights to a door and observing how heavy the weights had to be to prevent the horse from pulling a door toward itself
when it cribbed. Seven horses were tested. Each neck flex of a crib-biting action was forceful enough to lift 29.4 (± 5) kg. The motivation to crib and the force involved indicates that thwarting cribbing is a welfare issue.
The effect of short periods of strenuous exertion, in this case treadmill exercise, on the subsequent behavior of Standardbred horses was examined. Six horses were exercised on a high-speed treadmill 4 or 5 days per week, for 3–4 miles (approximately 1.8 m s−1 for 3 min, 5 m s−1 for 12 min, 9 m s−1 for 3 min, 3 m s−1 for 3 min, 1.8 m s−1 for 3 min). The behavior of the horses was observed in the horse's home stall immediately after exercise and 2–7 h after exercise. Focal animal sampling for a total of 150 h revealed that the horses spent significantly more time drinking and less time resting after exercise than they did on control (non-exercise or rest days). The greatest influence on behavior was seen immediately after exercise. The horses spent 13.2±2.7 s per 15 min drinking after exercise and 7.2±2.3 s per 15 min drinking on non-exercise days. They spent 7.3±1.5 min h−1 stand resting after exercise and 9.7±2.1 min h−1 on non-exercise days. These changes in behavior may be related to the physiological changes that accompany exercise. Eating, walking, elimination and self-grooming were not significantly influenced by exercise.In a second experiment the activities of two groups of six Standardbred mares were compared. One group was exercised on the treadmill and the other was not. The exercised horses spent more time drinking and lying, but urinated less than the non-exercised group.
Data were gathered on the behavioural and physiological characteristics of five cribbers, six weavers and six non-stereotypic (control) mature Thoroughbred geldings for a period of 16 weeks. The horses were hired from their owners and stabled individually throughout the trial. Cribbers and weavers had been known to stereotype for at least 12 months prior to commencement of the study. Behavioural data were collected using video surveillance. Cribbers stereotyped most frequently (P < 0.001) in the period 2-8 h following delivery of concentrated food, reinforcing the suggestion that diet is implicated in cribbing behaviour. Weavers stereotyped most frequently (P < 0.001) during periods of high environmental activity such as during routine pre-feeding activities and in the hour prior to daily turnout, presumably when anticipation and stimulation were at their highest levels. Cribbers and weavers took longer than control horses to fully consume their ration, suggesting possible differences in motivation to feed, distress levels, satiety mechanisms or abdominal discomfort. Physiological data were collected throughout the trial and there were no differences in oro-caecal transit time, digestibility, plasma cortisol concentration or heart rate among the three behavioural groups. (c) 2007 Elsevier B.V. All rights reserved.
Five cribbing horses and six control horses were used in a latin square design dietary study to investigate the effects of different diets on the frequency of cribbing behavior and plasma levels of beta-endorphin in the horse. Feeding grain or sweetened grain rations was found to cause a significant increase in the cribbing frequency whereas alfalfa pelleted hay was without significant effect on the frequency of the behavior. Baseline beta-endorphin levels in cribbing horses were half those of the non-cribbing controls and remained significantly lower during the feeding trials. These results are discussed as they apply to treatment of cribbing horses and in terms of the underlying mechanism of cribbing.
Environmental enrichment is a vague concept referring to improvements to captive animal environments. Some authors have applied the term to an environmental treatment itself, without any concrete evidence that the treatment represented an improvement for the animals. Others have used the term when the main beneficiaries may have been people rather than their captive animals. The criteria used to assess enrichment have also varied according to animal use (e.g. laboratory, farm or zoo animals). In this paper, environmental enrichment is defined as an improvement in the biological functioning of captive animals resulting from modifications to their environment. Evidence of improved biological functioning could include increased lifetime reproductive success, increased inclusive fitness or a correlate of these such as improved health. However, specifying an appropriate endpoint is problematic, especially for domestic animals. Potential methods of achieving enrichment that require further investigation include presenting food in ways that stimulate foraging behaviour and dividing enclosures into different functional areas. The quality of the external environment within the animals' sensory range also deserves greater attention. A common shortcoming of attempts at environmental enrichment is the provision of toys, music or other stimuli having little functional relevance to the animals. Failure to consider the effects of developmental factors and previous experience can also produce poor results. Environmental enrichment is constrained by financial costs and time demands on caretakers, and providing live prey to enrich the environment of predators raises ethical concerns. Future research on environmental enrichment would benefit from improved knowledge of the functions of behaviour performed in captivity and more rigorous experimental design.
Average daily core body temperature and behavioural patterns of pregnant mares were studied, in search of definitive signs of parturition within 24 h of the event. Nineteen pony mares were sampled twice daily for core body temperature. A significant temperature drop, averaging 0.1°C (0.2°F) was observed during the day prior to parturition. Between 18.00 h and 06.00 h, during the two weeks before parturition, Thoroughbred and Standardbred mares (n=52) spent an average 66.8 per cent of their time standing, 27.0 per cent eating, 4.9 per cent lying in sternal recumbency, 1.0 per cent lying in lateral recumbency, and 0.3 per cent walking. On the night before parturition, mares spent significantly less time lying in sternal recumbency than on previous nights and on the night of parturition all behaviour patterns except eating were significantly different from the nights of the two weeks before parturition. There was an increase in walking (5.3 per cent), lying in sternal recumbency (8 per cent) and lying in lateral recumbency (5.3 per cent) whereas standing (53.3 per cent) was decreased. In 58 observed pregnancies, 54 mares (97 per cent) foaled in a recumbent position and 50 mares (86 per cent) foaled between 18.00 h and 06.00 h.
Stress at work, as shown by a number of human studies, may lead to a variety of negative and durable effects, such as impaired psychological functioning (anxiety, depression...). Horses share with humans this characteristic of working on a daily basis and are submitted then to work stressors related to physical constraints and/or more "psychological" conflicts, such as potential controversial orders from the riders or the requirement to suppress emotions. On another hand, horses may perform abnormal repetitive behaviour ("stereotypies") in response to adverse life conditions. In the present study, we investigated whether the type of work the horses are used for may have an impact on their tendency to show stereotypic behaviour (and its type) outside work. Observations in their box of 76 horses all living in the same conditions, belonging to one breed and one sex, revealed that the prevalence and types of stereotypies performed strongly depended upon the type of work they were used for. The stereotypies observed involved mostly mouth movements and head tossing/nodding. Work constraints probably added to unfavourable living conditions, favouring the emergence of chronic abnormal behaviours. This is especially remarkable as the 23 hours spent in the box were influenced by the one hour work performed every day. To our knowledge, this is the first evidence of potential effects of work stressors on the emergence of abnormal behaviours in an animal species. It raises an important line of thought on the chronic impact of the work situation on the daily life of individuals.
Crib-biting in horses is a repetitive behavior pattern which may involve the activation of both narcotic receptors and dopamine receptors in the CNS. Crib-biting frequency, determined in 7 nontreated horses under controlled conditions, was usually linear for many hours and ranged from 0.3 to 14.9 bites/min. Intravenous or IM injections of narcotic antagonists decreased these rates to almost zero by about 20 minutes after the injection was given. The duration of the response to a single injection ranged from 20 minutes for naloxone to 4 hours or more for nalmefene and diprenorphine. Effective doses were 0.02 to 0.04 mg of naloxone/kg, 0.04 mg of naltrexone/kg, 0.08 mg of nalmefene/kg, and 0.02 to 0.03 mg of diprenorphine/kg. Crib-biting could be prevented completely for up to a week by continuous infusion of 5 to 10 mg of nalmefene/hr. Crib-biting resumed when the infusion was discontinued, and plasma nalmefene concentrations decreased to below 5 ng/ml. Doses of nalmefene as large as 0.4 mg/kg, IV, produced only minor side effects. These side effects included some passage of semifluid fecal material, intermittent penile relaxation, and mild sedation. Treated horses responded normally to external stimuli, retained their appetites, and performed appropriately when ridden. Sedation wore off during the course of prolonged infusions. Narcotic antagonists may provide a novel and effective treatment of stereotypic behavior disorders.
Stereotypic cribbing in horses is thought to involve excess dopaminergic activity within the striatum. Various models of stress-induced stereotypies including cribbing in horses postulate that stress stimulates the release of endorphins, triggering the release of striatal dopamine. Dopamine in turn activates basal ganglia motor programs, reinforcing behavior via a reward mechanism. Furthermore, the release of dopamine by endorphins has been shown to depend on activation of NMDA receptors. In the present study, horses identified as cribbers and volunteered by their owners were treated with the NMDA receptor antagonist dextromethorphan (DM). When DM was administered via jugular injection (1 mg/kg), eight of nine horses responded with reductions in cribbing rate (CR) compared to baseline, and cribbing was suppressed completely for a period of time in almost half of the horses tested.
A telephone survey was conducted of 100 racing stables, 100 riding schools and 100 competition establishments (8,427 horses in total) to determine what management practices were being applied to horses showing stereotypic behaviour, and to determine the underlying reasons for them by assessing the perceptions and opinions of the people working with the horses. The results indicated that horse owners are concerned about stereotypic behaviour, first, because it reduces the performance of the animal (31, 30 and 27 per cent of the owners of racing stables, riding schools and competition establishments respectively), secondly, because it has adverse clinical effects on the horse (52, 55 and 56 per cent), and thirdly, because it reduces the monetary value of the animal (45, 59 and 31 per cent). The belief that these behaviours are learnt or copied also affects the management of affected horses: they are not allowed on to the premises by 4, 32 and 17 per cent of owners of racing stables, riding schools and competition establishments, respectively; attempts are made to remove the causal factors of the stereotypy by 35, 43 and 36 per cent; the behaviours are physically prevented by 77, 67 and 79 per cent, and the affected horses are kept separate from other horses by 39, 30 and 48 per cent.
In North America, there are few representative data about the effects of management practices on equine welfare. In a randomized survey of 312 nonracing horses in Prince Edward Island (response rate 68.4%), owners completed a pretested questionnaire and a veterinarian examined each horse. Regression analyses identified factors affecting 2 welfare markers: body condition score (BCS) and stereotypic behavior. Horses' BCSs were high (mean 5.7, on a 9-point scale) and were associated with sex (males had lower BCSs than females; P < 0.001) and examination date (P = 0.052). Prevalences of crib biting, wind sucking, and weaving were 3.8%, 3.8%, and 4.8%, respectively. Age (OR = 1.07, P = 0.08) and hours worked weekly (OR = 1.12, P = 0.03) were risk factors for weaving. Straw bedding (OR = 0.3, P = 0.03), daily hours at pasture (OR = 0.94, P = 0.02), and horse type (drafts and miniatures had a lower risk than light horses; P = 0.12) reduced the risk of horses showing oral stereotypies. Some of these results contradict those of other studies perhaps because of populations concerned.
This 2nd edition is a complete re-write of the 1st edition in 1993. It reflects developments in knowledge since the 1st edition and includes many new chapters and contributors. Concern over the welfare of confined animals is continuing to increase and extends not only to farm and zoo animals, but also to laboratory and companion animals. This book focuses on environmentally induced stereotypes, rather than drug induced or neurologically based stereotypes and discusses why captive animals perform these stereotypes. It also examines what this behaviour can tell us about animal welfare, options for prevention and cure and assesses future research directions and implications for animal welfare.
Diurnal pattern of cribbing in three horses, whose cribbing became habitual and persistent, were observed in stalls for 24 hours using video recorders. The frequency of cribbing varied in a day, with three major cribbing periods in early morning, evening and midnight. There was a strong association between the frequency of cribbing and feeding. Before and after the roughage meal delivery, the level of cribbing frequency was low, and around the concentrated meal delivery, the level of cribbing frequency became high. These results suggest that cribbing may be caused not only by boredom, but also by frustration in ingestive behavior related to the physical quality of the meal which horses are fed.
The aim of the present study was to identify relations between stereotyped behaviours (cribbing, weaving and box-walking) and wood-chewing in thoroughbred flat-racing horses (TB) and standardbred trotters and the different management, feeding and training factors to which these horses are exposed. This was obtained by inquiries to all the professional trainers of TB and trottinghorses used for racing in Sweden. The usable response rates were 61% for trotters and 72% for TB representing 4597 trotters from 234 stables and 644 TB from 38 stables. A small field study was carried out to control the validity of the main study which gave results similar to those in the main study. There was a large difference between the two horse categories in the occurrence of behavioural disturbances. The TB had significantly more stereotypies than the trotters (P < 0·001) but there were no differences in the occurrence of wood-chewing. There were several differences in external factors between the horse categories, e.g. trotters had more opportunities for social contacts with other horses, they also had more free time outside the stable and they were trained a shorter time per week than the TB. The TB were given larger amounts of concentrate than the trotters. Wood-chewing within each horse category was explained by the amount of roughage (P < 0·05 in trotters and P < 0·001 in TB) together with other factors. Stereotypies in the TB were explained by: amount of concentrate (positive relation), number of horses per trainer (positive relation) and amount of roughage (negative relation).
During the past decade, stereotypic behavior in horses, specifically crib-biting behavior, has received considerable attention in the scientific literature. Epidemiological and experimental studies designed to investigate crib-biting behavior have provided valuable insight into the prevalence, underlying mechanisms, and owner perceptions of the behavior. The findings of these studies have demonstrated how the management of horses can influence their behavior and well being. Management conditions which impede foraging opportunities and social contact, provision of high concentrate diets, and abrupt weaning have been associated with an increased risk of crib-biting. The exact etiology of crib-biting remains to be elucidated, however, results of recent research suggest that dopaminergic pathways may be implicated in the performance of this oral stereotypy. There has also been additional evidence to support the hypothesis that gastrointestinal irritation is involved in crib-biting in horses. Many equine behavior and welfare scientists remain in agreement that management of crib-biting horses should focus on addressing the suspected influential factors prior to attempts at physical prevention of the behavior. The findings of several survey and experimental studies are reviewed, with emphasis on research conducted since the late 1990s, in an effort to provide the reader with a relatively comprehensive look into that which is known about crib-biting behavior in horses. Knowledge deficiencies and areas for future research are identified.
In recent studies of equine stereotypic behaviour, data on levels of cortisol and beta-endorphin (BE) have been limited and sometimes contradictory. The current research aimed to investigate, in a large number of horses, the relationships between these compounds and equine stereotypic behaviour. Plasma and salivary cortisol levels were measured in stereotypic (n=46) and normal horses (n=46) to determine whether a significant difference exists between these two groups. No significant differences were found between the mean plasma or salivary cortisol concentrations of stereotypic and normal horses, indicating that their arousal levels are similar. The correlation between plasma and salivary cortisol concentrations of individual horses (n=66) was also examined. A significant correlation between plasma and salivary cortisol levels was found only in horses with an oral stereotypy (r=0.65; P=0.01), which has implications for the use of salivary cortisol as a cardinal indicator of equine acute physiological stress responses. Additionally, plasma BE levels were compared between horses with an oral stereotypy (n=17) and normal horses (n=17). Mean plasma BE levels did not differ significantly between the two groups. Since endogenous opioids are thought to facilitate stereotypic behaviour, and a hereditary component to stereotypic behaviour has been observed, this may suggest that stereotypic horses have inherited opioid receptors with a greater sensitivity than those of normal horses.
The objective of this study was to evaluate whether sex, age and/or coat colour were associated with the occurrence of stereotypic behaviour in the horse and to assess whether the occurrence of one type of stereotypy in an individual was associated with the occurrence of another specific type of stereotypy. The incidence of stereotypic boxwalking, weaving (both locomotor stereotypies) and oral stereotypy in 4061 Thoroughbred horses passing through five bloodstock auctions were recorded from sale declarations and information on returns. An overall prevalence of 5.1% was recorded, and varied with sex (P
Operant conditioning and two choice preference tests were used to assess the motivation of horses to be released from straight and from box stalls. The motivations for food, a companion, and release into a paddock were compared when the horses had to work for each commodity at increasing fixed ratios of responses (panel presses) to reward in an equine operant conditioning stall. The motivation for food (mean±SEM=258±143) responses was much greater than that for either release (38±32) from a straight stall into a large paddock alone or into a small paddock with another horse (95±41) (P=0.04). When given a two choice preference test between exercise on a treadmill for 20min or returning to their box stalls, eight of nine horses chose to return to their stalls. In a two choice preference test six of eight horses in box stalls chose to be released into a paddock alone. Horses were given a series of two choice preference tests to determine how long they preferred to be in a paddock. After 15min in the paddock the horses were re-tested, but all chose the paddock when released into a paddock with three other horses. They were retested every 15min until they chose to return to their stalls. They chose to stay out for 35±6min when other horses were in the paddock but for only 17±2min when they would be alone. When deprived of stall release for 48h the horses chose to remain in the paddock with other horses for 54±6min, but showed no compensatory behavior when they were alone (duration chosen=16±4min). These findings indicate that horses are not strongly motivated to exercise alone and will choose not to endure forced exercise on a treadmill. The social context of voluntary exercise is important; horses are willing to stay out of their stalls longer if other horses are present and will show compensatory behavior only if other horses are present. These finding have implications for optimizing turnout time for stalled horses.
SummaryA retrospective study of 43 cases of temporohyoid osteoarthropathy was performed to evaluate the epidemiological features and a possible association with crib-biting. Data collected from records included case details, what diagnostics were utilised, whether medical or surgical treatment was administered, and outcome. Owners were contacted via telephone and asked whether the horse had displayed crib-biting behaviour. Forty-three horses were diagnosed with neurological disease associated with temporohyoid osteoarthropathy, 62.8% of which were Quarter Horse-types. Median age at presentation was 10 years and median duration of neurological signs prior to presentation was 3 days. Skull radiographs and guttural pouch endoscopy were used to definitively diagnose temporohyoid osteoarthropathy in 72% of the cases. Of 43 horses, 21 received medical treatment and 15 surgical treatment, with an overall survival rate of 55.8%. Crib-biting was observed in 31.3% of cases and there was a significant association between being afflicted with THO and likelihood of possessing the behaviour. Horses with neurological disease associated with THO were 8 times more likely to be crib-biters compared to the general population.
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The investigation involved 1035 Thoroughbred horses aged 3-8 years and raised in Italy. Eighty trainers were interviewed on the occurrence of anomalous behaviour. The incidence of cribbing, weaving and stall-walking in the horses was 2.4, 2.5 and 2.5%, respectively. The incidence of behavioural defects in families containing identified anomalous horses ("probands") was much higher than in the surveyed population: 30% for cribbing, 26% for weaving and 13% for stall-walking. This would suggest the involvement of a genetic component in the three vices, but due to the limited data available it was not possible to ascertain the inheritance patterns. Imitation of mares by foals was excluded as a main cause of the vices.
The stabled (UK) or stalled (USA) horse is commonly fed a restricted-forage diet in contrast to the varied ad libitum high-fibre diet it evolved to consume. A low-forage diet has been linked to the performance of stereotypical behaviour and health problems including gastric ulceration and impaction colic (in cases where horses are bedded on straw). Provision of a diet closer to that which the horse is adapted to and which enables more natural feeding behaviour warrants investigation.This trial aimed to establish whether the behavioural effects observed in short-term trials when stabled horses were provided with a multiple forage diet persist over longer periods. It also aimed to develop a practical methodology for maintaining stabled horses under forage-enriched conditions.Nine horses (aged 5–20 years, various breeds), acting as their own controls, participated in an 18-day, cross-over, Latin Square designed trial, in which they received comparable weights of two dietary treatments: a Single Forage (SF, hay) diet and a Multiple Forage (MF) diet (three long-chop and three short-chop commercially available forages). Following a 2-day acclimatisation, horses were maintained on the forage treatments for 7 days. Horses were observed on alternate days, morning and afternoon, during the 25 min following forage presentation. Horses then crossed over onto their second treatment and, following a further 2 days’ acclimatisation, the same protocol was followed for a further 7 days. Observations from video were made using The Observer 3.0® and SPPS (version 11).Horses on the MF treatment performed foraging behaviour significantly more frequently and for significantly longer periods than horses on the SF treatment. On the MF treatment horses sampled all forages during observations. However, there were significant differences in the frequency and duration of foraging on individual forages, indicating that horses demonstrated individual preferences for particular forages. Stereotypic weaving behaviour only occurred on the SF treatment.The results indicate that the potentially beneficial behavioural effects of short-term multiple forage provision do persist when horses are managed on a MF diet for a 7-day period. They suggest that a MF diet provides a means of enriching the stabled horse's environment, by offering variety and enabling patch foraging behaviour. The methodology proved practical for maintaining horses under forage-enriched conditions and could easily be adopted by horse owners to facilitate foraging behaviour.
The natural diet of free-ranging horses is grass, which is typically high in fiber and calorically dilute, however diets for high performance domestic horses are often low in fiber and calorically dense. The aim of the study was to determine the motivation of horses for hay when fed a low roughage diet. Their motivation could be used to determine if low roughage diets compromise the welfare of horses. Eight mares were fed two different diets in counterbalanced order: ad libitum orchard grass hay; a complete pelleted feed (pellets). Each trial lasted three weeks, with a one-week transition period between diets. To determine the motivation of horses for fiber they were taught to press a panel to obtain a food reward. The fixed ratio (FR) was increased using a progressive ratio ((1,2,4,7,11…) technique. When fed pellets, the horses worked for a median FR of 1 (Range=1-497) to attain pellets, and when fed hay, they worked for a median FR of 25.5 (4-497) to attain pellets. When fed hay, the horses worked for a median FR of 0 (0-0) to attain hay, and when fed pellets, they worked for a FR of 13 (2-79) to attain hay. These results indicate a greater motivation for hay, a high fiber diet, when fed a low fiber diet. The horses spent 10 (5-19.4)% of their time during a 24-hour period eating pellets compared to 61.5 (29-76) % of their time eating hay. Horses spent 58% of their time standing when fed the pellets and only 37% of their time standing when fed hay. Searching behavior (i.e. sifting through wood shaving bedding for food particles) took up 11.5 (1.4-32) % of the horse's day when fed pellets, but only 1.2 (0-3.5) % of the daily time budget when fed hay. Horses chew more times when eating a hay diet (43,476chews/day) than when eating a pellet diet (10,036chews/day). Fecal pH was lower in horses fed the pelleted diet.
Crib-biting/windsucking behaviour has important consequences for equine health and welfare. Lay perceptions of health and illness are of interest to medical sociologists, providing important information to medical practitioners, but have infrequently been applied in veterinary research.
To demonstrate how lay epidemiology can be applied within veterinary research by exploring the lay perceptions regarding the causes of crib-biting/windsucking behaviour in horses.
Informants were recruited from professional and amateur horse owners who had or had not owned/cared for a horse that exhibited crib-biting/windsucking behaviour. In-depth interviews were used to examine perceptions about the development of this behaviour within each group until a 'saturation' of themes emerged.
The main themes that emerged as causes of crib-biting/windsucking behaviour were 'boredom', 'stress' and 'habit/addiction'. In the group of owners/carers who did not have direct experience of this type of behaviour, 'copying' from other horses emerged as a strong theme and they stated that they would not wish to own a crib-biting/windsucking horse. In contrast, those who had direct experience of horses demonstrating this behaviour did not believe copying was a cause based on their own observations and would not be put off purchasing or caring for another horse displaying this behaviour.
Perceptions about what causes crib-biting/windsucking was influenced by whether or not informants had personal experience of horses demonstrating this behaviour. The three main themes that emerged have some justification based on current research and highlight the need for further investigation into the underlying pathophysiology of crib-biting/windsucking behaviour.
Qualitative approaches to health, disease and behaviour have an important role in the medical field and are applicable to veterinary research.
Crib-biting is an equine stereotype that may result in diseases such as colic. Certain breeds and management factors have been associated.
To determine: breed prevalence of crib-biting in US horses; the likelihood that one horse learns to crib-bite from another; and owner perceptions of causal factors.
An initial postal survey queried the number and breed of crib-biting horses and if a horse began after being exposed to a horse with this habit. In a follow-up survey, a volunteer subset of owners was asked the number of affected and nonaffected horses of each breed and the extent of conspecific contact. The likelihood of crib-biting given breed and extent of contact was quantified using odds ratio (OR) and significance of the association was assessed using the Chi-squared test.
Overall prevalence was 4.4%. Thoroughbreds were the breed most affected (133%). Approximately half of owners believed environmental factors predominantly cause the condition (54.4%) and crib-biting is learned by observation (48.8%). However, only 1.0% of horses became affected after being exposed to a crib-biter. The majority (86%) of horses was turned out in the same pasture with other horses and extent of contact with conspecifics was not statistically related to risk.
This is the first study to report breed prevalence for crib-biting in US horses. Thoroughbreds were the breed more likely to be affected. More owners believed either environmental conditions were a predominant cause or a combination of genetic and environmental factors contributes to the behaviour. Only a small number of horses reportedly began to crib-bite after being exposed to an affected individual, but approximately half of owners considered it to be a learned behaviour; most owners did not isolate affected horses.
Genetic predisposition, not just intensive management conditions and surroundings, may be a factor in the high crib-biting prevalence in some breeds, and warrants further investigation. Little evidence exists to suggest horses learn the behaviour from other horses, and isolation may cause unnecessary stress.
Intraoral infusions of sucrose, fat or polycose reduce ultrasonic vocalizations during isolation, and increase pain threshold in infant rats. These effects are naltrexone reversible. The present study determined whether these substances, when paired with an odor, caused a change in preference for that odor. In 6-day-old rats, pairing orange odor with intraoral infusions of sucrose or corn oil, but not polycose, water, mineral oil or 0.01% quinine hydrochloride, caused a substantial increase in preference for orange. Preference formation was blocked by systemic injection of naltrexone (0.25 mg/kg) prior to pairing orange with either sucrose or corn oil. Moreover, preference expression was prevented by naltrexone injection prior to testing. Thus certain substances thought to reduce stress in infant rats via endogenous opioid release can also cause preference for substances that predict their occurrence. Preference formation depends upon the availability of endogenous opioids. Preference expression reflects the conditioned stimulus causing opioid release.
There is confusion in the veterinary literature concerning the definition of oral based stereotypies in the horse. This study reports the use of fluoroscopy and endoscopy during cribbiting/wind-sucking in afflicted horses. This permitted observations of movements of the pharyngeal and oesophageal tissues and of the air column within during the stereotypic behaviour. The findings reported show that the sequence of events during crib-biting/wind-sucking is not related to deglutition and that air is not swallowed to the stomach. Transient dilation of the upper oesophagus was recorded and the characteristic noise of wind-sucking coincided with the in-rush of air through the cricopharynx. The oesophageal distension was relieved when the air returned to the pharynx although small quantities passed caudally. It is proposed that the role of contraction of the strap muscles of the neck is to create a pressure gradient in the soft tissues surrounding the oesophagus which provokes movement of air from the pharynx into the oesophagus. The findings suggest that the definitions currently used in the sale of horses are in need of revision.
A greater knowledge of the effect of management factors is required to investigate the ontogeny of abnormal behaviour in the stabled horse. A postal survey of racehorse (flat) trainers yielded information about 22 yard and management factors. The relationship of the factors to the prevalence of abnormal behaviour was analysed by logistic regression. Management factors related to the time spent in the stable showed the strongest associations with stereotypic behaviour. The risk of horses performing abnormal behaviour increased: 1) as the amount of forage fell below 6.8 kg/day, 2) when bedding types other than straw were used, 3) when the total number of horses on the yard was fewer than 75, 4) in association with box designs that minimised contact between neighbouring horses, 5) when hay, rather than other types of forage, was used.
Repeated high doses of morphine sulfate, administered in a 24-36 h period, stimulates the expression of oral stereotypy in rats. Sensitization to this effect of morphine is demonstrated by the reexpression of the stereotypy by the administration of 4.0 mg/kg of morphine one week following the original exposure. To investigate the role of N-methyl-D-aspartic acid (NMDA) and D1 dopamine (DA) receptors in the acute expression and sensitization of morphine-induced oral stereotypy, rats were administered four injections of morphine (10.0 mg/kg) one injection every 12 h and observed for the expression of stereotypic behaviors following pretreatment with selective antagonists. Pretreatment with the NMDA antagonist, MK-801 (0.7 mg/kg), before each of the four morphine injections antagonized both the initial expression of oral stereotypy and the development of sensitization. In contrast, the DA D1 receptor antagonist SCH23390 (40.0 micrograms/kg) administered during the four high-dose treatments with morphine antagonized the initial expression of oral stereotypy and not the development of sensitization. These findings implicate glutamate's action at the NMDA receptor in both the acute expression of morphine-induced oral stereotypy, and the development of sensitization of this morphine effect, whereas DA D1 receptors may only be involved in the acute expression of the stereotypy.
The aim of the present study was to obtain information on the possible mechanisms underlying cribbing behaviour in horses. To investigate the horse's responsiveness to an external stimulus, a device for telemetric measurement of thermal threshold, using the forelimb withdrawal reflex, was developed and validated. Measurements of thermal threshold took place in cribbing horses (n = 11) before and during cribbing periods. Heart rate was monitored continuously in the same horses. Blood samples were collected before and during cribbing periods as well and in age- and sex-matched control horses (n = 11). β-endorphin and Cortisol were determined in plasma using radioimmunoassay techniques, serotonin was analysed by high performance liquid chromatography.
Compared with basal values, thermal threshold was significantly (P = 0.003) lower during cribbing periods. The mean difference was 4.9°C. Heart rate decreased significantly (P = 0.026) and showed a mean reduction of 2.4 beats/min during cribbing. Given the fact that arousal usually is associated with an increase in nociceptive threshold and in heart rate, the decrease in both during cribbing provide evidence that cribbing may reduce stress.
Cribbers showed 3 times higher basal β-endorphin levels than controls (mean 49.5 vs. 16.2 pmol/l, P = 0.006) and there was a trend for lower basal serotonin levels (mean 201.5 vs. 414.3 nmol/l, P = 0.07). These data indicate differences in cribber's endogenous opioid and serotonergic systems.
A researcher-administered survey study was performed involving 769 horses from 32 Thoroughbred, Standardbred, and pleasure horse stables in southwestern Ontario. Data were gathered on individuals (breed, age, and sex) and at the stable level (housing, management). The effects of these factors on cribbing, stall-walking, weaving, stall-kicking, tongue playing, and pawing were assessed by unconditional analysis (Chi-square, t test) and conditionally using stepwise logistic regression. Individual level factors had significant effects on most compulsive behaviours. Some stable level factors, in most cases, those related to type and amount of exercise, had a significant effect on the prevalence of compulsive behaviours when tested unconditionally, but were not significant if entered into a logistic regression model after stable type. Stall-kicking was more common in horses which had physical contact with other horses, and this factor remained significant in the logistic regression analysis. Stable level factors should be regarded as modulating factors rather than as causes and in some cases, may reflect an attempt to treat the problem. Increased turn-out of affected horses likely reflects an ineffective attempt to treat problems, while reduced forced exercise (riding, lungeing) of affected horses is more likely to represent a cause.
Stereotypies are invariant and repetitive behaviour patterns that seemingly have no function, which tend to develop in captive animals faced with insoluble problems and may be indicative of reduced welfare. A 4 year prospective study of the factors influencing the development of stereotypic and redirected behaviours (abnormal behaviour) in a population of 225 young Thoroughbred and part-Thoroughbred horses was conducted between 1995 and 1999. Abnormal behaviour affected 34.7% of the population. Multivariable analysis showed that foals of low- or middle-ranking mares were less likely to develop abnormal behaviour than foals of dominant mares (rate ratio (RR) 0.23, P<0.01; RR 0.48, P<0.01, respectively). Weaning by confinement in a stable or barn was associated with an increased rate of development of abnormal behaviour, compared with paddock-weaning (RR 2.19, P<0.05), and housing in barns, rather than at grass after weaning, was associated with a further increase (RR 2.54, P<0.01). Specific stereotypic and redirected behaviours were then considered as separate outcomes. Crib-biting was initiated by 10.5% of horses at median age 20 weeks, weaving by 4.6% of horses at median age 60 weeks, box-walking by 2.3% of horses at median age 64 weeks and wood-chewing by 30.3% of horses at median age 30 weeks. Wood-chewing developed at a lower rate in horses born to subordinate or mid-ranking mares than in horses born to dominant mares (RR 0.29, P<0.01; RR 0.41, P<0.01, respectively), and at a higher rate in horses kept in barns or stables rather than at grass after weaning (RR 4.49, P<0.001; RR 1A6, P<0.001, respectively). Feeding concentrates after weaning was associated with a 4-fold increase in the rate of development of crib-biting (RR 4.12, P = 0.02). The results of this study support the idea that simple changes in feeding, housing and weaning practices could substantially lower the incidence of abnormal behaviour in young horses.
Nineteen young horses that had recently started to perform the stereotypy of crib-biting were compared with 16 non-stereotypic horses for 14 weeks. After initial observations of their behaviour and an endoscopic examination of the condition of their stomachs, the horses were randomly allocated to a control or an antacid diet At the start of the trial, the stomachs of the crib-biting foals were significantly more ulcerated and inflamed than the stomachs of the normal foals. In addition, the faecal pH of the crib-biting foals (6.05) was significantly lower than that of the normal foals (6.58). The antacid diet resulted in a significant improvement in the condition of the horses' stomachs. The crib-biting behaviour declined in most of the foals, regardless of their diet, but tended to decline to a greater extent in the foals on the antacid diet.
Stress-induced changes in mesoaccumbens dopamine neurophysiology have been associated with the development of stereotypic behaviour in in-bred strains of laboratory rodents. This experiment evaluated whether similar changes are associated with environmentally-induced stereotypic behaviour in a higher-vertebrate species, the horse. D1- and D2-like dopamine receptor densities (B(max)) and dissociation constants (K(d)) were measured in control (n=9) and stereotypy (n=9) horses in the nucleus accumbens, caudate nucleus, putamen, substantia nigra and ventral tegmentum brain regions. Results revealed that stereotypy horses had significantly higher (P<0.05) dopamine D1 and D2 receptor densities (B(max)) in the nucleus accumbens compared to non-stereotypy controls. D1 receptor densities (B(max)) and D2 receptor affinity (K(d)) were also significantly lower in the caudate nucleus brain region of stereotypy horses (P<0.05). No other significant results were observed. These results demonstrate that stereotypy horses have increased activity within the mesoaccumbens dopamine pathway and, thus, that the development of environmentally-induced stereotypy may be associated with changes in motivational systems within the animal.
To determine whether there was an association between a history of cribbing and epiploic foramen entrapment (EFE) of the small intestine in horses.
Retrospective study.
68 horses examined at the University of Illinois or the University of Liverpool veterinary teaching hospitals.
For horses examined at the University of Illinois that underwent surgery because of strangulating small intestine lesions, information about cribbing was obtained through telephone calls with owners. For horses examined at the University of Liverpool that underwent surgery for colic for any reason, information about cribbing was obtained through a preoperative questionnaire.
13 of 19 (68%) horses with EFE examined at the University of Illinois had a history of cribbing, compared with only 2 of 34 (6%) horses with other strangulating small intestine lesions (odds ratio, 34.7; 95% confidence interval, 6.2 to 194.6). Similarly, 24 of 49 (49%) horses with EFE examined at the University of Liverpool had a history of cribbing, compared with 72 of 687 (10.5%) horses with colic caused by other lesions (odds ratio, 8.2; 95% confidence interval, 4.5 to 15.1).
Results suggest that there may be an association between cribbing and EFE in horses, with horses with a history of cribbing more likely to have EFE than horses without such a history.
Guide for the Care and Use of Agricultural Animals in Agricultural Research and Teaching Agricultural Animal Care Guide. Division of Agriculture, National Association of State Universities and Land-Grant Colleges Motivation for hay: effects of a pel-leted diet on behavior and physiology of horses
- D C Usa
- J B Elia
- H N Erb
- K Houpt
Consortium for Developing a Guide for the Care and Use of Agricultural Animals in Agricultural Research and Teaching, 1988. Guide for the Care and Use of Agricultural Animals in Agricultural Research and Teaching. Agricultural Animal Care Guide. Division of Agriculture, National Association of State Universities and Land-Grant Colleges, Washington, D.C., USA. Elia, J.B., Erb, H.N., Houpt, K., 2010. Motivation for hay: effects of a pel-leted diet on behavior and physiology of horses. Physiol. Behav. 101, 623–627.
Management factors associated with stereotypic and redirected behaviors in the Thoroughbred horse
- McGreevy