|Home||<< 1 >>|
Albright, J. D., Mohammed, H. O., Heleski, C. R., Wickens, C. L., & Houpt, K. A. (2009). Crib-biting in US horses: Breed predispositions and owner perceptions of aetiology. Equine Veterinary Journal, 41(5), 455–458.
Abstract: Reasons for performing study: Crib-biting is an equine stereotypy that may result in diseases such as colic. Certain breeds and management factors have been associated.
Objectives: 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.
Methods: 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.
Results: Overall prevalence was 4.4%. Thoroughbreds were the breed most affected (13.3%). 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.
Conclusion: 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.
Potential relevance: 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.
Heleski, C. R., McGreevy, P. D., Kaiser, L. J., Lavagnino, M., Tans, E., Bello, N., et al. (2009). Effects on behaviour and rein tension on horses ridden with or without martingales and rein inserts. The Veterinary Journal, 181(1), 56–62.
Abstract: Unsteady hand position can cause discomfort to the horse, potentially leading to conflict behaviours (CB) such as head tossing or tail lashing. Some instructors feel that martingales or elastic rein inserts can reduce discomfort caused by inexperienced and unsteady hands. Others consider these devices to be inappropriate [`]crutches'. Four horses and nine riders were tested under three conditions in random order: plain reins, adjustable training martingales (TM), and elasticised rein inserts (RI). Rein-tension data (7Â s) and behavioural data (30Â s) were collected in each direction. Rein-tension data were collected via strain-gauge transducers. Behavioural data were assessed using an ethogram of defined behaviours. No differences in the number of CB were observed. Mean rein tension for TM was higher than that of RI or controls. Relative to the withers, the head was lower for horses ridden with martingales. Carefully fitted martingales may have a place in riding schools that teach novices.
Heleski, C. R., Shelle, A. C., Nielsen, B. D., & Zanella, A. J. (2002). Influence of housing on weanling horse behavior and subsequent welfare. Appl. Anim. Behav. Sci., 78(2-4), 291–302.
Abstract: Weaning foals marks a stressful event in horses' lives. Limited research exists regarding different housing methods post-weaning and the long-term implications on horse behavior and welfare. The purpose of this study was to monitor behavior and physiological stress markers in horses weaned individually in solid partition box stalls versus horses weaned in small groups and housed in paddocks. Both treatment groups underwent maternal deprivation stress, but the stalled weanlings had the additive effects of social isolation which prevented them from performing social behaviors. Quarter Horse weanlings from the Michigan State University, Merillat Equine Center, average age 4.5 months, were weaned in 13.4 m2 box stalls (n=6) or in groups of three in a 992 m2 paddock, which had very limited grazing forage and an open shelter available (n=6). Subjects were fed concentrate and hay to National Research Council recommendations. A time budget for 31 observed behaviors was developed. Behavioral observations were made 2 days per week, approximately 6 h per day, for the duration of the 56 days study. Instantaneous samples were recorded every 5 min on each observation day, with equal division between the two treatment groups (n=35 scans per horse per observation day). Focal data were recorded continuously between scans to provide a more detailed ethogram. On each observation day, fecal samples were collected to measure 11,17-dioxoandrostanes, an indicator of glucocorticoid metabolite concentration. Regarding the fecal 11,17-dioxoandrostanes, there was no discernible treatment difference either immediately post-weaning or at the conclusion of the 56 days study. Interestingly, all 12 weanlings showed a 4 week post-weaning increase in 11,17-dioxoandrostanes. The reason for this peak was unclear. Behavioral observations demonstrated a significantly different time budget in paddock-housed weanlings than in stall-housed weanlings (P<0.0001). Paddock-housed weanlings displayed a time budget more like a feral horse time budget, showing more time spent moving and less time spent lying. Paddock-housed weanlings, who had the option of selectively engaging in a broader range of behaviors, showed strong motivation to graze and be near conspecifics. Stalled weanlings spent significantly more time engaged in aberrant behaviors: licking or chewing the stall/shed wall, kicking at the stall/shed wall, pawing, and bucking/rearing bouts (P<0.03). Based on the variety of behaviors shown, the ability to engage in strongly preferred behaviors, and freedom from aberrant behavior, we conclude that the paddock-reared, group-housed weanlings had better welfare. However, there was insufficient evidence to conclude that the stalled weanlings had poor welfare.
Kaiser, L., Heleski, C. R., Siegford, J., & Smith, K. A. (2006). Stress-related behaviors among horses used in a therapeutic riding program. J Am Vet Med Assoc, 228(1), 39–45.
Abstract: OBJECTIVE: To determine whether therapeutic riding resulted in higher levels of stress or frustration for horses than did recreational riding and whether therapeutic riding with at-risk individuals was more stressful for the horses than was therapeutic riding with individuals with physical or emotional handicaps. DESIGN: Observational study. ANIMALS: 14 horses in a therapeutic riding program. PROCEDURE: An ethogram of equine behaviors was created, and horses were observed while ridden by 5 groups of riders (recreational riders, physically handicapped riders, psychologically handicapped riders, at risk children, and special education children). Number of stress-related behaviors (ears pinned back, head raised, head turned, head tossed, head shaken, head down, and defecation) was compared among groups. RESULTS: No significant differences in mean number of stress-related behaviors were found when horses were ridden by recreational riders, physically handicapped riders, psychologically handicapped riders, or special education children. However, mean number of stress-related behaviors was significantly higher when horses were ridden by the at-risk children. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that for horses in a therapeutic riding program, being ridden by physically or psychologically handicapped individuals is no more stressful for the horses than is being ridden in the same setting by recreational riders. However, at-risk children caused more stress to the horses, suggesting that the time horses are ridden by at-risk children should be limited both daily and weekly.
Kaiser, L., Smith, K. A., Heleski, C. R., & Spence, L. J. (2006). Effects of a therapeutic riding program on at-risk and special education children. J Am Vet Med Assoc, 228(1), 46–52.
Abstract: OBJECTIVE: To determine the effects of a therapeutic riding program on psychosocial measurements among children considered at risk for poor performance or failure in school or life and among children in special education programs. DESIGN: Observational study. POPULATION: 17 at-risk children (6 boys and 11 girls) and 14 special education children (7 boys and 7 girls). PROCEDURE: For the at-risk children, anger, anxiety, perceived self-competence, and physical coordination were assessed. For the special education children, anger and cheerfulness were measured, and the children's and their mothers' perceptions of the children's behavior were assessed. Measurements were made before and after an 8-session therapeutic riding program. RESULTS: For boys enrolled in the special education program, anger was significantly decreased after completion of the riding program. The boys' mothers also perceived significant improvements in their children's behavior after completion of the program. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that an 8-session therapeutic riding program can significantly decrease anger in adolescent boys in a special education program and positively affect their mothers' perception of the boys' behavior.
Moons, C., Heleski, C. R., Leece, C. M., & Zanella, A. J. (2002). Conflicting Results in the Association Between Plasma and Salivary Cortisol Levels in Foals.
Glucocorticoids are present in many biological fluids as a free fraction or bound to Corticoid
Binding Globulins (CBG) (Matteri et al, 2000). There are conflicting claims regarding the validity of
saliva as a biological fluid to measure cortisol in horses (Lebelt et al, 1996; McGreevy and Pell, 1998;
van der Kolk et al, 2001). Measuring changes in salivary cortisol levels in normal horses and horses
with Cushing`s disease van der Kolk and collaborators (2001) demonstrated the validity of saliva to
assess adrenal function. Puzzling results were reported by McGreevy and Pell (1998) who suggested
that plasma and salivary cortisol concentrations in horses showing oral stereotypies were correlated
but this association was non-existent in control animals. Investigating the responses of foals to
branding and foot-trimming Zanella et al (unpublished results) were unable to identify a relationship
between plasma and salivary cortisol levels in foals. In several species, levels of cortisol in plasma and
saliva are tightly correlated (Fenske, 1996). Cortisol found in blood consists of a fraction bound to
corticoid binding globulin (CBG) and a free, unbound fraction. Free cortisol represents the
biologically active fraction of this steroid hormone. Salivary cortisol reflects the unbound fraction
found in plasma or serum and it passes readily through the parotid membrane (Riad-Fahmy, 1983;
Horning Walker et al,1977). Unbound steroids transfer rapidly between plasma and saliva
(Walker,1989; Scott et al 1990). Saliva flow-rate does not appear to influence saliva cortisol levels in
different species (Hubert and de Jong-Meyer, 1989; Walker 1989, Scott et a, 1990). In horses, Lebelt
et al (1996) reported that salivary and plasma total cortisol in stallions were correlated. We
hypothesized that changes in salivary cortisol in foals would show a pattern that is correlated to that of
plasma free and plasma total cortisol concentrations in foals. In addition, we anticipated that the lack
of good sampling techniques provides an explanation for the failure in determining the association
between salivary and plasma cortisol in foals.