Efficacy and effects of various anti-crib devices on behaviour and physiology of crib-biting horses.

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 with 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 probably 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.

Comparative ingestive mastication in domestic horses and cattle: a pilot investigation.

It is often assumed that horses chew food more intensively during ingestion than cattle, which - as ruminants - complete part of the mastication during rumination. This has been proposed as a reason for more robust mandibles, larger masseter insertion areas and larger masseter muscles in horses as compared to cattle and other grazing ruminants. In this study, we evaluate results of comparative feeding trials with three horses (338-629 kg) and three cows (404-786 kg), on four different roughages. Ingestion time (s/g dry matter) and chewing intensity (chews/g dry matter) differed among animals within a species, indicating an influence of body mass, and differed significantly between different forages. However, although numerical differences clearly suggest that horses have longer ingestion times and higher chewing intensities on high-fibre roughage than do cattle, this could not be proven in this dataset, most likely because of the small number of individuals sampled. Further studies are required to corroborate the suspected ingestive behaviour difference between equids and ruminants.

Crib-biting in US horses: breed predispositions and owner perceptions of aetiology.

REASONS FOR PERFORMING STUDY: Crib-biting is an equine stereotype 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 (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. 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.

Efficacy of amitriptyline as a pharmacological adjunct to behavioral modification in the management of aggressive behaviors in dogs.

The efficacy of amitriptyline as a pharmacological adjunct to behavioral modification in the clinical management of aggressive behaviors in dogs was evaluated in two phases. Twelve dogs presenting for aggressive behaviors were treated sequentially with amitriptyline (2 mg/kg body weight, per os [PO] bid) and a placebo for 4 weeks in a prospective, randomized, double-blind, placebo-controlled trial. Standardized protocols for behavior modification were implemented throughout the trial. Owners maintained behavioral records and reported on the number of aggressive incidents as well as the dog's overall improvement at the end of each 4-week period. In the second phase, 27 cases of dogs presenting for aggressive behaviors and treated with amitriptyline were reviewed, and clients were contacted to record each dog's response to treatment. Reports were compared to those for dogs receiving behavior modification alone (i.e., placebo phase of prospective study). No significant difference was observed in the patients' responses to adjunctive amitriptyline versus behavior modification alone.

Differences in background and outcome of three behavior problems of dogs.

In order to characterize the three major behavior problems, aggression toward owners, aggression toward strangers and separation anxiety, backgrounds of dogs and general outcomes of the behavioral treatments were analyzed retrospectively. There were 169 cases of aggression toward owners, 84 cases of aggression toward strangers and 78 cases of separation anxiety which did not overlap each other during the 5 years from 1993 to 1997 at Cornell University Animal Behavior Clinic. Based on the case records, including discharge instructions, follow-up information, and pre-presentation questionnaires, several variables were compared among these three groups. The sexual status of these groups was not statistically different, although dogs with aggression toward owners had the highest proportion of males and there were more males in all behavior groups than in the hospital population. Also, breed types were different among three groups with a significantly higher proportion of mixed breed dogs among dogs with separation anxiety and aggression to strangers as compared to dogs with aggression to owners and to the hospital population. A higher percentage of dogs in the separation anxiety group tended to live in apartments and to be disciplined only verbally by the owner than in the other two groups. Age differences were apparent among the three groups in relation to when the dogs were obtained, and the separation anxiety group was different from at least one of the other groups in the age when first obtained, the age the owners first noticed the problem, and the age of behavioral examination. Regarding the general outcome of the behavioral treatment, there were no significant differences among the behavioral groups with regards to the proportion of dogs reported improved. These results provide new characterizations of these three major behavior problems.

Attitudes of owners regarding tendonectomy and onychectomy in cats.

OBJECTIVE: To compare the incidence of behavior problems following tendonectomy or onychectomy in cats, as well as attitudes of owners following these procedures. DESIGN: Nonrandomized clinical trial. ANIMALS: 18 cats that underwent tendonectomy and 39 cats that underwent onychectomy. PROCEDURE: Owners of cats that underwent tendonectomy or onychectomy between February 1993 and May 1998 were contacted by telephone and asked several questions regarding reasons for surgery as well as complications and behavioral changes in cats following surgery. RESULTS: The most common reason for considering tendonectomy or onychectomy was to avoid damage caused by the cat scratching household materials. Avoidance of injury to humans or animals was chosen more often by owners whose cats underwent onychectomy than those that underwent tendonectomy. Tendonectomy was more likely to have been recommended by veterinarians than onychectomy. Significantly more cats that underwent tendonectomy (67%) than onychectomy (44%) returned to normal activity within 3 days after surgery. Significant differences were not detected regarding behavior problems after surgery. CONCLUSIONS AND CLINICAL RELEVANCE: Although tendonectomy and onychectomy involved some medical complications and behavior changes following surgery, owners had positive attitudes regarding both surgeries after the immediate postoperative period. Tendonectomy may be a humane alternative to onychectomy, although owners need to be advised that nail trimming is still necessary in cats after surgery.

Effect of water restriction on equine behaviour and physiology.

Six pregnant mares were used to determine what level of water restriction causes physiological and/or behavioural changes indicative of stress. Nonlegume hay was fed ad libitum. During the first week of restriction, 5 l water/100 kg bwt was available, during the second week 4 l/100 kg bwt and, during the third week, 3 l/100 kg bwt. Ad libitum water intake was 6.9 l/100 kg bwt; at 3 l/100 kg bwt water intake was 42% of this. Daily hay intake fell significantly with increasing water restriction from 12.9 +/- 0.75 kg to 8.3 +/- 0.54 kg; bodyweight fell significantly for a total loss of 48.5 +/- 8.3 kg in 3 weeks. Daily blood samples were analysed; osmolality rose significantly with increasing water restriction from 282 +/- 0.7 mosmols/kg to 293.3 +/- 0.8 mosmols/kg bwt, but plasma protein and PCV did not change significantly. Cortisol concentrations fell from 8.1 ng/ml to 6.4 ng/ml over the 3 week period. Aldosterone fell from 211.3 +/- 74.2 pg/ml to 92.5 +/- 27.5 pg/ml at the end of the first week. The behaviour of 4 of the 6 mares was recorded 24 h/day for the duration of the study. The only significant difference was in time spent eating, which decreased with increasing water restriction from 46 +/- 3% to 30 +/- 3%. It is concluded that water restriction to 4 l/100 kg bwt dehydrates pregnant mares and may diminish their welfare, but is not life- or pregnancy-threatening.

Evaluation of treatments for separation anxiety in dogs.

OBJECTIVE: To evaluate treatment outcome in dogs with separation anxiety and owner compliance with and perception of effectiveness of discharge instructions. DESIGN: Cohort study. ANIMALS: 52 dogs with separation anxiety. PROCEDURE: Sex, age at which the owner obtained the dog, age at which separation anxiety was first noticed, age at behavioral examination, and discharge instructions were obtained from medical records of each dog. Between 6 and 64 months after the behavioral examination, owners were contacted by telephone and questioned about the outcome of treatment, their compliance with discharge instructions, and their perception of the effectiveness of each instruction. RESULTS: Thirty-two (62%) dogs had improved, whereas 20 were the same, were worse, or had been euthanatized or given away. Mixed-breed dogs were significantly less likely to improve than purebred dogs. Compliance varied according to discharge instruction. Significantly fewer dogs with owners that were given > 5 instructions improved or were cured, compared with those with owners given fewer instructions. Twenty-seven dogs were also treated with amitriptyline or other medication; 15 (56%) improved. CONCLUSIONS AND CLINICAL RELEVANCE: Owners complied with instructions that involved little time such as omitting punishment and providing a chew toy at the time of departure. Owners were also willing to increase the dog's exercise but were not willing to uncouple the cues of departure from real departures or desensitize the dog to impending departure. Administration of psychoactive medication may be necessary to augment behavior modification techniques designed to reduce separation anxiety in dogs.

A retrospective study of canine house soiling: diagnosis and treatment.

A retrospective study was conducted to determine the relative frequency and type of elimination problem seen in dogs at a university referral practice and to evaluate the efficacy of the suggested treatments. Cases presented to the Animal Behavior Clinic at Cornell University between 1987 and 1996 were reviewed. Of 1,173 cases, 105 (9%) were house-soiling cases. Of these cases, the authors obtained outcome information from 70. Within the diagnosis of house soiling, incomplete housebreaking (n=59; 84%) were the most frequent referral cases, of which 48 cases (81%; 95% confidence interval, 69% to 90%) improved. Separation anxiety was considered the second most common underlying cause (n=27; 39%), of which 85% (n=23; 95% confidence interval, 66% to 96%) improved. Behavior modification was the most often suggested treatment (n=58), with 48 (83%) cases improving. Behavior modification consisted of accompanying the dog to the preferred elimination area, rewarding the dog for eliminating there, and punishing the dog only when caught in the act of house soiling. These results suggest that correct house training, behavior modification involving positive reinforcement, and appropriate punishment are essential to diminish house-soiling problems in dogs.

Effect of castration on rabbits housed in littermate pairs.

Conventional solitary caging for research rabbits precludes many postural and social behaviors. Several studies that have investigated enrichment strategies for rabbit does have found intact males usually too aggressive for paired or group housing. This study investigated the possibilities that male siblings will remain compatible if never separated from birth and that castration will improve compatibility among young sibling male rabbits. As a side benefit of pair housing for all rabbits, the larger cages (modified dog cages) allowed rest and other postures not possible in conventional single cages. In addition, there was no evidence of the stereotypies observed among individually housed rabbits. Castrated, post-weanling, male, Flemish Giant x Giant Chinchilla rabbit littermates demonstrated a significantly higher level of living together compatibly than did the intact controls. All rabbits chose to rest in close proximity or contact, although this preference was stronger in castrated males. During puberty, intact males displayed more serious aggression. We conclude that young adult littermate rabbits can live compatibly as pairs and that castration improves compatibility among males. Paired rabbits exhibit many postures and behaviors that are not possible in the small, solitary cages currently listed as minimum recommendations.

Prevalence and characteristics of foal rejection in Arabian mares.

Separate surveys of Thoroughbred, Paint, and Arabian mare owners revealed a higher than expected rate of foal rejection in Arabian mares. A behavioural history form was submitted by owners of foal rejecting and nonrejecting Arabian mares, and maternal behaviour and management practices compared. Four generation pedigrees of rejecting and nonrejecting Arabian mares were also examined. Foal rejecting mares were more likely to avoid, threaten, squeal at, chase, bite, and kick their foals post partum than nonrejecting mares. Nonrejecting mares were more likely to lick, nicker and defend their foals post partum than rejecting mares. No statistically significant relationship was found between foal rejection and the type of breeding method (natural vs. artificial insemination), the presence of people at birth, the presence of nearby horses at birth, or assistance of the first nursing bout. The presence at least once of 1 of 2 related sires was statistically higher in the pedigrees of rejecting vs. nonrejecting mares. Inherited and learned or environmental factors are likely to affect the expression of foal rejection behaviour.

Sexual behavior problems in dogs and cats.

Sexual behavior problems do occur as a primary diagnosis, but excessive sexual behavior is a common secondary problem. Mounting occurs in almost half of dogs with behavior problems and 20% of cats with behavior problems.

Comparison of two antibarking collars for treatment of nuisance barking.

Two commercially available antibarking collars (i.e., a citronella spray collar and an electronic shock collar) were evaluated for efficacy and user satisfaction as reported by owners after a two-week trial period for each collar. While both collars were effective in decreasing barking (88.9% for the citronella spray collar and 44.4% for the electronic shock collar), most owners expressed a preference for the citronella spray collar. Owners perceived it as being more humane and indicated that they willingly would use it on a long-term basis to decrease their dogs' nuisance barking. While the citronella spray collar has some drawbacks, it is another tool for managing excessive barking.

Comparison of cerebrospinal fluid monoamine metabolite levels in dominant-aggressive and non-aggressive dogs.

Aggression has been shown to be related to reduced serotonergic activity in humans and non-human primates, and in rodents. We now studied the relationship between cerebrospinal fluid (CSF) monoamine metabolites and canine aggression in 21 dominant-aggressive dogs (Canis familiaris) and 19 controls. The diagnosis of dominance-related aggression was based upon a history of biting family members in contexts associated with dominance challenges. Post-mortem CSF 5-HIAA, MHPG and HVA were measured by high-performance liquid chromatography using electrochemical detection. Concentrations of CSF 5-HIAA (P = 0.01) and HVA (P < 0.001) were lower in the aggressive group (median values: 5-HIAA 202.0 pmol/ml; HVA 318.0 pmol/ml) than in controls (5-HIAA 298.0 pmol/ml; HVA 552.0 pmol/ml). No differences were noted in CSF MHPG levels. Differences in 5-HIAA were maintained after controlling for breed and age of dogs, but HVA differences may have been breed-dependent. Lower levels of 5-HIAA (P = 0.02) and HVA (P = 0.04) were found in the subgroup of aggressive dogs with a history of biting without warning (5-HIAA 196.0 pmol/ml; HVA 302.0 pmol/ml) compared to dogs that warned (5-HIAA 244.0 pmol/ml; HVA 400.0 pmol/ml). This study suggests that reduced serotonergic function is associated with aggressive behavior and impaired impulse control in dogs, a finding that is consistent with observations in primates, and suggests that serotonin modulates aggressive behavior throughout mammals.

Effect of dietary protein content on behavior in dogs.

OBJECTIVE: To determine the effect that feeding diets containing a low (17%), medium (25%), or high (32%) protein content would have on behavior in dogs. DESIGN: Prospective, controlled study. ANIMALS: 12 dogs with dominance aggression, 12 dogs with hyperactivity, 12 dogs with territorial aggression, and 14 control dogs without behavioral problems. PROCEDURE: Dogs were fed each of the diets for a 2-week period, and owners were instructed to score their dogs' behavior on a daily basis. RESULTS: Behavior of the dogs with dominance aggression, dogs with hyperactivity, and control dogs was unchanged by the dietary manipulations. Territorial aggression was significantly reduced when dogs were fed the low- or medium-protein diet, compared with territorial aggression when fed the high-protein diet. Post hoc analysis indicated that this effect was attributable to a marked reduction in aggression in a subset of the group (n = 7) in which territorial aggression was a result of fear. CLINICAL IMPLICATIONS: Results of this study suggest that a reduction in dietary protein content is not generally useful in the treatment of behavior problems in dogs, but may be appropriate in dogs with territorial aggression that is a result of fear.