Materials and Methods

Animals—To be included in the study, dogs were required to be a minimum of 8 weeks of age and older at the time of recruitment (no more than 15 weeks of age at the start of the class) and were required to have been obtained as a companion or pet. Participating puppies were also required to be up-to-date on vaccinations (against canine parvovirus, canine adenovirus-2, distemper virus, parainfluenza virus, and Bordetella bronchiseptica) at least 1 week prior to the first class, have had a veterinary examination in which no health problems were identified, have negative results for parasitologic examination of fecal specimens, and be treated with a veterinarian-approved deworming product for roundworms and hookworms and topical external parasite control product. Dogs were excluded when they had previously participated in formal training or puppy classes. Only data from puppies that attended the first and last classes and at least 75% of all classes were included. To minimize attrition, the importance of completing the study was explained to participating owners. There was no active recruitment of dogs for the trial. Every owner that contacted staff at the puppy school to enroll their dogs for classes was screened to ensure that all inclusion criteria were met. All puppies that met the criteria were designated as small- or large-breed dogs, and owners were given a choice of 1 of 2 nights to attend classes, until each class met its quota.

Study design—The study was designed as a randomized, double-blind, controlled clinical trial in which the effects of DAP collars were compared with those of placebo collars for 8 weeks during 8 sessions of puppy classes. Each class was scheduled to last for 1 hour, including 15 minutes of controlled and supervised playtime. Throughout the study, the investigator (SD), owners, and trainers were unaware of the treatment group to which puppies had been assigned. All collars had the same color, shape, texture, weight, and size. Because the duration of effect of the DAP collar is reportedly 4 weeks,¹⁶ collars were replaced on each puppy with the same type of collar after 4 weeks. Owners were instructed to keep the collar on their puppy at all times during the 8 weeks, prevent the puppy from removing the collar, and avoid getting the collar wet. Owners were instructed to remove collars when bathing puppies and replace them when puppies were fully dry.

Puppies were allocated to 1 of 4 groups: large or small breed with DAP collars (DAP groups) and large or small breed with placebo collars (placebo groups). Dogs with an expected adult body weight < 25 kg (55 lb) were classified as small-breed dogs, and those expected to have an adult body weight ≥ 25 kg were classified as large-breed dogs. Puppies were allocated to separate classes on the basis of size to promote a better environment for training and play, and owners were not directed as to which class to choose on the basis of any other factor.

Training—Each trainer trained 1 group of DAP puppies and 1 group of placebo puppies. Both trainers were members of the Canadian Association of Professional Pet Dog Trainers, had a minimum of 8 years' experience in teaching puppy classes, used reinforcement-based techniques, and actively participated in continuing education seminars. To avoid any residual effects of DAP in the environment, classes were held on 2 nights and all puppies had the same type of collar each night.

Data collection—During each class, the investigator and trainers recorded the interactions between puppies and other puppies and between puppies and their owners. Any abnormal, unusual, or undesirable behavior of the puppies (ie, aggression, submissive urination, or display of anxiety or fear) and all behavior during playtime were also recorded. The investigator recorded owners' responses to the performance of their puppy, including positive reinforcement after successful completion of various commands and signs of frustration (eg, upset or disappointed tone of voice, limited or no reinforcement, or lack of desire to volunteer with their dog) when the puppy did not perform well.

Owners were asked to complete a questionnaire at each class. A baseline questionnaire administered prior to the first class (week 0) asked owners to evaluate their puppy with respect to amount of learning to date, degrees of excitability and fear, and behavior problems at the time of questionnaire completion. For weeks 1 through 6, a second questionnaire was administered at the end of each class. The second questionnaire asked owners to evaluate the degrees of excitability and fear and performance of their puppy at the specific class and to compare those statuses to the statuses at previous classes. Specific questions about the performance of puppies included response in the class as well as at home (where there might be fewer distractions), time it took for puppies to respond to a cue, quality (ie, accuracy and duration) of responses to commands, and number of times owners had to repeat commands. At week 7 (the eighth class), owners received the same questionnaire as that used in weeks 1 through 6; however, the questionnaire also included an additional section (ie, final questionnaire) in which owners were asked to compare the status of their puppy with respect to learning ability (in class and at home), degrees of fear and excitability, and changes in behavior problems, compared with respective statuses before the classes began. Owners were also asked about their impressions of usefulness of the collar and their overall satisfaction with their puppy, compared with their satisfaction prior to the beginning of classes.

Each question was explained to the owners by the investigator at week 0. Learning was defined as the ability to perform new commands and repeat them consistently. Fear was defined as any display of avoidance or retreat, submissive urination, or physical posture of fear (which may or may not have included aggression) in response to new stimuli, environments, dogs, or people. Excitability was defined as the inability of the puppy to stay focused and perform while other stimuli were present. Owners were also provided with standardized instructions for observing their dogs, which included drawings, photos, and verbal descriptions of fearful and anxious dogs to help them accurately classify the behavior of their puppy.

A 5-point scale was used to classify owner responses to questions regarding the progress of their puppy. For questions about the current status of puppies, possible responses included none, low, moderate, good, and excellent. For questions about the current status of puppies in relation to that of the past, options included much worse, worse, same, better, and much better.

Owners were also asked to report any behavior problems that were evident before the class or that arose during the classes. A behavior problem was defined as anything the owner perceived as such. This could be an actual behavior problem (eg, aggression, separation anxiety, fear, or phobia) or other behavior that was unacceptable to the owner (eg, barking, house soiling, or unruly behavior). Owners were also asked to rank the severity of any behavior problem on a 5-point scale and report any changes (improvement or deterioration) in that behavior throughout the classes. No professional management was offered (by the investigator or trainers) to owners to solve these problems other than what was routinely taught during the puppy classes.

Degree of socialization was measured 1, 3, 6, and 12 months after the classes ended. Telephone interviews with owners were conducted by means of a questionnaire. Again, responses were classified on 5-point scales. Responses to questions regarding behavior in familiar or unfamiliar situations were limited to very bad, bad, impartial, good, and very good. Those regarding behavior when meeting unfamiliar dogs or people were limited to very nervous, nervous, calm, friendly, or very friendly. Owners were also asked to classify the length of time that their puppy took to relax in unfamiliar situations, with possible responses of cannot relax, very long (> 15 minutes), long (> 10 minutes), few minutes (about 5 minutes), or immediately.

During the telephone survey portion of the study, owners and the person administering the questionnaire (a veterinary technician) were unaware of the treatment group to which puppies had been allocated. This protocol was used because, after the results were tabulated and analyzed at the end of the puppy classes, the primary investigator was made aware of treatment allocation so that it could be determined whether the DAP collars had been effective and whether any additional follow-up was warranted.

Statistical analysis—Before effectiveness of DAP was analyzed, dogs in the DAP groups were compared with those in the placebo groups with respect to distributions of sex and size (small vs large breed) by means of a 2-tailed Fisher exact test. Data on quantitative characteristics of dogs (age and scores for learning in class, excitability, learning at home, and fear), usefulness of DAP collars, and owner satisfaction did not meet the assumption of normally distributed responses; therefore, the nonparametric Wilcoxon rank sum test was used to compare data between dogs in the DAP groups and those in the placebo groups. Since there were no significant differences in sex, age, size, and number of puppies among each of the 4 groups (P > 0.10), the data were combined into 2 groups: a DAP group and a placebo group.

Puppies were expected to develop and learn more cues and improve their performance during their lives regardless of whether they attended a puppy class or wore a DAP collar. Therefore, a progress factor was added to scores at each week for responses to questions that could have reflected the expected development of puppies, regardless of whether they were enrolled in classes. The size of the progress factor was weighted according to week of the study (eg, the progress factor for week 0 was 0, and that for week 3 was 3).

Efficacy criteria (ie, degrees of fear, excitability, learning, and learning at home and usefulness of the collar) and the effects of each class were also analyzed. A 1-tailed Wilcoxon rank sum test was used to evaluate scores of learning, excitability, learning at home, fear, DAP collar usefulness, and owner satisfaction with their puppy at each evaluation, and for the follow-up survey on socialization. For all analyses, the significance threshold was set at 5%. Commercially available software^b was used for all analyses.

Results

Animals—Only 6% (3/48) of dogs did not achieve the attendance criteria and were excluded from the study. Two puppies in the placebo groups failed to complete classes (1 because of its owner's choice and the other for unexplained reasons), as did 1 puppy in the DAP group (after injury in a car accident). Thus, the 45 puppies that completed trial were distributed into 4 groups: small- (n = 15) and large- (9) breed dogs that received DAP collars (DAP groups) and small- (8) and large- (13) breed dogs that received placebo collars (placebo groups).

In the DAP groups, 15 puppies were male and 9 were female; in the placebo groups, 10 puppies were male and 11 were female. Breeds of dogs classified as large (≥ 25 kg) included mixed breed (n = 5), Labrador Retriever (4), Boxer (3), German Shepherd Dog (3), Rottweiler (2), Springer Spaniel (2), Golden Retriever (2), and Siberian Husky (1). Breeds of dogs classified as small (< 25 kg) included mixed breed (5), Miniature Pinscher (3), Yorkshire Terrier (3), Bichon Frise (2), Miniature Poodle (2), Havanese (2), Jack Shih Tzu (2), West Highland White Terrier (2), Chihuahua (1), and Jack Russell Terrier (1). At the starting point, the mean age of dogs in the DAP groups was 13.6 ± 3.3 weeks for small-breed dogs and 13.0 ± 1.5 weeks for large-breed dogs. In the placebo groups, mean age of dogs was 13.9 ± 1.9 weeks for small-breed dogs and 12.7 ± 1.6 weeks for large-breed dogs. Dogs in the DAP and placebo groups were not significantly different with respect to age, breed, size, or sex. At the beginning of the study, dogs in the DAP and placebo groups were also not significantly different with respect to scores for learning at home, excitability, degree of fear, and owner satisfaction (Table 1).

Effects of DAP—The amount of learning in class was measured from the second week of classes (week 1) to the eighth and final week of classes (week 7). Scores were similar in both groups throughout the classes, with no significant differences between groups except at the end of week 2 (after the third class), at which point the scores for dogs in the DAP groups were significantly (P < 0.04) more improved than scores for dogs in the placebo groups. Compared with scores for previous weeks, scores for dogs in the DAP groups were significantly (P < 0.02) more improved than scores for dogs in the placebo groups. In all other weeks, no significant improvement in scores from those of previous weeks was detected.

At various points from weeks 3 through 7 as well as at the final evaluation, owners of puppies in the DAP groups reported significantly lower degrees of excitability than did owners of puppies in the placebo groups (Figure 1; Table 2). The investigator and trainers also recorded better performance during training (more immediacy, requiring less repetition of commands to achieve success, and higher frequency of success) among dogs in the DAP groups. The trainers and investigator, who were unaware of the treatment groups to which dogs had been assigned, believed this improvement was attributable to a decrease in excitability and fearfulness in these dogs. The owners and puppies in the DAP groups appeared more relaxed, and the trainers spent less time explaining new training tasks.

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Graph of median excitability (anxiety) scores for puppies that wore DAP collars (n = 24; black bars) or placebo collars (21; white bars) and attended puppy training classes for an 8-week period. Degree of excitability was measured before the first class (week 0) and after the 7 subsequent classes. A final assessment was made after the eighth class to measure overall change in degree of excitability, compared with that before classes began. A 5-point scoring system was used (0 = none; 1 = low; 2 = moderate; 3 = high; and 4 = very high). *Values for DAP and placebo groups are significantly different at the time point indicated.

Citation: Journal of the American Veterinary Medical Association 233, 12; 10.2460/javma.233.12.1874

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Except for the final evaluation at week 7 (the final class), dogs in the DAP and placebo groups improved similarly with respect to learning at home throughout the course of the study. The final evaluation, which summarized the effects of the entire course, revealed that dogs in the DAP groups improved more than dogs in the placebo groups.

At various points from week 1 to 4 and at the final evaluation, owners of puppies in the DAP groups reported significantly lower degrees of fear than did owners of puppies in the placebo groups (Figure 2; Table 3). The trainers and investigator also noticed less shyness and better and more successful interaction among the puppies in the DAP groups, compared with the same traits in puppies in the placebo groups.

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Graph of median fear scores for puppies that wore DAP collars (n = 24; black bars) or placebo collars (21; white bars) and attended puppy training classes for an 8-week period. Degree of fear was measured before the first class (week 0) and after the 7 subsequent classes. See Figure 1 for remainder of key.

Citation: Journal of the American Veterinary Medical Association 233, 12; 10.2460/javma.233.12.1874

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Owners rated the usefulness of collars equally for puppies in the DAP and placebo groups at most time points, except at week 5 (after class 6), at which point owners of dogs in the DAP groups reported higher satisfaction scores (Table 4). All owners reported similar degrees of satisfaction with their puppies throughout the classes.

Forty-two percent (10/24) of owners of puppies in the DAP groups reported ≥ 1 of the following behavior problems before classes began: fear (n = 5), separation anxiety (3), excessive barking (2), aggression (2), unruly behavior (1), nipping (1), and submissive urination (1). Thirty-eight percent (8/21) of owners of puppies in the placebo groups also reported ≥ 1 problem as follows: nipping and biting (2), separation anxiety (2), aggression (2), unruly behavior (1), and house soiling (1). By week 7, all the problems were resolved in the DAP groups except for 1 puppy with fear aggression, whereas in the placebo group, 2 puppies were reported to have problems with fear and 1 puppy was reported to submissively urinate.

Training—Classes were designed to last 60 minutes, including 15 minutes for playtime. During this playtime, the investigator and trainers noticed that dogs in the placebo groups were interacting less frequently and less successfully than were dogs in the DAP groups. Most of the play sessions lasted < 10 minutes in the placebo groups. In the DAP groups, most play sessions lasted ≥ 15 minutes, and the classes lasted > 60 minutes (mean class time, 78 minutes) because more owners stayed after the class ended to allow their puppies, which were still interested in playing, to interact with other puppies. Puppies in the DAP groups appeared more relaxed next to each other and played together longer, and more puppies joined the play groups, compared with puppies in the placebo groups. On the other hand, during classes for dogs in the placebo groups, some puppies did not engage in play with other puppies, and by the end of the classes, some of the puppies did not play with others or had signs of fear and aggression toward other puppies. As the classes progressed, more and more puppies in the DAP groups took active part in playing with each other. In the last 4 (out of 8) sessions, all puppies in the DAP groups played. This is in contrast to the behavior of puppies in the placebo groups, in which a mean of 3 puppies did not interact with other puppies at all.

The follow-up telephone surveys conducted at 1, 3, 6, and 12 months following the last class revealed that dogs in the DAP groups had a significantly (P < 0.01) higher degree of socialization, compared with dogs in the placebo group. Dogs in the DAP groups had better scores for all 4 measures of socialization (behavior in familiar situations; behavior in unfamiliar situations; behavior when meeting unfamiliar people, dogs, or both; and time to relaxation in unfamiliar situations), which were combined for statistical analysis at each time point (Figure 3). Seventy-nine percent (19/24) of owners of puppies in the DAP groups reported good to very good results for all measures, whereas 52% (11/21) of owners of dogs in the placebo groups reported negative results.

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Graph of median socialization scores for puppies that wore DAP collars (n = 24; black bars) or placebo collars (21; white bars) and attended puppy training classes for an 8-week period, as assessed at various time points during the 12 months after classes concluded. A 5-point scoring system was used (0 = very bad; 1 = bad; 2 = impartial; 3 = good; and 4 = very good). See Figure 1 for remainder of key.

Citation: Journal of the American Veterinary Medical Association 233, 12; 10.2460/javma.233.12.1874

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Discussion

Although puppy owners were allowed to choose the night on which they wished to attend puppy classes, the trainers, owners, and investigator were unaware of which collar (DAP or placebo) puppies were wearing. Analysis of the data revealed that the groups of puppies that wore DAP or placebo collars were not significantly different with respect to values of variables (amount of learning at home and degrees of fear and excitability) measured before the start of the first puppy training class. They were also similar with regard to age, sex, size, and class size. Although breed-specific behavior may have had some influence on the outcomes measured, there was a wide range of breed types in each class and no breeds appeared to be overrepresented within any particular group. In addition, puppies were < 15 weeks of age when enrolled in classes, and most heritable and breed-specific behaviors do not begin to emerge until dogs reach sexual and social maturity.¹⁷ For example, in 1 study¹⁸ of police dogs, aggression could not be predicted until dogs were 9 months of age.

One limitation of the study reported here was that puppies could be enrolled in classes at the training school up to 15 weeks of age. Therefore, although it might be ideal for all puppies to start training prior to 12 weeks of age, older puppies were accepted, provided they had been recently adopted and had not had any formal training. Forty-one percent of the puppies in the DAP groups and 38% of puppies in the placebo groups were 12 weeks old or younger. That said, comparison of ages of puppies at enrollment among the different groups revealed that ages were not significantly different.

One difference between puppies in the DAP and placebo groups was that initially, there were more behavior problems among puppies in the DAP group. However, because all of the puppies enrolled in the study at 10 to 15 weeks of age had similar degrees of fear, excitability, and learning ability, the puppies were similar with respect to the variables that could be used to specifically compare the effectiveness of DAP collars with that of placebo collars with regard to puppy training. Another limitation of our study was that the puppies were allocated to groups in which all dogs wore either the DAP or placebo collar, and classes for these dogs were held on different days. However, this strategy was necessary to ensure that puppies in the placebo groups were not exposed to DAP.

For the purposes of our study, during the statistical analysis, data from puppies in the small- and large-breed DAP groups were combined for comparison with combined data from puppies in the small- and large-breed placebo groups. We believed this approach was justified because differences in the effectiveness of DAP related to size or breed of dog have not been identified to date.¹⁹

Amounts of learning in class were similar between the groups of puppies. We expected that all puppies would learn new cues during the classes through the proper use of repetition and reinforcement if the owners remained active participants in the classes and training. In general, one can expect some minor differences among puppies during a particular class; however, in the long term, the differences are likely to be subtle as long as training continues. During classes, the trainer is present to help the puppy and owner learn cues and reinforce and shape desirable outcomes. Because learning is based on repetition, consistency, and reinforcement, it was not expected that DAP would have a significant effect on amount of learning; however, use of DAP have improved learning and training by reducing the degrees of excitability (anxiety) and fear.⁵

Degrees of fear and excitability were significantly lower in puppies in the DAP groups, compared with values for puppies in the placebo groups, and puppies that wore DAP collars performed better than puppies that wore placebo collars. This improvement in performance was apparent in the readiness and eagerness of the puppies to interact with their owners and the other people and puppies in the class. In turn, owners of puppies in the DAP groups reported a higher degree of satisfaction with their dogs, although the difference between the DAP and placebo groups was not significant. Greater success in puppy socialization classes leads to better and stronger bonds between owners and puppies and higher retention of the dogs later in life.⁴ Therefore, veterinarians should dedicate some time and effort during puppy visits to discuss socialization and suggest that the owners take their puppies to classes to maintain or strengthen the bond and decrease the likelihood of relinquishment to shelters.²⁰

All owners in the present study started the classes with the same purpose of training and socializing their dogs. As classes progressed, it became evident that owners of dogs that performed well reported a high to very high degree of satisfaction with their dogs and were more likely to reinforce their dogs regularly. As a result, these classes were more interactive and lasted longer to allow puppies to play together. At the time investigators were made aware of the groups to which puppies had been assigned, it was determined that the longer and more interactive classes were those involving the DAP versus placebo groups. In fact, puppies in the DAP groups appeared more relaxed next to each other, played together longer, and were more likely to engage in play, compared with puppies in the placebo groups. Because DAP reduces anxiety and fear in puppies, it was expected that puppies in the DAP groups would be more relaxed, react better to new experiences and stimuli, and be easier to control and reinforce than would puppies in the placebo groups.

Some decline in sociability is to be expected in all dogs because the sensitive period for socialization begins to decline at 12 to 14 weeks of age,¹ and many dogs will have fewer interactions with other dogs after classes have ended. However, as indicated by the results of the follow-up telephone survey, dogs from the DAP groups were more sociable than dogs from the placebo groups. By helping dogs adapt to new people, pets, and situations, use of DAP can help prevent future problems related to insufficient or inadequate socialization. Although other factors that may have influenced degrees of fear and socialization in dogs could not be controlled after the end of puppy classes, the significant improvement in socialization among dogs from the DAP groups suggests an influence of DAP in puppy classes on socialization outcomes up to 1 year after classes.

Behavior problems identified by owners were recorded at the first class, but no behavioral assessment took place and no specific behavioral or training advice was offered with respect to these problems. At that time, owners reported a wide variety of problems, including unruly behaviors, house soiling, separation anxiety, and aggression. Information on the intensity of these problems was not requested. Managing behavior problems was not an objective of the study reported here; however, by the end of classes, puppies in the DAP groups reportedly had fewer behavior problems than puppies in the placebo groups, which was likely a result of the combined effects of reduced excitability and fear, resulting in more successful training by owners.

Despite improvements in degrees of excitability and fear and the reduction in behavior problems, there was no significant difference in owner satisfaction with puppies between the placebo and DAP groups. This might be expected because all owners reported that they had obtained their puppy as a companion. Regardless of whether DAP collars are used, attending puppy classes and training with positive reinforcement should help to maintain or improve the bond between dogs and their owners.

In the study reported here, DAP was useful in reducing degrees of anxiety and arousal in puppies attending puppy training classes. Compared with puppies that received placebo collars, puppies that received DAP collars were less fearful, learned better, and had fewer behavior problems. Furthermore, use of DAP during the period in which classes were attended had a long-term effect on the sociability of dogs up to 1 year after classes concluded.