Dogs (Canis familiaris) have been human-beings' companions for over 12,000 years (MacArthur, 1987). In the laboratory, this potential for developing a close relationship with people may be realized through appropriate socialization of the animal at an early age. As well, most breeds of dogs used in research, teaching and testing are naturally gregarious and seek the companionship of other dogs (MacArthur, 1987; Beaver, 1981). This tendency is also seen in packs of feral or wild dogs travelling together (Dunbar, 1979). Therefore, unless contra-indicated by the protocol, medical condition, or the animal's aggressiveness, dogs should be paired or group housed with conspecifics in cages or runs, with space adequate for active normal behaviour. If this is not possible, dogs should be released at regular intervals into space adequate to permit this normal species-typical behaviour.
Social rearing of puppies is the most effective means of ensuring compatible conspecific behaviour as adults (Fox, 1972). Moreover, dogs that have been handled as puppies show greater resistance to stress and greater disease tolerance than those which are not handled (Fox, 1975).
The appropriate maintenance of
dogs will be discussed under breed differences, criteria for assessing
well-being, housing, socialization to people, and enrichments.
2. Breed Differences
The differences in size between Newfoundlands and Chihuahuas represent some of the extremes seen among the many breeds of dogs. These differences include not only morphology, but also temperament (e.g., terriers vs. labrador retrievers), conformation (e.g., beagles vs. greyhounds), urea metabolism (dalmatians), development of behaviour patterns (MacArthur, 1987) and other important considerations. Although every dog belongs to the single species (Canis familiaris), each breed has specific behavioural and social needs.
Interbreed morphological differences become important in selection of proper cage size (even though they have the same body weight, long, lean dogs are likely to require different cage sizes than short, stocky dogs). The decision to group house will depend to some degree upon breed differences. Much can be learned appropriate to the well-being of dogs from a basic knowledge of breed-typical behaviours; however, attention to the uniqueness of each individual animal is the only way in which well-being can be assured.
In addition to understanding
breed differences, an understanding of intrabreed differences, which are
the natural outcome of environmental and genetic factors, is also of great
value. Litter mates, even when reared under the same conditions, may behave
3. Criteria for Assessing Well-being
Evaluation of animal well-being includes both engineering (environmental) standards (e.g., minimum cage size, temperature, light cycles, etc.) and performance or outcome measures (McCarthy, 1989) standards (the dogs' general state of health and their compatibility in social groups and with people).
The well-being of dogs is dependent on a number of factors which include: training and dedication of the scientific, animal care, and veterinary staff; a facility in compliance with this Guide; observations of the animal's physical health (does it appear healthy, alert, active?); observation of the dog's behaviour; pair or group housing of compatible animals; and socialization to people.
a) Clinical Observations
Housing should facilitate social group formation, human interaction, comfort, and sanitation. The use of modular cages or runs that can be converted to accommodate either pairs or groups of dogs is desirable.
Hite, Hanson, Conti et al. (1977) and Hughes, Campbell and Kenney (1989) discuss the effects of cage size on beagles (the most commonly used purposebred dog). Caging should permit ready access by personnel and permit visual, olfactory, and auditory contact with other dogs.
Resting boards made of non-conductive, non-permeable materials should be provided to permit animals to escape the floor, especially when temperature control and wetting may be a problem.
i) Social housing
Social housing is desirable for most breeds of dogs. Centuries of interaction with people and other dogs have developed species-typical behavioural patterns, which must be understood in order to evaluate and provide for their well-being (Beaver, 1981). Some breeds of dogs (e.g., hounds) are highly social; others such as terriers are not (Beaver, 1981). Single caging for most social breeds may be stressful.
Movement of an individual(s) away from compatible animals can be disruptive. Dogs that are removed from a social group (by virtue of health, protocol, or aggression) should remain in the same room, as close to the same social group as possible, and should be returned to the group as soon as possible. When the group is stable, positions within the room should not be changed without cause.
ii) Single housing
For those animals comfortably adapted to solitary living, introducing cagemates may induce distress. In these circumstances, exceptions to social housing may be appropriate, especially where human companionship is provided and they are in visual and auditory contact with other dogs.
If dogs must be housed singly, they should be in visual, auditory and olfactory contact with others in the room. It is likely that multiple social groups exist within such a room, with the most stable groups consisting of individuals immediately adjacent to or across from each other.
It should be remembered that
dominance can be expressed across the aisle, so that an animal removed
from a cagemate because of dominance aggression should not be placed directly
across the aisle from its original cagemate, but moved to a location away
from the overly dominant individual.
5. Socialization to People
Of all the common laboratory species, dogs are the most highly domesticated and adapted to live in intimate association with people. Socialization creates an attachment and trust of people, which assists in the development of coping strategies that serve to bridge periods of adaptation to new procedures and environments, thereby reducing stress and experimental variability.
Without early exposure to people (i.e., socialization), dogs rapidly become fearful of humans and manifest fear and distress in a variety of physiological and behavioural ways (e.g., "fear biting") (Beaver, 1981), all of which are incompatible with their well-being and can influence the reliability of research data derived from them.
The dog's ability to cope when a person enters the scene, or its environment changes, is a key criterion to well-being (Dunbar, 1979). Coping connotes the ability of the dog to adapt to stresses with minimal behavioural or physiological alteration (Archer, 1979).
Therefore, all dogs used in a facility, for whatever purpose, should be socialized to people, (either in the facility or by the supplier), or serious consideration be given to their euthanasia or use in acute non-survival studies. Socialization (handling by people) should take place when pups are between 6-10 weeks of age (Wolfle, 1989a, 1989b; MacArthur, 1987; Fox, 1975). A number of other investigators believe the socialization period should extend to at least 12 weeks (Pfaffenberger, 1963; Bateson, 1987; Vanderlip, Vanderlip and Myles, 1985a, 1985b; Scott and Fuller, 1965). Fox (1968, 1990) contends that puppies deprived of human contact until after 10 weeks of age will be very difficult to handle later in life.
Adult dogs that demonstrate lack of socialization should not remain in the facility any longer than it takes to determine that the behaviour is unlikely to respond to remedial socialization, which, in any event is time and energy consuming and not at all sure of success (Dunbar, 1979). Such dogs should be either euthanized or used immediately in an acute, non-survival study. Socialization should be considered a critical part of every breeding program, and when animals are purchased from a supplier, socialization should be written into contract specifications.
Human/dog interactions will ensure continuation of the benefits gained from socialization. Quantification of contact during the socialization period, in terms of specific frequencies or durations, is less important than the quality of the interaction. Puppies are susceptible to attachment to humans or other animals. Thus, repetitive interaction with people during this period is more important than the exact nature, frequency, or duration of the interaction.
Wolfle (1990) described the socialization of large numbers of foxhound puppies with only five minutes per puppy per week. However, it should be noted that this was a complex, rich, bi-weekly socialization procedure where littermates were treated as a group and thus each pup benefitted from the interaction of people with the littermates. Nevertheless, it is clear that the amount of "hands-on" time required to socialize large numbers of puppies does not seem to be critical, and should be possible to accomplish with existing staff in most facilities.
Through observation, it should be established whether each dog in a social group is behaving normally (Beaver, 1981). By having a variety of people participate in the socialization of each dog and by reinforcing their socialization as adults, the problem of over-attachment to an individual (person) can be avoided.
Housekeeping routines should
include recognition of each dog as the technician works about the room.
Moments taken to speak to and pet the dogs will be repaid through reduction
in the dogs' anxiety and physiological variability (Wolfle, 1990, 1985,
1989a, 1989b). The effects of animal caretaker styles may affect the animal
(Fox, 1986) and thus experimental results.
6. Enrichment Devices (Artificial Appliances)
"Enrichments," often in the form of toys or other appliances, are frequently given to dogs to produce a desired change in behaviour. For example, abnormal or persistent grooming may be moderated by giving the dog rawhide or other treats on which to gnaw; however, this should be done only with the knowledge of the facility manager and investigator. Beaver (1989) notes that dogs respond well to running through mazes as a means of environmental enrichment.
Music has long been used to reduce
stress in many laboratory animal facilities (Line, Clarke, Ellman et al.
1987) and dairy barns (Ewbank, 1968), (perhaps because of its initial stress-reducing
effect on the attendant). However, few definitive data exist to recommend
its use for dogs. If used, the volume should be placed at conversational
levels. Levels exceeding 85 db for a sustained period may cause auditory
damage. It should also be remembered that many laboratory animals, including
dogs, are able to hear frequencies above what humans can hear (Dunbar,
1979). If violin music, for example, is played at high volume, dogs may
be in acute discomfort. Conversational (talk show) radio sound may accustom
the animal to the human voice.
Exercise for dogs has recently been mandated in American law which requires "that research facilities shall establish, in consultation with the attending veterinarian, written procedures and systems for exercise of dogs..." (USDA, 1989).
Dr. Dale Schwindaman, Assistant Deputy Minister for Regulatory Enforcement, Animal and Plant Health Inspection Services, U.S. Department of Agriculture, has stated that, in looking at exercise and socialization requirements, it may turn out that social contact with other dogs or with humans in the case of singly housed animals is more important than exercise. He reports that it has been proposed that, in addition to housing in compatible groups, the ability to see and hear other dogs will be required. Singly housed animals would receive positive physical contact with humans. Any exceptions to the requirement for exercise and socialization would have to be approved by the Institutional Animal Care and Use Committee (IACUC). It has also been proposed that animals held in (space that is) less than what is required for permanent housing as mandated by the Guide for the Care and Use of Laboratory Animals (USDHHS, 1985) would have to be released for exercise for at least thirty minutes daily (Schwindaman, 1990).
Scientific data have indicated that cage size had no significant effects on hematologic or serum biochemical values of purposebred beagles; that the dogs had little inclination to exercise when released alone into an exercise area, unless humans were present in the room; and that even a moderate exercise program had no demonstrable effect on biochemical parameters such as hematology, clinical chemistry or indicators of stress (Campbell, Hughes, Griffen et al. 1988; Hughes, Campbell, and Kenney, 1989; Campbell, 1990).
Studies demonstrated that on the average, dogs spend only 0.5 to 1.5 hours daily in any type of activity, regardless of the housing system. Most of the dog's activity takes place during the morning hours when there is the greatest amount of human activity in the area. Providing increased human contact will improve the handling and behavioural characteristics of the dog, but not its activity, because dogs that do not have enhanced human contact may move around the cage in an effort to attract attention (Hughes and Campbell, 1990). These authors contend that they have shown that "dogs are basically lazy. They do not like to exercise and have no particular inclination to run about an area." Fox (1986) reports that dogs that are well-fed and content do not exercise routinely.
Although, unlike the U.S., no legal requirements for the exercise of dogs exist in Canada, the concept of exercise, and perhaps more importantly communal housing and socialization of the animal, both with conspecifics and humans, is considered of great importance by the CCAC. Institutions are being asked to furnish documentation of ACC approval for any dog housed individually. Increasingly, the provision of environmental enrichment, in its various forms, will be strongly recommended by the CCAC.
In conclusion, it should be remembered that, as Erwin (1985) advised, reactions of animals to any type of environmental enrichment should be monitored to determine whether the desired outcome is achieved.
Beaver (1989) reminds us that
studies have not determined the amount of activity that is actually beneficial
to any species. Neither has it been shown whether stereotypic behaviour
is beneficial or harmful (Fox, 1986). Much knowledge of animal behaviour
remains to be garnered and established in order to produce an environment
that will enhance the dog's well-being.