Breed considerations

The primary focus of selective breeding was to develop dogs that were best able to perform specific working functions such as herding, hunting, retrieving, or protection as well as more specific tasks such as search and rescue. Many dogs continue to be bred for working ability or for more specialized tasks such as therapy and assistance dogs, while others are bred specifically for show. Therefore there can be dramatic differences between the behavioral needs and temperament of working lines and show lines.

By selecting a mixed-breed animal from a shelter, an abandoned animal can be saved from death, and the initial cost is very reasonable. One can even argue that there are genetic advantages to obtaining mixed-breed animals (“hybrid vigor”). Selective breeding has produced dogs with a range of extreme proportions from giant breed to toy and from brachycephalic to chondrodysplastic, which in turn contributes to health problems. Furthermore, inbreeding increases the likelihood of heritable diseases of both health and behavior.^3,4 Eliminating genetic defects requires the identification and removal of affected individuals from the breeding pool, yet ironically, removal of these individuals further narrows the breeding pool. Therefore, outbreeding or even cross-breeding may be the most practical solution. Although kennel clubs and breed associations would be resistant to cross-breeding, this is the very way that today’s breeds were originally developed.⁵

Therefore the issues with respect to breed selection are: (1) whether the prospective owner wants a purebred pet; (2) understanding the function for which the breed was originally developed; (3) whether the dogs are bred for work or show; (4) the potential health and behavior issues of the breed; and (5) whether the dog is likely to be suitable to the owner’s home, lifestyle, and goals of pet ownership. Despite the downsides to inbreeding, predictability is likely to be highest for size, coat, function, health, and behavior from selecting a purebred dog with known parentage (Box 3.1).

With well over a thousand breeds of dogs to choose from, it is advisable that the owners first narrow the selection process down to a few breeds that appeal to them before attending a selection consult at your clinic. This can be accomplished by providing suggested reading and websites (see Appendix C, form C.1, client form #13, printable version available online), as well as having the client attend some dog or cat shows to see a variety of breeds and meet some breeders or handlers. The owners might also be encouraged to contact groomers, trainers, or kennel clubs for additional input. The websites of national kennel clubs and veterinary organizations can provide useful information on pet selection for your clients. Another option is to visit one of the computerized selection services on the internet (Table 3.1).

Two of the most important aspects of pet selection include determining the family’s reason for owning a pet as well as any limitations for owning certain types of pets. This may not only help to choose the right type of pet but also eliminate certain breeds from consideration (Table 3.2). For example, a family that is interested in obtaining a pet primarily for companionship might be interested in engaging in agility training, flyball, or herding trials, or might be a sedentary couple or incapable of providing intensive exercise or training. Similarly, potential pet owners may want to consider breeds for a particular type of work (herding, hunting, household protection), for a particular size range, or because a family member has allergies.

Table 3.2 Breed tendencies that might be important in the selection process

^*Not necessarily nonallergenic or hypoallergenic, but tends to shed less and/or produce less dander. However, studies have demonstrated that there does not appear to be any significant difference in the levels of the major dog allergen (Can f 1), regardless of breed.¹

¹Nicholas CE, Wegienka GR, Havstad, SL, et al. Dog allergen levels in homes with hypoallergenic compared with nonhypoallergenic dogs. Am J Rhinol Allergy 2011;25:252–256.

If an owner then has a query about a breed with which you are less familiar, be prepared to do the research before you make your recommendations. If you take the time to document pros and cons for each breed as you experience or read about them, eventually you will have an impressive array of facts for the would-be owner. In addition, you should collect a good library of books, journals, and websites since the owners will need information on:

Although there are a number of books that provide breed behavioral profiles (see recommended reading, below) there can be a great deal of variability between lines, across different geographical areas, and even between individuals within the same litter. Veterinarians should have some idea of the characteristics that are most predictable (e.g., watchdog ability in Rottweilers, vocalization in Siamese cats, and chase in herding breeds) and which traits are more affected by environment and training such as destructiveness and housesoiling. Veterinarians should also be cognizant of potential problems such as tendencies toward aggression, high activity level, fear, sensitivity to pain and noise, and specific conditions such as flank sucking in Doberman Pinschers, wool sucking in Siamese cats, spinning in bull terriers and impulse dyscontrol aggression in English Cocker spaniels and English Springer spaniels.

Pet age

Puppies less than 3 months and kittens less than 9 weeks are most receptive to socialization, adapting to new environments and habituating to new stimuli. Young pets may also be a better mix for families with existing pets. Conversely, puppies and kittens require a committed family to provide the appropriate time and energy to socialize properly and train the puppy or kitten at this highly impressionable age. Adult dogs and cats may already be insufficiently socialized or improperly trained so that problems may be difficult or impossible to correct. Adult pets may have difficulty adapting to an environment or social group that is dissimilar from their previous household. By comparison, adult pets may be able to handle longer owner departures, may present fewer problems with overexuberant play, nipping, and chewing, and may already have some basic training. In one study, owners reported more problems especially with respect to aggressive play when first adopting young cats compared to adult cats.⁶ In addition, while behavior assessment tests in young puppies and kittens may be poorly predictive of adult behavior, predictability may be greater when assessing older puppies and kittens and adult pets (see below).

Pet gender

Male dogs and cats are slightly larger in stature than females. Male dogs may mark, mount, masturbate, and display aggression toward other male dogs. Gonadectomy decreases gonadal steroid hormones and has been correlated with a decrease in sexually dimorphic behaviors.^2,7–11 Working dog trainability does not appear to be altered by gonadectomy in general, nor with the age of the dog at the time of gonadectomy.¹²

Neutering may affect a variety of behaviors but results of neutering studies have been somewhat conflicting. One study suggested marking, mounting, masturbation, and aggression toward other male dogs and territorial aggression might be prevented or reduced by castration.¹³ However, another study found no effect of neutering on intermale aggression, roaming, or mounting.¹⁴ One other study suggested that neutering does not appear to decrease the likelihood of aggression in male dogs, with perhaps the exception of some cases of territorial and intermale aggression.¹⁵

A study of pet dogs suggested that male dogs are more likely to score above the median on owner-directed aggression, and dogs that were neutered/spayed were less likely to score above the median on owner-directed aggression than intact individuals.¹⁶ A study found that the odds ratio of biting a member of the household was highest for neutered male dogs followed by neutered female dogs and intact male dogs, and the lowest level by intact females.¹⁷ Similar effects were seen for growling and possessive aggression.¹⁷ In another study, intact males were 1.68 (95% confidence interval (CI) 1.05–2.71) times more likely to bite than castrated males, but 0.80 (95% CI 0.55–1.14) times as likely to bite as intact females.¹⁸

Some studies suggest that spayed females are more likely to display certain types of aggression when compared with intact females.^19,20 An increase in reactivity toward humans with unfamiliar dogs and in aggression toward family members has been reported after ovariohysterectomy of bitches in several studies.^19–21 While the cause has not been determined, it may be due to a decrease in estrogen and oxytocin concentrations, both of which may have some antianxiety effects.²²

Ovariohysterectomy (spaying) of dogs and cats eliminates behaviors associated with estrus cycles and pseudocyesis in dogs. Castration of both dogs and cats reduces, but may not eliminate, sexual interest in females. Castration of male cats reduces urine odor and decreases sexually dimorphic behaviors such as fighting, spraying, and roaming, but has no effect on hunting.²³ However since the masculinization of the brain in males occurs prior to birth, male–female differences may persist even after neutering. For example, about 10% of spayed female cats and 5% of castrated males will mark territory with urine.^11,23

Recent reports have suggested other behavioral changes following gonadectomy. A large-scale study of dogs indicated that noise phobias may increase, while separation anxiety and submissive urination may be less frequent in dogs that were neutered before 5 months of age.⁸ Some studies suggest an increased frequency of separation anxiety in neutered pets.^24,25 In another study, neutered dogs were found to be more nervous or timid than sexually intact dogs, but they were also rated as less anxious and engaged in less destructive activity.²⁶

As we gather more information regarding how gonadectomy influences behavior, there is conflicting information and still many unanswered questions, with the situation seeming somewhat muddier rather than clearer.