Page 316 - Small Animal Clinical Nutrition 5th Edition

Feeding Working and Sporting Dogs 323

km/hr). At the other extreme is the sled dog, which is capable
Table 18-3. Various scent-detection activities conducted by
VetBooks.ir between these extremes is a plethora of different kinds of work- Brown tree snake detection
of running vast distances, day after day, in arctic conditions. In
working and sporting dogs.
ing, hunting and sporting dogs that participate in a wide range
of athletic activities (Table 18-1). Cadaver detection
Conservation work
The American Kennel Club lists 26 sporting breeds, 18 Drug detection
herding breeds and 25 breeds of working dogs; however, it is Explosives detection
Fire accelerant detection
difficult to quantify how many of these dogs actually participate Game hunting
in athletic events (American Kennel Club, 2007). Eighty dif- Identification of individuals
ferent breeds of hounds are found worldwide and all these Pipeline leak detection
Search and rescue
breeds were originally hunting dogs. In addition, there are 13 Termite detection
sight hound breeds, 49 herding or shepherd dogs and 31 recog- Tracking for work or sport
nized terrier breeds (Palmer, 1994; van Lier, 1995; van War dogs
Leeuwen, 1995). Another classification system lists 91 hounds,
43 working breeds, 44 herding dogs, 49 gun dogs and 31 terri-
ers (Palmer, 1994). received in their absence. The sender must be present for visu-
Scent-detection type working dogs are employed by many al or auditory signals to be sent, but an odor persists for min-
government agencies including those involved in national utes to many days after the sender has gone (Houpt, 1998).
defense, customs service and border patrol. Additionally, in the Olfactory cues may help newborn puppies locate their mother
United States, more than 28,000 dogs work for state and local and its teats (Houpt, 1998a) and later might confer survival
law enforcement agencies. Numbers of active scent-detection advantages by promoting the acquisition of information about
type sporting dogs are difficult to document. In the United safety of different foods (Hepper and Wells, 2005).
States, survey results from one publisher estimate that readers Scent-detection ability is important to the function of many
of their hunting magazines own more than 700,000 active classes of sporting and working dogs. Based on tomb evidence,
a
hunting dogs. These same readers spend 150 to 200 hours per the use of dogs as chemical detectors dates back to their use as
year training their dogs and 40 days per year hunting in the hunting dogs 12,000 years ago (Furton and Meyers, 2001).
field with their dogs. In the United States, the National Today many scent-detection dogs do potentially life-saving
Greyhound Association registered about 26,000 greyhound work including detecting explosives, leading search and rescue
puppies per year in 2004 and 2005 and about 22,900 in 2006 teams, finding and detaining potentially dangerous criminals or
(National Greyhound Association, 2007). There are 37 dog alerting to the presence of enemies. Interestingly, with minimal
tracks in 14 states. b training, dogs are reportedly able to closely match biopsy results
Because dogs participate in a wide variety of working and in distinguishing between normal controls and lung and breast
sporting activities, and the level of participation varies from cancer patients by sniffing breath samples (McCulloch et al,
full-time athlete to intermittent activity, it is difficult to assess 2006). Dogs can also distinguish patients with bladder cancer
how much of the canine population participates in sporting and on the basis of urine odor. Apparently tumor-related volatile
working events. It is clear, however, that large numbers of dogs compounds are present in the urine, imparting a characteristic
participate in these activities. odor signature (Willis et al, 2004). Table 18-3 includes various
activities in which scent-detection dogs are used.
A review of the physical and chemical aspects of scent and
OLFACTORY PHYSIOLOGY the functioning of the olfactory system under different condi-
tions sets the stage for understanding how exercise training and
Olfaction is a very important special sense for dogs. Besides the proper nutrition can affect olfactory performance and scent
obvious value of facilitating obtaining prey, olfaction is signifi- detection.
cant in the overall communication process of canids. For dogs,
communication is fundamental to maintaining affiliations, Physics and Mechanics of Scent
reducing competition and identifying individuals (Simpson, The following discussion pertains primarily to scent trails from
1997). Urine scent marking by dogs is one example. It is animals or people. However, much of the information also
thought that a dog can identify the sex and even specific indi- applies to odors from inanimate and/or stationary objects.
viduals from the odor of another dog’s urine (Houpt, 1998). There are thought to be two general types of odors that are left
Urine is not the only olfactory cue for dog-to-dog communica- on a scent trail: individual odor and contact/disturbance odor.
tion. Anal gland and ear secretions are also thought to function Sources of individual odors could be skin cells, glandular secre-
in individual identification. Common greeting behaviors for tory products (sebaceous, apocrine and eccrine secretions) and,
dogs include sniffing under each other’s tails and investigating in the case of people, the smell of their clothes, deodorants,
odors of each other’s ears (Houpt, 1998; Fox and Bekoff, 1975). soap, etc. Contact/disturbance odors are generated as an animal
Also, as writing is to people, dogs can use olfaction-based com- or person walks over the ground. In the process, their footsteps
munication to send a message that can be transmitted and disrupt the surface, crushing vegetation, soil and other materi-