Page 327 - Small Animal Clinical Nutrition 5th Edition

334 Small Animal Clinical Nutrition

ry performance. Dogs that are out of breath and are panting
Table 18-7. Disorders affecting olfaction in people.* excessively have reduced ability to detect scent (Gazit and
VetBooks.ir Disorder Effect on olfaction Terkel, 2002).
Adrenal cortical insufficiency
Absent or diminished
Allergic rhinitis Increased detection Physical Examination
Bronchial asthma Absent or diminished
Chronic kidney failure Absent or diminished During the physical examination, the veterinarian should eval-
Cobalamin deficiency Absent or diminished uate the dog’s general health, musculoskeletal soundness, hy-
Cushing’s syndrome Absent or diminished dration, upper respiratory function, cardiopulmonary function
Diabetes mellitus Absent or diminished
Head trauma Absent or diminished and body condition. A complete physical examination is crucial
Hepatic cirrhosis Absent or diminished because disease affecting any body system can impair perform-
Hypothyroidism Absent, diminished or distorted ance. For example, severe periodontal disease can cause suffi-
Nasal polyposis Absent or diminished
Upper respiratory infections Absent, diminished or distorted cient pain to affect food intake, thus causing a retriever to
Viral hepatitis (acute) Absent, diminished or distorted retrieve poorly or a greyhound to run poorly. Likewise any
*Many of these diseases would also be expected to cause similar injury or deterioration of the musculoskeletal system affects
problems in dogs. Adapted from: Schiffman SS. Taste and smell in
disease. New England Journal of Medicine 1983; 308: 1275-1279. performance. All major muscle groups and joints should be pal-
pated and moved through a complete range of motion during
the routine physical examination of canine athletes.
Certain infectious, traumatic, endocrine and metabolic dis-
Table 18-8. Drugs that can cause changes in the sense of
smell in dogs and people.* eases can affect olfaction. Table 18-7 summarizes diseases that
modify olfaction in people. Many of these diseases would be
Drug Effect on olfaction expected to cause similar problems in dogs. For example, viral
Amiodarone Abnormal sense of smell reported in 1 to 3%
of human patients upper respiratory infections (e.g., canine distemper), including
Amlodipine Disturbance of smell reported rarely in human intranasal inoculation with modified-live virus distemper vac-
patients; resolves after drug withdrawal cine will cause dysosmia (Myers, 1990). In a survey of field trial
Bromocriptine Olfactory hallucination in 9% of human
patients receiving 0.5 to 5 mg/day participants requesting information about the prevalence of
Cimetidine Decrease in olfactory acuity in human patients; anosmia in their hunting dogs, 85% of owners reported that
reported rarely they currently owned or had owned a dog with some loss of its
Dexamethasone Reduced olfactory acuity in dogs after only
one week sense of smell (Holloway, 1961). In another report, only 40% of
Doxycycline Loss or distortion of sense of smell in a small canine patients presenting with complaints of dysosmia actual-
number of human patients ly had dysosmia. In the remaining 60%, other disorders were
Nifedipine Disturbance of sense of smell in human
patients; rare and symptoms resolve after interfering with the dogs’ ability to hunt, including one dog
drug withdrawal with hip dysplasia (Myers, 1990).
Phenylephrine Decreased ability to smell in 1% of human Drugs can also negatively affect olfaction (Table 18-8). For
patients
*Adapted from: Bleasel AF, McLeod JG, Brown ML. Anosmia after example, corticosteroids reduce olfaction in dogs. The combi-
doxycycline use. Medical Journal of Australia 1990; 152: 440. nation of hydrocortisone plus desoxycorticosterone acetate
Ezeh PI, Myers LJ, Hanrahan LA, et al. Effects of steroids on resulted in a reduction of olfactory acuity after 18 days of
olfactory function of the dog. Physiology and Behavior 1992; 51:
1183-1187. Henkin RL. Drug induced taste and smell disorders: administration. Dexamethasone administration reduced olfac-
Incidence, mechanisms and management related primarily to tory acuity in dogs after only one week (Ezeh et al, 1992).
treatment of sensory receptor dysfunction. Drug Safety 1994; 11: These results are not surprising because Cushing’s disease
318-377. Levenson JL, Kennedy K. Dysosmia, dysgeusia and
nifedipine. Annals of Internal Medicine 1985; 1102: 135-136. results in reduced olfactory acuity and adrenal cortical insuffi-
Product Information: Amiodarone, 2004. ciency results in increased olfaction (Table 18-7). Many hunt-
ing dogs receive corticosteroid therapy for skin or muscu-
loskeletal disorders. On the other hand, zinc supplementation
homeostasis). High humidity impairs evaporative cooling thus is effective in some olfactory disorders (Henkin et al, 1999). In
adding to the work of heat excretion. Cold temperatures with- lieu of zinc deficiency, supplemental zinc is not warranted and
out exercise increase the energy requirement for thermogenesis. could be toxic when given at high levels (NRC, 2006).
For working dogs, cold environmental temperatures aid in Cardiopulmonary function is best assessed during routine
heat dissipation during exercise. Excitement or stress associ- physical examination by thorough auscultation of the heart and
ated with some activities increases body temperature and res- lung fields in a quiet environment. Energy balance can be eval-
piration, leading to greater requirements for energy, water uated by body condition scoring. The body condition score
and perhaps electrolytes. Stress may also negatively affect (BCS) is an indication of fat mass. If dietary energy intake is
food intake. Geographic factors such as high elevation, less than energy needs, fat mass declines and BCS decreases.
changing elevation (running up and down hills), bodies of Conversely, if intake exceeds requirement, fat mass and BCS
water (swimming) and the presence of sand or tall grass increase. Chapter 1 describes body condition scoring in detail.
underfoot can increase workload.These factors are important A BCS of 2.5/5 to 3.5/5 is normal for most pets and for many
to consider for their potential effects on exercise and olfacto- canine athletes. However, a much leaner body composition is