Senior Pets

October 15, 2011 at 3:16 PM

Senior Pets


        As Fall comes around it’s a good time to think about our senior pet friends, as it’s at this time when their aches and pains become more noticeable.


          It’s tough to define a senior dog or cat simply on the basis of chronological age. Generally, an animal is considered to be aged, mature, senior or approaching the golden years when it becomes less active and develops age-related physical and behavioural changes. In general, animals 7 years of age and older are considered at risk for age-related problems (a time when many age-related disorders and diseases are beginning to be observed).


Results of several studies summarising the age at which animals become senior:

Size of pet

Age considered senior

Average lifespan

Maximum lifespan


7-12 years

14 years

39 years

Small dog

7-13 years

13 years

29 years

Medium dog

7-11.5 years



Large dog

7-10.5 years



Giant dog

5-9 years





Problems associated with aging


          We all age and can expect certain physiological changes to accompany the aging process. The effect of aging on the body is observed as a gradual decline in the functional capacity of organs, beginning shortly after the animal has reached maturity. Different systems of the body age at different rates, and the degree of compromised function that must occur before clinical signs are seen depends on many factors in the pet’s life.


          The aging process obviously affects every body system, but we will discuss some of the most common health conditions your friend may need help with as he/she enters the golden years.



Metabolic effects of aging


          In dogs (and some cats), the resting metabolic rate (RMR) slows as the animal ages. Changes in body composition include:


          A decrease in the total body water (dehydration may be a concern in the older pet; this is a real concern in cats as their thirst drive diminishes with age). Please note that senior pets are at higher risk for dehydration due to possible osmoregulatory disturbances, renal insufficiency/failure and medications such as diuretics.


          A decrease in the percentage of lean body tissue (muscle – many older pets like people, look “gaunt” in the face). It is important not to deprive our older pets of protein calories unless necessary (i.e. advanced kidney disease). Although, a number of factors are implicated in the loss of muscle mass, alterations in whole-body protein turnover are ultimately responsible for this loss (protein degradation and protein synthesis, especially in skeletal muscle, are lower in elderly individuals).


          An increase in the percentage of body fat. Most pets, especially dogs, “slow down” voluntarily (reduce their physical activity) as they become older. Total daily energy requirements may decrease by as much as 30-40% during the last one third of a pet’s life span as a result of decreased metabolic rate and physical activity. In many mid-age to older pets it is necessary to initiate a weight loss program for these reasons. Overweight senior pets are at risk for a number of problems including diabetes mellitus, osteoarthritis, respiratory and cardiovascular compromise.


          Although weight gain (and obesity) appears to be a common problem in mid-age, the prevalence of an underweight body condition begins to rise in the golden years (especially cats). In this case scenario, an energy dense diet may be necessary. Weight loss in the senior pet may be due to a number of factors including metabolic diseases, maldigestion, partial inappetance (due to lack of saliva, periodontal disease, and senility), cancer, etc.



Musculoskeletal system




          As animals age, they lose muscle and bone mass and experience degeneration of cartilage. Arthritis is the single most common problem of the musculoskeletal system. Osteoarthritis is a syndrome affecting synovial joints that is characterized by chondrocyte death (with fewer chondrocytes, there is decreased production of glycosaminoglycans [GAGs], type 1 collagen and chondroitin sulphate), deterioration of articular cartilage and periarticular tissue change. Synovial fluid is altered; thickening of the joint capsule and osteophyte formation are common. Unfortunately, animals with arthritis suffer pain and decreased mobility. Pain affects not only the animal’s willingness to move but can affect its disposition as well. Pain control can have a tremendous effect on improving mobility, disposition and client/pet enjoyment. Thankfully, there are a number of treatment options now available for the pet with arthritis.



What can I do to help my older pet with osteoarthritis?


1. Recognize the signs. Usually more obvious in the dog but may not be in the cat. Twenty signs a cat may be in pain (according to the October 2007 issue of Trends Magazine) include change in normal behaviour, vocalization, lack of jumping, change in facial expression, isolation, limping/change in gait, inappropriate urination, avoiding stairs, constipation, weight loss, decreased appetite, grouchiness, sudden aggression, changes in posture, retraction from touch, sudden aging, lack of grooming, trying to escape, over-grooming and thrashing.


2. Keep the weight off.


3. Provide nutraceutical support for cartilage: Most commonly glucosamine (a precursor glycosaminoglycans [GAG] and chondroitin sulphate (a GAG found within the extra cellular matrix of articular cartilage). Also, Omega 3 fatty acids with their anti-inflammatory effect, and minerals such as manganese, zinc and copper. Many of these nutraceuticals are added to senior diets (such as Medi Cal/Royal Canin® Mobility and Hills Prescription Diets® J/D) which have been shown to relieve the stiffness and discomfort associated with arthritic degeneration.


4. Moderate and safe exercise. Environmental enrichment: physiotherapy, easy access to the right size litter box, easy access to food and water bowls, use of ramps, padded bedding, assisted grooming etc.


5. Multimodal analgesic regimen. Analgesics such as NSAIDS (nonsteroidal anti-inflammatories), on their own or in combination with other agents. Some commonly used drugs are Meloxicam, Tramadol and Gabapentin.



Organ function


          Liver and kidney function are imperative to a healthy body and therefore the effects of aging on them is something that must be carefully monitored, and when signs of deterioration noted, steps taken to support their function. The liver performs a myriad of functions which include helping in food digestion and utilization, and the elimination of harmful toxins and poisons. The kidney’s also play many roles in metabolism including eliminating toxic substances and helping maintain water balance and a healthy blood pressure.


          Liver and kidney function is monitored by performing blood tests and urinalysis. The results of these tests will tell us when it is time to take action in supporting the impaired function and to try and slow down further deterioration. This help is often given by the addition of supplements and changing the diet being fed. A sample would be the Reduced Protein or K/D diets fed to pets with renal disease, or the supplement SAM – e, used in liver disease.


          Another organ – the largest one – is the skin which by the nature of its function (on the outside and coming into contact with our environment 24 hours a day) is very susceptible to the changes brought on by time.



Skin and hair coat


          As the animal ages, the hair/coat often becomes dull and lustreless, with areas of alopecia and callus formation appearing over pressure points. Hair loss develops as a result of decreased follicular activity. More frequent grooming is necessary. An increase in the number of white hairs on the muzzle is frequently present. Atrophy of melanocytes (cells responsible for pigment production) results in graying of the coat. The footpads of some dogs are hyperkerantinized, and the nails may become malformed and brittle. More frequent nail trims are recommended in the older patient. The skin becomes less pliable.


          Older animals have increased numbers of skin masses e.g. sebaceous gland cysts, adenomas and lipomas. The average age of onset for skin tumours in the dog is 10.5 years, 12 years in cats. Early detection of any tumour may improve longevity for the animal.


          Scheduling regular veterinary examinations is one of the most important steps pet owners can take to keep their pets in tip-top shape. When dogs and cats enter the senior years, these health examinations are more important than ever. Senior care, which starts with the regular veterinary exam, is needed to catch and delay the onset or progress of disease and for the early detection of problems such as organ failure and osteoarthritis. The veterinarian will conduct a complete examination of all your pet’s body systems. Client education and laboratory testing are also key components of the senior exam.



Laboratory testing


          Veterinarians depend on laboratory results to help them understand the status of your pet’s health. When your pet is healthy, laboratory tests provide a means to determine your pet’s “baseline” values. When your pet is sick, the veterinarian can more easily determine whether or not your pet’s lab values are abnormal by comparing the baseline values to the current values. Subtle changes in these laboratory test results, even in the outwardly healthy animal, may signal the presence of an underlying disease. AAHA (American Animal Hospital Association)  recommends that dogs and cats at middle age undergo laboratory tests at least annually. During the senior years, laboratory tests are recommended every 6 months for healthy dogs and cats. At a minimum, the following tests are recommended:


 Complete blood count: This common test measures the number of red blood cells and platelets in a given sample of blood. The numbers and types of these cells give the veterinarian information needed to help diagnose anaemia, infections and leukemia. A complete blood count also helps your veterinarian monitor your pet’s response to some treatments.


Urinalysis: Laboratory analysis of urine is a tool used to detect the presence of one or more specific substances that normally do not appear in urine, such as protein, sugar, white blood cells, or blood. A measurement of the dilution or concentration of urine is also helpful in diagnosing diseases. Urinalysis can assist the veterinarian in the diagnosis of urinary-tract infections, diabetes, dehydration, kidney problems, and many other conditions.


Blood-chemistry panel: Blood-chemistry panels measure electrolytes, enzymes and chemical elements such as calcium and phosphorous. This information helps your veterinarian determine how various organs, such as kidneys, pancreas, and liver, are currently functioning. The results of these tests help your veterinarian formulate an accurate diagnosis, prescribe proper therapy, and monitor the response to treatment. Further testing may be recommended based on the results of these tests.


Parasite evaluation: Microscopic examination of your pet’s feces can provide information about many different kinds of diseases, such as difficulties with digestion, internal bleeding, and disorders of the pancreas. Most importantly, though, this test confirms the presence of intestinal parasites, such as roundworm, hookworm, whipworm, tapeworm and Giardia.


          For cats, an additional routine blood test is recommended in order to check for hyperthyroidism, a common ailment in senior cats. Additionally, depending on your individual pet’s condition and other factors, other tests and assessments might be recommended. These include a heartworm test; a feline leukemia/feline immunodeficiency virus test in cats; blood pressure evaluation; urine protein evaluation; cultures; imaging such as x-rays, ultrasound and echocardiography;  electrocardiography, and special ophthalmic evaluations, among others. Additional tests become especially important in evaluating senior pets that show signs of sickness or are being prepared for anaesthesia and surgery.


          We always recommend annual examinations even when no vaccinations are required. However, after 7 years of age it is wise to bring him/her in more often as our pets are aging more quickly than ourselves and we don’t want to miss the early stage of some aging related illness.

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