Practice Scenario

Meet Dewey, a senior cat that has lost weight.

Get to know DEWEY

A 13-year-old, neutered male cat

  • Dewey is an indoor cat presented for gradual weight loss.
  • Owner has not noticed a change in Dewey’s appetite. However, she has 3 cats and group feeds them an adult dry cat food ad libitum plus a “small amount” of canned food occasionally as a treat. She is not sure if Dewey is drinking or urinating more.
  • Dewey has a body condition score of 3/9, weighs 4.3 kg (9.5 pounds), and has moderate muscle loss. Dewey has not been examined in over 2 years. His last recorded body condition score was 5/9 when he weighed 5.4 kg (almost 12 pounds).
  • On exam, Dewey is quiet, but responsive. Mucous membranes are somewhat dry with a normal capillary refill time. Although he is purring, heart and lung sounds appear normal. He exhibits no pain on abdominal palpation. His kidneys feel slightly small.

Abnormal Body Condition

Sarcopenia in Dogs and Cats

Sarcopenia is the age-related loss of lean body mass (LBM) that occurs unrelated to disease. With age, the rate of protein catabolism often exceeds protein synthesis. This imbalance leads to progressive loss of lean body mass with loss of strength, diminished quality of life, and shorter life span.1  Although this condition occurs in both dogs and cats, it seems to be more clinically significant in cats. 

There is no single known cause of sarcopenia. The multifactorial etiology of this slowly progressive condition includes inadequate intake of protein or calories, altered protein turnover with decreased protein synthesis and increased protein catabolism, chronic increase in inflammatory cytokines, mitochondrial dysfunction, and increased oxidative stress.1,2  

While nutrition cannot prevent sarcopenia, the earlier this condition is identified the more opportunity there is to help delay age-related changes in body weight and body composition of older pets. 

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Key Messages

  • Routine nutritional assessments that include body weight, body condition, and muscle condition scoring, can aid in earlier identification of LBM loss. 
    • Tracking only body weight may miss losses of lean body mass that may be masked by increased body fat.2,3  
       
  • Ensure dietary protein is adequate to minimize LBM loss, and only restrict protein if medically essential. 
    • Older dogs and cats have higher protein needs than younger animals.4-6 
    • Inadequate protein intake increases the rate of loss of LBM in aging dogs, while abundant protein slows the loss.7  
    • Guidelines suggest about 2.55 gram of protein/kg body weight for healthy adult dogs and about 5 grams/kg body weight in healthy adult cats while also assuring adequate calorie intake.8  
    • Specific amino acids may play a role in reducing loss of LBM. 
      • For example, one study showed that increasing dietary lysine, independent of total protein, helped reduce loss of LBM in aging cats.9 
         
  • Ensure calorie intake is adequate, keeping in mind that older dogs often need fewer calories while older cats may need more calories to meet their nutritional needs.8 
    • Calorie density varies widely among pet foods—from more than 600 kcal/cup to  less than 250 kcal/cup. Ensure that any weight loss is not the unintended result of switching to a lower calorie food.3 
    • Changes in appetite and/or decreased food intake are common in senior pets. 
      • Strategies to keep senior pets eating include feeding meals more frequently or using flavor enhancers. 
        • Avoid flavor additives that are high in sodium for pets with heart failure, or high in phosphorus for pets with kidney disease.1 
           
  • Fish oil supplementation, high in the long-chain omega-3 fatty acids EPA and DHA, can decrease inflammatory cytokine production and improve food intake.10 
    • Flax seed oil or other plant-based omega-3 fatty acids are ineffective sources of EPA and DHA for these species.11 
did you know

Preserving LBM in aging cats enhances longevity:  A longitudinal study of aging showed that non-obese cats had a 2% increased chance of survival for every 10-gram increase in LBM. 12 

Related Tools and Content:

Lean Body Mass & Protein

Discover the importance of Lean Body Mass (LBM) in overall health for dogs and cats, and the role a high-protein diet can play in slowing LBM loss.

View Research 11 min to 15 min

Protein and Senior Pets

Protein is a key nutrient for dogs and cats and a source of amino acids, the 'building blocks' used to build new proteins in the body. Irrespective of the pet’s age, protein plays many important roles in the body.

View Hot Topic 6 min to 10 min

Taking a Good Diet History

The only way to know what each patient really eats is to ask ꟷ and document the information in the medical record.

View Brief 1 min to 5 min

The Purina Body Condition System

The Purina Body Condition System is an easy and practical tool for assessing a pet's body composition.​

View Brief 1 min to 5 min

Use Muscle Condition Scoring to Detect Muscle Loss in Patients

Muscle condition scoring is a hands-on method for evaluating lean body mass that can be used as part of nutritional assessments.

View Brief 1 min to 5 min

WSAVA Feline Muscle Condition Score Chart

A simple visual guide to help assess muscle mass in cats.

View Chart 1 min to 5 min

WSAVA Canine Muscle Condition Score Chart

A simple visual guide to help assess muscle mass in dogs.

View Chart 1 min to 5 min

To Share With Pet Owner:

Evaluating Your Cat’s Body Condition

Assess your cat's Body Condition in just 3 simple steps.​

View Video 1 min to 5 min

Evaluating Your Dog’s Body Condition

Assess your dog's Body Condition in just 3 simple steps.​

View Video 1 min to 5 min

References

  1. Freeman, L. M. (2012). Cachexia and sarcopenia: Emerging syndromes of importance in dogs and cats. Journal of Veterinary Internal Medicine, 26, 3–17. 
  2. Laflamme, D. P. (2020). Understanding the nutritional needs of healthy cats and those with diet-sensitive conditions. Veterinary Clinics of North America: Small Animal Practice, 50(5), 905–924. doi: 10.1016/j.cvsm.2020.05.001 
  3. Hutchinson, D., Freeman, L. M., Schreiner, K. E., & Terkla, D. G. (2011). Survey of opinions about nutritional requirements of senior dogs and analysis of nutrient profiles of commercially available diets for senior dogs. International Journal of Applied Research in Veterinary Medicine, 9(1), 68–79.  
  4. Laflamme, D. P., & Hannah, S. S. (2013). Discrepancy between use of lean body mass or nitrogen balance to determine protein requirements for adult cats. Journal of Feline Medicine and Surgery, 15(8), 691–697. 
  5. Perez-Camargo, G., Patil, A. R., & Cupp, C. J. (2004). Body composition changes in aging cats. Compendium on Continuing Education for the Practicing Veterinarian, 26(Suppl 2A), 71.  
  6. Wannemacher, R. W., &  McCoy, J. R. (1966). Determination of optimal dietary protein requirements of young and old dogs. Journal of Nutrition, 88(1), 66–74. 
  7. Kealy, R. D. (1999). Factors influencing lean body mass in aging dogs. Compendium on Continuing Education for the Practicing Veterinarian, 2(11K), 34–37.  
  8. Churchill, J. A., & Eirmann, L. (2021). Senior pet nutrition and management. Veterinary Clinics of North America: Small Animal Practice, 51(3), 635–651. doi: 10.1016/j.cvsm.2021.01.004 
  9. Frantz, N. Z., Yamka, R. M., & Friesen, K. G. (2007). The effect of diet and lysine: calorie ratio on body composition and kidney health in geriatric cats. International Journal of Applied Research in Veterinary Medicine, 5(1), 25–36. 
  10. Freeman, L. M., Rush, J. E., Kehayias, J. J., Ross, J. N., Jr, Meydani, S. N., Brown, D. J., Dolnikowski, G. G., Marmor, B. N., White, M. E., Dinarello, C. A., & Roubenoff, R. (1998). Nutritional alterations and the effect of fish oil supplementation in dogs with heart failure. Journal of Veterinary Internal Medicine, 12(6), 440–448. doi: 10.1111/j.1939-1676.1998.tb02148.x 
  11. Bauer, J. E. (2007). Responses of dogs to dietary omega-3 fatty acids. Journal of the American Veterinary Medical Association, 231(11), 1657–1661. doi: 10.2460/javma.231.11.1657 
  12. Cupp, C. J., Kerr, W. W., Jean-Philippe, C., Patil, A. R., & Perez-Camargo, G. (2008). The role of nutritional interventions in the longevity and maintenance of long-term health in aging cats. International Journal of Applied Research in Veterinary Medicine, 6(2), 69–81.