• Abnormal swellings that persist or continue to grow
  
• Sores that do not heal
  
• Weight loss
  
• Loss of appetite
  
• Bleeding or discharge from any body opening
  
• Offensive odor
  
• Difficulty eating or swallowing
  
• Hesitation to exercise or loss of stamina
  
• Persistent lameness or stiffness
  
• Difficulty breathing, urinating, or defecating  

*From the American Veterinary Medical Association