Working Dogs and Exertional Rhabdomyolysis

Dark urine in working breeds after heavy exercise can indicate a condition called exertional rhabdomyolysis, also known as "tying-up" or "Monday morning disease" in working animals. This condition occurs when intense physical activity causes muscle damage, leading to the release of myoglobin (a muscle protein) into the bloodstream. Myoglobin is then filtered by the kidneys and excreted in the urine, giving it a dark or reddish-brown color.

Key Causes and Risk Factors:
1. Muscle Damage: Prolonged or intense exercise can cause muscle breakdown, especially in underconditioned or overworked dogs.
2. Dehydration: Lack of adequate hydration during or after exercise can exacerbate the condition.
3. Electrolyte Imbalances: Low levels of potassium, calcium, or sodium can increase the risk of muscle damage.
4. Underlying Conditions: Genetic predispositions, such as in Greyhounds or sled dogs, may make some breeds more susceptible.
5. Heatstroke: Overexertion in hot conditions can lead to dehydration, muscle damage, and dark urine.
6. Hemolysis: Destruction of red blood cells due to physical trauma (e.g., running on hard surfaces) can also cause dark urine.
7. Kidney Issues: Intense exercise can sometimes strain the kidneys, leading to concentrated or discolored urine.

What to Watch For:
1. Changes in Gait: Look for stiffness or an unusual gait, especially starting in the hind limbs.
2. Muscle Pain or Tenderness: Dogs may flinch or show discomfort when touched, particularly in the back or legs.
3. Shaking or Trembling: Muscle tremors can be an early sign of fatigue or damage.
4. Dark Urine: Reddish-brown urine indicates myoglobin release from damaged muscles.
5. Reduced Performance: Slowing down, reluctance to continue working, or lying down unexpectedly.
6. Humped Back: A hunched posture may signal muscle soreness or cramping.
7. Excessive panting or signs of overheating

How to Prevent It:
1. Gradual Conditioning: Build your dog's endurance and strength gradually. Regular exercise throughout the year prevents sudden overexertion during hunting season.
2. Proper Nutrition: Feed a balanced diet with adequate protein and carbohydrates to support energy needs. Avoid feeding immediately before intense activity.
3. Hydration: Ensure your dog has access to fresh water before, during, and after exercise. Dehydration increases the risk of muscle damage.
4. Electrolyte Balance: Provide electrolyte supplements if needed, especially during hot weather or prolonged activity.
5. Monitor Activity Levels: Avoid pushing your dog beyond its physical limits. Gradually increase the intensity and duration of hunts.
6. Rest and Recovery: Allow your dog to rest between hunts and provide a cool, shaded area for recovery.
7. Year-Round Fitness: Keep your dog active year-round with activities like swimming, hiking, or running to maintain conditioning.

What to Do:
1. Immediate Rest: Stop exercising and allow the dog to rest.
2. Hydration: Provide fresh water to help flush out myoglobin and rehydrate the dog.
3. Veterinary Care: Seek immediate veterinary attention if dark urine persists, as rhabdomyolysis can lead to kidney damage or failure if untreated.

By keeping an eye on these signs and following preventive measures, you can help your hunting dog stay healthy and perform at their best.