Spruce is helpful for many conditions - and is excellent for sudden fatigue and exhaustion. (animaleo.info)
Symptoms of Heinz body anemia include sudden fatigue and weakness, fever, poor appetite, discolored urine, and pale or discolored skin, gums, and lips. (petconsider.com)
Weak muscles or sudden fatigue in dogs, more technically referred to as Myasthenia gravis, is a syndrome that involves skeletal muscle weakness in the absence of obvious nervous system abnormalities. (petwave.com)