A dog's weakness in limbs and inability to stand up may be caused by a variety of reasons, including the following:

< p>Nutritional problems: For example, malnutrition, calcium deficiency, etc. will affect the normal function of bones and muscles.

Bone and joint problems: such as fractures, arthritis, bone diseases, etc.

Nervous system problems: Nerve damage, disease, or poisoning may cause weakness in the limbs.

Endocrine disorders: such as hypothyroidism.

Infectious diseases: Bacterial, viral or parasitic infections may affect body functions.

Cardiovascular problems: Heart disease or poor circulation.

Poisoning: Accidental ingestion of toxic substances.

Metabolic diseases: such as diabetes.

Muscle disease: Muscle injury or disease.

Excessive fatigue: prolonged activity or fatigue.