According to AI
Hypercalcemia can have many causes, including:
Cancer
Certain infections
Medications
Ingestion of certain plants
Hyperparathyroidism
Hyperadrenocorticism (Addison's disease)
Bone disease
Fungal infection
Dehydration
Azotemia (accumulation of nitrogenous waste products in the blood)
Also consider this:
https://www.kingsdale.com/a-complete...thirst-in-dogs
Another possibility - dehydration. Total calcium can be falsely increased by diet and dehydration, making it an unreliable test in some situations. Nutritional deficiencies and renal disease are other common causes of hypercalcemia in dogs.
https://wagwalking.com/condition/hypercalcemia
Typical diagnostic labs include: complete blood count, biochemistry panel, ionized calcium test, and urinalysis.
https://www.merckvetmanual.com/endoc...-dogs-and-cats