Which clinical signs would support a diagnosis of cerebellar disease in cattle?

The clinical signs that would support a diagnosis of cerebellar disease in cattle are tremors and hypermetria with normal mentation. Cerebellar disease specifically affects the coordination and motor control functions of the animal, which the cerebellum regulates.

Tremors are a common manifestation in conditions that affect the cerebellum, arising from the loss of fine motor control and balance. Hypermetria, or overreaching during movement, is also associated with cerebellar dysfunction as the animal struggles to coordinate its limb movements effectively.

Normal mentation indicates that while the cow is having difficulties with motor control, its cognitive function remains intact. This separation of motor impairment from cognitive impairment is a hallmark of cerebellar disease, which can help differentiate it from other neurological conditions that may also present with ataxia but involve involvement of other brain regions that could affect mentation.

The other signs mentioned in the other choices pertain to different neurological issues or conditions. Therefore, option C accurately captures the key clinical signs typical for diagnosing cerebellar disease.