What is the typical clinical sign associated with primary photosensitization in cattle?

Primary photosensitization in cattle typically manifests through clinical signs related to skin sensitivity to sunlight, particularly in areas of unpigmented or sparsely haired skin. The correct choice, squinting, reflects the animal's discomfort when exposed to bright light, which indicates an issue with light sensitivity.

Cattle experiencing primary photosensitization commonly show signs such as squinting and may also exhibit other behaviors like avoiding bright environments. This sensitivity occurs due to the accumulation of photosensitizers, which can lead to damage in the skin and eyes when exposed to sunlight, resulting in inflammation and subsequent discomfort.

Droopy ears, ataxia, and Demodex infections are not characteristic signs of primary photosensitization. Droopy ears could indicate various stressors or systemic issues but are not specific to photosensitization. Ataxia pertains more to neurological conditions rather than skin responses, while Demodex infections are associated with parasites and do not relate to photosensitivity phenomena.