Circumocular pigmentation and incidence of ocular squamous cell tumors in Bos taurus and Bos indicus X Bos taurus cattle.

Amount of circumocular pigmentation and incidence of ocular squamous cell tumors were evaluated in dams representing diverse cattle breed types. Each dam was examined twice annually during a specific stage in the life cycle (3.5 to 9.5 years old). Overall, 28.3% of dams in the herd developed at least 1 ocular squamous cell tumor. Breed groups differed (P less than 0.01) in amount of circumocular pigmentation and incidence of tumors. Results indicate that losses from ocular squamous cell tumors in beef herds can be sharply reduced by judicious choice of breed types.