Survey of Ocular Findings in Cattle Immediately Post Slaughter in Two UK Abattoirs

To describe ocular lesions found in cattle immediately post slaughter in two UK abattoirs.

Three hundred fifty-six cattle were examined in two UK abattoirs.

Prospective, descriptive, and observational study design. All bovine eyes received an ophthalmic examination by a single examiner (RG) immediately post slaughter, which included slit lamp examination, indirect ophthalmoscopy, and photography. The eyes were examined within the head after it had been skinned. Histopathology was performed in a selection of cases where required to further characterize the ocular lesions identified.

Over two-thirds (73%, 261/356) of the cattle were female. The median age of cattle at slaughter was 30 months (range: 14-223). One hundred three cattle (29%) had a total of 190 ocular lesions with 142 eyes affected. Cataract in 79 eyes and corneal pathology in 50 eyes were identified. Corneal lesions were classified as active (18 eyes) and inactive (32 eyes). Other ocular pathology identified in eyes included fundic lesions (16), anterior lens capsule pigment (15), a hyperpigmented iris (8) and anterior synechiae (7). Independent of the ocular pathology, 96% (490/510) of eyes examined during nine of the abattoir visits had perilimbal mid-stromal linear corneal opacities. Eight corneal samples were submitted for histopathology and these linear stromal opacities correlated to a combined perilimbal stromal ingrowth of blood vessels and nerve fibers.

Ocular lesions, including active corneal lesions, were frequently observed immediately post slaughter, which is a welfare and economic concern. Perilimbal neovascularization combined with nerve fiber proliferation was a common clinical and histopathological finding.