Macroscopic, Radiographic and Histopathologic Changes of Claws with Laminitis and Laminitis-Related Disorders in Zero-Grazed Dairy Cows

Abstract

Laminitis and laminitis-related claw disorders are prevalent in zero-grazed dairy cows. Confinement and limited movement influences claw size and shape. Abnormal claw size and shape causes imbalanced body weight distribution on the claws. Claw horn growth and wear is impaired, further aggravating laminitis disorders. The objective of this study was to determine: macroscopic disorders on the claws, as well as radiographic features and histopathologic changes on the claws with laminitis/laminitis-related disorders. A total of 159 dairy cow forelimb and hind limb feet (318 claws) were collected from an abattoir and a slaughter slab around Nairobi, Kenya. The claws were examined for mac roscopic abnormalities, dorso-palmar or dorso-plantar radiography done, sagittal claw sections done, corium gross changes observed and corium tissues harvested for histopathology. Macroscopic disorders observed were: sole bruising, claw deformities, heel erosion, subclinical laminitis sole haemorrhages, double soles, chronic laminitis and white line separation. Radiographic changes observed mainly on distal phalanges were dilated vascular channels, irregular margins, exostoses/periostitis, distal phalangeal narrowing and lysis. Histopathologic changes in the corium included arterio-venous shunts, vascular wall rupture and thickening, vascular proliferation and thrombosis, corium and connective tissue oedema, degeneration, haemorrhages and spongiosis. Hence macroscopic, radiographic and histopathologic changes in laminitis claws affect locomotion.