Seeing beyond gait: A case study identifying chronic laminitis in 3 goats

Abstract

Identification of goat lameness on farm is typically recognised as either an overt gait abnormality or non-weight bearing limbs. Subclinical and chronic laminitis in goats tends to present as a mild, uneven gait with abnormally shaped claws; it is possible that animals with these symptoms are experiencing pain, however due to our reliance on overt gait changes, they will not be identified to receive appropriate management, potentially leaving them in a chronic state of suffering. This case study identified the pathological changes associated with laminitis, with a hypothesis that mild lameness does not always correlate with severity of disease process. Three Saanen does, part of a research herd but originally sourced from a commercial milking herd in New Zealand, were suspected to have chronic laminitis. Following photographs, radiographs and infrared thermography, goats were euthanised and claw longitudinal sections were taken; tissue was submitted for histology. Two goats stood and walked normally, and one also stood normally but walked with a slight uneven gait; all goats presented various hoof conformation issues. Radiographs showed distal phalanx remodelling and rotation in all three cases. Post-mortem hoof longitudinal sections and histology presented multiple abnormalities, including but not limited to: irregular cortex of the distal phalanx, distended blood vessels in the dermis and laminae, laminae necrosis, development of abnormal fibrous tissue, and distorted laminae epidermal cells. Histology from two of the goats confirmed the presence of dermal inflammation, and this was seen visually in one goat using infrared thermography. Our case study approach allowed for detailed physical and histological examination of the changes caused by laminitis in ex-commercial dairy goats. This work suggests that chronic laminitis can result in dramatic pathological changes, and that lameness score alone is not a good indication of the severity of these changes. Better interpretation of external abnormalities, such as clubbed and distorted claws, as well as the use of radiographs and infrared thermography, should be more commonly considered for identifying at risk animals in order to initiate appropriate management or end-of-life decisions.