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    A history of lameness is associated with reduced proportions of collagen type I relative to type III in the digital cushions of dairy cattle
    (Elsevier B.V., 2025-12) Wilson JP; Green MJ; Randall LV; Huxley JN; Alibhai A; Ferguson HJ; Rutland CS
    Hoof horn lesions (HHL) are a highly prevalent and recurrent causes of lameness in dairy cattle globally. The digital cushion is composed of 3 cylinders of adipose tissue embedded in a system of collagenous connective tissue, which are designed to reduce the risk of HHL onset. Previous research has identified that animals with a history of lameness and HHL are more likely to have a reduced digital cushion volume in their lateral digits, but the impact on the histological structure remains unknown. Collagen is an important fibril related to adipose tissue structure and function, but its role in the digital cushion is poorly understood. Our study aimed to examine the proportions of type I and type III collagen within the digital cushions of dairy cattle at cull, and to investigate associations with digital cushion volume, lameness, and HHL occurrence throughout the animal's life. This retrospective cohort study resulted in 599 digital cushions being dissected from the hind feet of 54 animals. Digital cushion tissue underwent picrosirius red staining, combined with systematic random sampling and collagen content analysis. The results described the relative proportions of type I and type III collagen. The proportion of type I collagen was used as the outcome variable in multivariable linear regression models. The median (minimum–maximum) proportion of collagen that was type I contained within the lateral and medial digits was 56.2% (23.6%–83.8%) and 59.6% (13.3%–92.7%) respectively. The proportion of type I collagen was lower in animals that had a history of HHL and lameness throughout their lives. Animals with a lower BCS at cull or that were culled at a later parity had less type I collagen in their lateral digits at cull. Animals with a higher digital cushion volume also had an increased proportion of type I collagen in their lateral digits at cull. Our results have highlighted the histological impact that HHL have on the structure of the digital cushion. We hypothesized that localized inflammation associated with HHL was associated with a remodeling of the adipose tissue within the digital cushion, which would predispose the individual to a future of lameness and HHL.
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    Morphology, adipocyte size, and fatty acid analysis of dairy cattle digital cushions, and the effect of body condition score and age
    (Elsevier Inc and Fass Inc on behalf of the American Dairy Science Association, 2021-05) Newsome RF; Mostyn A; Wilson JP; Alibhai A; Bollard N; Randall L; Chagunda MGG; Sturrock CJ; Keane M; Green M; Huxley JN; Rutland CS
    The digital cushion is an essential part of maintaining a healthy foot, working to dissipate foot strike and body weight forces and lameness from claw horn disruption lesions. Despite the importance of the digital cushion, little is known about the basic anatomy, adipocyte morphology, and fatty acid composition in relation to age, limb position, and body condition score. In total, 60 claws (from 17 cows) were selected and collected from a herd, ensuring that body condition score data and computed micro-tomography were known for each animal. Digital cushion tissue underwent histological staining combined with stereology, systematic random sampling, and cell morphology analysis, in addition to lipid extraction followed by fatty acid analysis. The results describe digital cushion architecture and adipocyte sizes. Adipocyte size was similar across all 4 claws (distal left lateral and medial and distal right lateral and medial) and across the ages (aged 2–7 yr); however, animals with body condition score of 3.00 or more at slaughter had a significantly increased cell size in comparison to those with a score of less than 2.50. Of 37 fatty acid methyl esters identified, 5 differed between either the body condition score or different age groups. C10:0 capric acid, C14:0 myristic acid, C15:0 pentadecanoic acid, and C20:0 arachidic acid percentages were all lesser in lower body condition score cows, whereas C22:1n-9 erucic acid measurements were lesser in younger cows. Saturated fatty acid, monounsaturated fatty acid, and polyunsaturated fatty acid percentages were not altered in the different claws, ages, or body condition score groups. Triglyceride quantities did not differ for claw position or age but had decreased quantities in lower body condition score animals. Digital cushion anatomy, cellular morphology, and fatty acid composition have been described in general and also in animals with differing ages, body condition scores, and in the differing claws. Understanding fat deposition, mobilization, and composition are essential in not only understanding the roles that the digital cushion plays but also in preventing disorders and maintaining cattle health and welfare.