Biomechanics and histology of bovine claw suspensory tissue in early acute laminitis.

摘要: Abstract Weakening of the suspensory tissue supporting pedal bone is central issue in theory acute bovine laminitis, but this aspect has never been tested. The objective study was to investigate effect laminitis on tissue. hypothesis that clinical and histological signs are associated with decreased strength claw. Nonpregnant dairy heifers (n=10) received oral oligofructose overload (17 g/kg body weight) were killed 24 (n=4) 72h (n=6) after overload. Control tap water at 72 or 96h. Clinical, orthopedic, examinations carried out confirm occurrence laminitis. After euthanasia, 2 adjacent samples including horn wall, lamellar layer, dermis, cut from dorso-abaxial each Tissue kept ice until mounted a mechanical testing frame, fixed by bone, loaded failure. A stress displacement curve generated measurements physiological support (force needed displace 1mm beyond first resistance) maximal break tissue) recorded. Heifers treated developed consistent ruminal systemic acidosis treatment as well characterized weight shifting (35% observations vs. 6% controls), moderate lameness (100 17%, score 3 5 72h), reaction hoof (30 50% 48 72h, respectively, 0% controls). Histological examination claws showed changes stretched lamellae, wider basal cells low chromatin density, thick, wavy, blurry appearance basement membrane. Biomechanical results no overload; contrast, increased Herd origin location sample had large effects both (herd=547 N/cm ; location=531 ) claw (herd=260 location=327 ). Despite weakening detected factors appeared be important for strength.