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At least 19 recordsLinked to original sources
PubMed2001

Metabolic hoof horn disease. Claw horn disruption.

Low-quality hoof horn is a frequent underlying cause of lameness in cattle. Because the lesions that are observed are the result of insults that affect horn production at the cellular level, the term claw horn disruption has been proposed to describe the disease process. Although claw horn disruption may result from multiple etiologies, the response of the keratinocytes is relatively nonspecific in that lesions often appear the same regardless of cause. To solve herd problems, the investigation of possible etiologies must be integrated with a basic understanding of the anatomic and physiologic features of hoof horn production.

Acidosis↗
PubMed2003

Basement membrane integrity and keratinization in healthy and ulcerated bovine hoof tissue.

Damage to, or deterioration of, the keratinized horn tissue of the bovine hoof claw culminates ultimately in the development of solear ulceration. We have observed abnormal keratin distribution at the site of solear ulceration in the bovine claw that may be due to alteration of the positional cues of the keratinocytes. In this study we have characterized key cell biological changes associated with ulceration in the claw that may precipitate abnormal keratinization. Loss of basement membrane at sites of ulceration was found by immunofluorescent detection of laminin and integrins. In other tissues, basement membrane breakdown results from degradation by matrix metalloproteinases (MMPs). Similarly, elevated levels of MMPs 2 and 9 were observed in ulcerated bovine claw tissue both by zymography and, quantitatively, by assay of enzyme activity. In the sole of claws that contained an ulcer, tissue distal to the ulcer site also had elevated MMP 2 when compared with healthy sole tissue from the same animals, as did sole tissue of claws recovering from ulceration. Tissue inhibitor of metalloproteinase 2 (TIMP 2) was detected by ELISA in healthy tissue. TIMP 2 tended to be lower in diseased tissue distal to ulcer sites, and was significantly lower in ulcerated tissue. MMP 2 was located by immunofluorescence in the dermal and basal epidermal region of sole tissue, in the region of the basement membrane. Increased punctate staining of material in the dermis was associated with ulcerated material. ELISA of TIMP 2 in tissue extracts enriched for dermis or epidermis confirmed that the inhibitor was located predominantly in the dermis. To investigate a possible causal relationship between basement membrane anchorage and epidermal keratinization, the effect of function-blocking antibodies to laminins and integrins was tested in tissue explant cultures prepared from healthy sole tissue. Anti-integrin antibody treatment had no effect on either protein or DNA synthesis. In contrast, in the presence of anti-laminin antibody, protein synthesis was decreased in a concentration-dependent manner, a significant effect being observed at the highest concentration after treatment for 24 h. At this concentration, DNA synthesis was also decreased after 48 h of culture, an effect that may be relevant to a hibernal reduction in claw cell turnover, and the associated seasonal vulnerability of cows to claw damage. The results provide evidence for basement membrane disruption at ulcer sites, and an increased potential for disruption in the diseased claw, and a causal link between this and abnormal epidermal keratinization. Basement membrane disruption is in turn associated with reciprocal changes in MMPs and their inhibitors, favouring extracellular proteolysis. Whether MMP activation is the primary cause of dermal-epidermal deterioration and, if so, how MMP activation is triggered, remains to be determined.

Animals↗
PubMed1990

The use of isoelectric focusing to identify rhinoceros keratins.

Keratins represent the principal structural proteins of hair. They are also found in horn, nail, claw, hoof, and feather. Hair and nail samples from human and canine sources and hair samples from mule deer, white tail deer, cat, moose, elk, antelope, caribou, raccoon, and goat were studied. Parrot and goose feathers were also analyzed. Keratins are polymorphic, and species differences are known to exist. Proteinaceous extracts of deer and antelope antlers and bovine and rhinoceros horn were prepared by solubilizing 10 mg of horn sample in 200 microL of a solution containing 12M urea, 74mM Trizma base, and 78mM dithiothreitol (DTT). Extraction took place over a 48-h period. A 25-microL aliquot of extract was removed and incubated with 5 microL of 0.1 M DTT for 10 min at 25 degrees C. Keratins were then separated by isoelectric focusing (IEF) on 5.2% polyacrylamide gels for 3 h and visualized using silver staining. At least 20 bands could be observed for each species studied. However, band patterns differed in the position of each band, in the number of bands, and in band coloration resulting from the silver staining process. Horn from two species of rhinoceros was examined. For both specimens, most bands occurred in the pH range of 4 to 5. Although similar patterns for both species were observed, they differed sufficiently to differentiate one from the other. As might be expected, the closer two species are related phylogenetically, the greater the similarity in the IEF pattern produced from their solubilized keratin.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1985

Incorporation of L-75Se-cystine in tissue fragments from the matrix of the hoof and the claw--a tool for studying the pathogenesis of laminitis?

An in vitro method has been designed and used to study the incorporation of 75Se-cystine into matrix fragments from hooves and claws of healthy horses and cattle. Tissue fragments from the zone of keratinisation were incubated with L-75Se-cystine in a tissue culture medium for 4 to 6 h, during which time there was continuous incorporation of the labelled selenocystine. The incorporation was greatly decreased by adding L-cystine to the incubation mixture. It is concluded that the incorporation of 75Se-cystine depends on the presence of a specific receptor for cystine in the tissue fragments studied. The possible application of the method to studies of the pathogenesis of laminitis is discussed.

Animals↗
PubMed2002

The effect of claw trimming on the hoof health of Swedish dairy cattle.

A 2-year experiment on the effect of claw trimming on hoof health was performed in 77 Swedish dairy herds (3444 dairy cattle) selected on herd size, breed composition and membership in the official milk-recording scheme. In the autumn, cows within each herd were blocked according to breed, parity and stage of lactation and allocated to two treatments: autumn trimming (AT) or no autumn trimming (NAT). Outcome variables were claw measurements and prevalence of hoof lesions and lameness (measured at spring trimming) and the need for hoof treatments between scheduled trimmings. At spring trimming, NAT cows had longer and shallower claws than AT cows. The average net growth of the toe wall was greater for AT than for NAT cattle, with a marked variation between housing systems. Most hoof lesions present at AT had disappeared at the subsequent spring trimming. Controlled for clustering by herd-within-year and for the effects of individual-and herd-level covariates, AT cattle at spring trimmings had significantly lower odds of lameness (OR=0.66) and of haemorrhages of the sole or white-line (OR=0.86), sole ulcer (OR=0.59) and white-line fissure or double sole (OR=0.71)-but not of moderate-to-severe heel-horn erosion or dermatitis (OR=0.96). Acute hoof treatments between claw trimmings were more common in the NAT group (OR=2.02).

Animal Husbandry↗
PubMedDate not supplied

Development and evolution of the mammalian limb: adaptive diversification of nails, hooves, and claws.

Paleontological evidence indicates that the evolutionary diversification of mammals early in the Cenozoic era was characterized by an adaptive radiation of distal limb structures. Likewise, neontological data show that morphological variation in distal limb integumentary appendages (e.g., nails, hooves, and claws) can be observed not only among distantly related mammalian taxa but also among closely related species within the same clade. Comparative analysis of nail, claw, and hoof morphogenesis reveals relatively subtle differences in mesenchymal and epithelial patterning underlying these adult differences in distal limb appendage morphology. Furthermore, studies of regulatory gene expression during vertebrate claw development demonstrate that many of the signaling molecules involved in patterning ectodermal derivatives such as teeth, hair, and feathers are also involved in organizing mammalian distal limb appendages. For example, Bmp4 signaling plays an important role during the recruitment of mesenchymal cells into the condensations forming the terminal phalanges, whereas Msx2 affects the length of nails and claws by suppressing proliferation of germinal epidermal cells. Evolutionary changes in the form of distal integumentary appendages may therefore result from changes in gene expression during formation of mesenchymal condensations (Bmp4, posterior Hox genes), induction of the claw fold and germinal matrix (shh), and/or proliferation of epidermal cells in the claw matrix (Msx1, Msx2). The prevalence of convergences and parallelisms in nail and claw structure among mammals underscores the existence of multiple morphogenetic pathways for evolutionary change in distal limb appendages.

Animals↗
PubMed1981

Incidence of foot disorders in cattle.

A clinical survey of foot lameness in cattle indicated incidence of 9.2% (432/4695), with 365 cases (84.5%) occurring in hot humid zones having high rainfall. Of the 432 affected animals, 399 (92.4%) were females; most were Jerseys and Friesians 3-7 years old. Scissor claw (32.6%), overgrown hoof (27.2%) and corkscrew claw (18.2%) were the most common foot abnormalities. Other less frequently observed conditions included beak claw, bruising of sole, interdigital growth, claw hypoplasia and arthritis. More forefeet (238) than hindfeet (104) were affected.

Age Factors↗
PubMed1996

Prevalence of lesions associated with subclinical laminitis in first-lactation cows from herds with high milk production.

OBJECTIVE: To determine prevalence of lesions associated with subclinical laminitis in first-lactation Holstein cows during early lactation and pregnant Holstein heifers during late gestation in herds with high milk production. DESIGN: Cross-sectional study. ANIMALS: 203 cattle in 13 herbs. PROCEDURE: Cattle were placed in lateral recumbency to allow visual examination and photography of their hooves. Claws on a forelimb and hind limb were examined on all cattle. Observable categories of lesions considered to be associated with subclinical laminitis in our study included yellow waxy discoloration of the sole, hemorrhage of the sole, separation of the white line, and erosion of the heel. RESULTS: Lesions in at least 1 of the categories were found in all herds. Lesions in all categories were found in 11 of 13 herds. Among claws, hemorrhage of the sole was observed most frequently in the lateral claw of the hoof of the hind limb. When days in milk was treated as a covariate, significant (P < 0.01) differences were detected in the prevalence of lesions between herds. CLINICAL IMPLICATIONS: Because the prevalence of lesions differed significantly among herds, it is logical to believe that causative factors and corrective measures also may have differed among herds.

Animal Feed↗
PubMedDate not supplied

The hardness of horn in different segments of the bovine claw.

Hardness of bovine hoof horn was tested as ball indentation hardness and as shore D hardness post mortem in different segments of the hoof wall, in the sole and the hard bulb of sound claws of 10 Austrian Holstein Friesian cows. Both methods of hardness determination showed corresponding results, with shore D hardness between 52.2 and 63.9 hardness units (hu) and ball indentation hardness between 11.2 N/mm2 and 24.3 N/mm2. Bovine hoof horn becomes significantly softer from the coronary band towards the weight bearing border (vertical decrease) and from the dorsal wall towards the heel (horizontal decrease). Decreasing hardness was associated with decreasing dry matter content. Measurements of the claw capsule showed thickness of the hoof wall increasing from the coronary border towards the sole. In dorsopalmar/-plantar direction, bovine hoof wall at the weight bearing border decreases towards the heel.

Animals↗
PubMed1998

Effect of differential delivery of isoflurane to head and torso on lumbar dorsal horn activity.

BACKGROUND: The spinal cord appears to be the site where anesthetic agents prevent movement in response to noxious stimuli. When isoflurane is differentially delivered to the head and torso (with low torso concentrations), cranial anesthetic requirements increase compared with systemic administration. The aim of the current study was to test the hypothesis that isoflurane action in the brain has descending influences on spinal cord dorsal horn neurons. A secondary aim was to determine the association, if any, of high cranial concentrations of isoflurane (>6%) with dorsal horn activity. METHODS: Ten goats were anesthetized with isoflurane and the carotid arteries and jugular veins isolated and cannulated for cerebral bypass. A laminectomy was performed for recording from single lumbar dorsal horn neurons with hind limb mechanical receptive fields (one cell per goat). A standard noxious mechanical stimulus was applied to the dew claw or hoof bulb during a control period with end-tidal isoflurane at 1.3% and during bypass with the following head/torso isoflurane concentrations: 1.3%/1.3%, 3.2%/1.3%, 9.4%/1.3%, 1.3%/0.2%, 3.0%/0.2% and 8.8%/0.3%. RESULTS: When torso isoflurane concentration was 1.3%, increasing cranial isoflurane concentration to 3% or 9% had no significant effect on the activity of dorsal horn units. When torso isoflurane was 0.2-0.3%, spontaneous activity increased; however, at these torso concentrations, evoked responses were significantly decreased (-60%) only when cranial isoflurane concentration was increased to 9%. CONCLUSIONS: Isoflurane action in the brain had an inhibitory effect on dorsal horn activity with the combination of supraclinical cranial and low torso concentrations.

Anesthetics, Inhalation↗