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L aminitis is a debilitating and often fatal condition in horses, in which separation of the laminar junction between the hoof wall and dermis occurs. 1 Early detection of laminitis is crucial to initiate appropriate therapy before the occurrence

Open access
in American Journal of Veterinary Research

Various investigators have evaluated the percentage of moisture content of equine hoof walls, with reported values ranging from 16% to 36%. 1,2 , a–c One study c involved use of various methods, including drying with potassium phosphate, freeze

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in American Journal of Veterinary Research

the loads applied to the hooves. 7 , a The hoof wall is relatively hard and insensitive and acts as a barrier to protect the structures within the hoof capsule. The shapes of the hoof capsule and the inner structures affect how forces generated

Full access
in American Journal of Veterinary Research

At birth, the hoof wall is covered and protected by soft horn (perionychium), which is rapidly worn away as a foal moves within its new environment. The hard outer pigmented part of the foot is gradually exposed to provide support for the newborn

Full access
in American Journal of Veterinary Research

Equine hoof mechanics and function have been investigated for many years. One of the most reliable methods with which to assess hoof wall distortion is extensometry, a technique that uses electrical resistance strain gauges to identify changes in

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in American Journal of Veterinary Research

part of the hoof wall from the underlying sensitive tissues when mechanical traction is applied across the lamina. 1 In both horses with naturally occurring and those with experimentally induced laminitis, it is debatable whether any treatment approach

Full access
in American Journal of Veterinary Research

removed from approximately 80% of the joint surface. A 9.5-mm drill bit was used under fluoroscopic guidance to create holes through the dorsal aspect of the hoof wall. A total of 4 holes were created in the dorsal aspect of the hoof wall, but the first

Full access
in Journal of the American Veterinary Medical Association

SUMMARY

In this study, we described water-insoluble proteins extracted from the germinative regions (stratum internum and coronary band epithelium) and the cornified outer surface (stratum medium) of the equine hoof wall. Two major types of polypeptides were identified: the intermediate filaments (if) and the if-associated proteins. The if, including keratins, composed a major portion of this fraction, had electrophoretic mobilities on sodium dodecyl sulfate-polyacrylamide gel electrophoresis in the range of 40 to 80 kDa, and reacted with acidic or basic keratin-specific monoclonal antibodies. Differences in the composition of keratins between germinative layers and the stratum medium were seen. Another less well-characterized group of polypeptides associated with the if also were extracted with the water-insoluble polypeptide fraction. These associated proteins had an apparent molecular weight between 10 and 30 kDa on sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and contained a higher percentage of sulfur-containing amino acids than did the if. Water-insoluble protein fractions compared favorably with those found in other less-specialized keratinizing tissue with respect to size, immunoreactivity with monoclonal antibody, and amino acid composition.

Free access
in American Journal of Veterinary Research

Abstract

Objective—To evaluate the use of hoof wall surface temperature (HWST) as an indirect indicator of digital perfusion and to describe HWST patterns during the prodromal and acute phases of carbohydrate-induced laminitis in horses.

Animals—30 adult horses without foot abnormalities.

Procedures—Three experiments were performed. In the first, HWST was measured in 2 groups of horses acclimatized to hot (n = 6), or cold (6) environments and exposed to cold (15 C) ambient temperature. In the second experiment, HWST were measured in both forefeet of 6 horses before and after application of a tourniquet to 1 forefoot to induce vascular occlusion. In the third experiment, HWST were recorded in 12 horses before and during the prodromal and acute phases of carbohydrate-induced laminitis.

Results—Mean HWST of hot-acclimatized cold-challenged horses was significantly less than that of cold-acclimatized cold-challenged horses at all times. Transient episodes of high HWST were observed during prolonged cold-induced vasoconstriction. Hoof wall surface temperature significantly decreased during arterial occlusion and increased during reperfusion. Digital hypothermia was observed during the prodromal phase of carbohydrate-induced laminitis.

Conclusions and Clinical Relevance—Determination of HWST is a valid technique to evaluate digital perfusion under appropriate controlled conditions in horses. Digital hypothermia detected during the prodromal phase of laminitis is consistent with decreased digital vascular perfusion or metabolic activity. If administered to horses during the prodromal phase, agents that enhance digital perfusion may prevent development of laminitis. (Am J Vet Res 2001; 62:1167–1172)

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in American Journal of Veterinary Research

Abstract

Objective—To localize substance P (SP) and neurokinin A (NKA) and their receptors in the insertion of the distal sesamoidean impar ligament (DSIL), deep digital flexor tendon (DDFT), and dorsal hoof wall of healthy feet of horses.

Sample Population—18 healthy feet from horses.

Procedure—Samples from the dorsal hoof wall and insertion of the DSIL and DDFT of 10 feet were processed for immunocytochemical analysis, using rabbit polyclonal antisera raised against SP and NKA. Tissue sections from 8 feet were incubated with I125-labeled SP to localize tachykinin receptors and their specificity and with control solutions of radioactive SP and excess nonradioactive SP to identify areas of nonspecific binding.

Results—Many nerves immunoreactive for SP and NKA were localized to the region of the insertion of the DSIL and DDFT and the accompanying microvasculature and arteriovenous complexes (AVC) as well as to the microvasculature of the dorsal hoof wall. Specific neurokinin 1 receptors were localized over the microvessels and AVC of the insertion zone and small microvessels of the hoof wall.

Conclusions and Clinical Relevance—These results document that the microvasculature of the equine foot is richly innervated and has specific receptors for tachykinins. Distributions of these tachykinin receptors on the microvasculature suggest that they form an important vasodilatory mechanism for controlling blood flow through the DSIL-DDFT insertion and dorsal hoof wall. (Am J Vet Res 2002;63:222–228)

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in American Journal of Veterinary Research