Validation of a photogrammetric technique for computing equine hoof volume.

Assessment of equine foot conformation is often based on linear and angular measurements performed on lateral digital photographs. However, quantification of external foot conformation requires more comprehensive assessments to capture the shape of the entire foot. Volumetric measurements of the hoof capsule represent a summary measure quantifying foot shape. The aim of this study was to develop a method for computation of virtual foot models from digital foot images allowing precise and accurate volumetric measurements. This photogrammetric technique was then assessed for the characterization of foot volume changes associated with foot trimming. Using the technique, three different photographers imaged feet from 18 cadavers at different time points and one analyst processed their images to generate virtual computer models. Volumetric measurements were obtained from these models to determine their precision in the context of 'Photographer', 'Time' and the effect of 'Trimming'. Computed tomographic (CT) imaging was used to assess the accuracy of the photogrammetric method. Pre-trim photogrammetric measurements showed excellent precision and accuracy and the results did not depend on the person acquiring the images. The accuracy of post-trim photogrammetric measurements deteriorated in comparison with the average differences measured by CT imaging (19 cm(3)). Precise volumetric measurements were obtained using the photogrammetric method, but average differences in foot volume after trimming as measured by CT imaging are likely too small to be detected with confidence.

Coccidioidomycosis in horses: 15 cases (1975-1984).

Fifteen confirmed cases of equine coccidioidomycosis that originated in California and Arizona were studied retrospectively. Age, breed, and sex varied among affected horses. The most common historical problems were chronic weight loss (53% of cases) and persistent cough (33% of cases). The most frequent physical examination abnormalities were related to the respiratory tract (60% of cases). In 27% of cases, horses had signs of musculoskeletal pain. Horses consistently had hyperproteinemia, hyperfibrinogenemia, leukocytosis, and neutrophilia. An antemortem etiologic diagnosis was made for 11 (73%) horses, all of which had positive serologic tests for coccidioidomycosis. Of the seropositive horses, 5 (46%) also had positive cultures for Coccidioides immitis. One horse died naturally. The other 14 were euthanatized. Prolonged treatment with specific antifungal agents was attempted in 4 horses without apparent benefit. Postmortem abnormalities included pulmonary parenchymal lesions (64% of cases), thoracic lymphadenopathy (57% of cases), hepatic parenchymal involvement (43% of cases), and osteomyelitis (29% of cases). The lesions were granulomatous or pyogranulomatous and C immitis was observed microscopically in 83% of cases.

Midsagittal intraarticular fracture of the third phalanx in a colt.

A 6-month-old Quarter Horse colt, with severe left foreleg lameness of 6 weeks' duration, had swelling of the distal interphalangeal joint and a smaller-than-normal left front foot. Radiographs revealed a nondisplaced, midsagittal, intraarticular fracture of P3, which was treated with an eggbar shoe with 2 quarter clips, and stall rest for 10 weeks. The colt was sound after 10 weeks.

Toxic hepatic failure in newborn foals.

Eight foals, 2 to 5 days of age, with similar clinical signs and laboratory and pathologic findings, died from hepatic failure. The predominant clinical signs were depression and icterus. Abnormally high values were found for plasma ammonia content, aromatic-to-branch-chain amino acid ratio, total serum bilirubin content, gamma glutamyl transferase activity, alkaline phosphatase activity, and PCV; partial thromboplastin time and prothrombin time were prolonged. Some foals had high sorbitol dehydrogenase activity. These laboratory findings were suggestive of subacute hepatic disease and failure. Predominant pathologic findings were limited to the liver and brain. The livers were less than half the expected size for 2- to 5-day-old foals, had prominent bile ductule proliferation, hepatic cell necrosis, and mild periportal fibrosis. These findings suggested both prenatal and postnatal diseases caused by exposure to a hepatoxin. The predominant lesion in the brain was the presence of Alzheimer type II astrocytes, which are characteristic of hepatoencephalopathy. Although the periportal fibrosis was suggestive of in utero exposure to a toxin, epidemiologic information suggested that the hepatic failure more likely resulted from oral inoculation of a microorganism culture product at birth. The same disease was reproduced in 2 newborn foals by feeding this product.