The lumbosacral spine (L5–S3) was examined by high resolution computed tomography (CT) in five canine cadaver specimens and one anesthetized dog using 5mm thick transverse slices at 5mm intervals. In each dog, anatomic features observed on CT images were confirmed by comparison with corresponding 5 mm thick anatomic transverse sections and section radiographs. CT anatomic features visualized in all dogs included the vertebral bodies, pedicles, laminae, articular processes, spinous processes, transverse processes, mammillary processes, basivertebral venous canals, vertebral foramina, intervertebral foramina, sacral wings, median sacral crest, intermediate sacral crests, lateral sacral crests, articular process joints, sacroiliac joints, internal vertebral venous plexus, epidural fat, thecal sac, L5–S3 nerve roots, and spinal nerves. Spinal ganglia, yellow ligaments, and portions of the intervertebral discs were visible in some dogs. The spinal cord, intrathecal nerve roots, dorsal and ventral longitudinal ligaments, spinal arteries, and radicular vessels were not distinguishable. Accessory processes were identified on the caudal L5 pedicles in most dogs, an observation that differed from descriptions in standard anatomy texts. Previously undescribed osseous grooves, termed “lateral recesses,” were identified in the caudal L7 vertebral foramen of all dogs.

. S, a dominant, lethal, atitosomal gene, was discovered in Auburn University's population of Surotherodon aureus (=Tilapia auera). When present in the heterozygous state (S+). the S gene produces the saddleback phenotype. Saddlebacks are missing part of or all of the dorsal fin. Some fish thai are missing most of or the entire dorsal fin have additional fin disorders and are missing various combinations of the pectoral, pelvic, and anal fins. Each fin disorder is associated with gross skeletal anomalies. Viability in saddlebacks is reduced by 67% during the first three months of life. Those that survive are less resistant to stress and subsequent infection than normal fish. When challenged by Saprolcegnia sp., saddlebacks were far more susceptible to infection (P<0.01). When present in the homozygous state (SS), the gene causes death in fry prior to swim‐up. Thus, a single S gene reduces viability by 67%, and two S genes reduce viability by 100%. The S gene did not affect early growth or dressing percentage. Because it is a dominant gene, the S gene can be eliminated from any population in one generation by culling all saddlebacks.

In a three-year prospective study, computed tomographic (CT) and surgical findings were compared for nine large breed dogs with lumbosacral stenosis. Surgically-excised tissue was examined histologically in seven dogs and additional necropsy evaluation was performed in one dog. The CT ahnormalities observed at sites of confirmed cauda equina compression were: loss of epidural fat, increased soft tissue opacity, bulging of the intervertebral disc margin, spondylosis, thecal sac displacement, narrowed intervertebral foramen, narrowed vertebral canal, thickened articular process, articular process subluxation, articular process osteophyte, and telescoped sacral lamina. The CT characteristics of lumbosacral degenerative disease and discospondylitis were similar to those described in humans. In three dogs, CT findings at the site of cauda equina compression were consistent with congenital or developmental spinal stenosis, but the method of surgical exposure precluded confirmation. Epidural fibrosis (eight dogs) and multi-level CT abnormalities (six dogs) were identified but the cause@) and significance were unknown.

The progression of hip dysplasia was investigated in 116 military working dogs. Serial pelvic radiographs were graded for degree of dysplasia and degenerative joint disease (DJD). Norberg angles, angles of inclination, and joint space widths were measured. There was a significant correlation between the Norberg angle and the degree of dysplasia (p less than 0.0001). Angles of inclination and joint space width measurements did not demonstrate a correlation to canine hip dysplasia. Dysplastic dogs had a significant estimated risk for development of DJD compared to normal dogs (p less than 0.0001; odds ratio of 70.2). Dogs with normal hip conformation at 24 months of age or older did not develop moderate nor severe DJD.

Selection for a high (H) or low (L) incidence of tibial dyschondroplasia (TD) at 7 wk of age was practiced for four generations in broiler breeders using low intensity x-ray imaging (Lixiscope) for TD diagnosis. As a result, broiler lines with H or L incidence of TD at 7 wk of age were developed keeping a randomly selected control (C) broiler line. A total of 4,232 chicks were hatched representing 172 sires and 612 dams over four generations for the H, L, and C lines. The TD scores at 7 wk were collected on 4,056 broilers. Incidence of TD at 4 and 7 wk of age were studied in the C, H, and L lines of broilers. Direct response to selection in the H and L lines were estimated per generation and per weighted cumulative selection differential (WCSD). Total WCSD deviation from the C line for incidence of TD at 7 wk of age was 1.496 and -.42 units for the H and the L lines, respectively. The response per generation for incidence of TD at 7 wk of age for the H line was .153 +/- .028 units. The realized heritability for the H line for incidence of TD at 7 wk of age was .437 +/- .065. The incidence of TD was not significantly decreased in the L line at 7 wk of age.