Supplemental dietary biotin for prevention of lesions associated with aseptic subclinical laminitis (pododermatitis aseptica diffusa) in primiparous cows.

OBJECTIVE: To evaluate, in primiparous cows, the effect of dietary biotin supplementation on severity of lesions of aseptic subclinical laminitis. ANIMALS: 100 primiparous cows in a 800-cow commercial dairy herd. PROCEDURE: Cows were assigned after calving to a biotin-supplemented (20 mg/head/d) or control group on an alternating basis. Digits 3 and 4 of the left forelimb and right hind limb were examined at a mean of 25, 108, and 293 days after parturition. Toe length, hoof angle, and heel depth were measured, and hooves were examined for solear hemorrhage, yellow solear discoloration, separation of the white line, and heel erosion. Serum and milk biotin concentrations were also measured. RESULTS: Serum biotin concentrations were significantly higher for supplemented than for control cows. During the second examination, prevalence of separation of the white line of digits 3 and 4 of the hind limb and digit 4 of the forelimb was lower for supplemented than for control cows. Mean decrease in heel depth between the first and third examinations was approximately twice as great for digit 4 of the forelimb and 4 times as great for digit 3 of the forelimb in supplemented, versus control, cows. Other differences were not found. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that supplemental dietary biotin may have a beneficial effect on hoof health in intensively managed primiparous dairy cows.

Multifocal polyostotic aneurysmal bone cysts in a llama.

A 3.3-year-old 125-kg castrated male llama was evaluated because of acute non-weight-bearing lameness on the left hind limb. Physical examination revealed crepitus in the midportion of the femur. On radiographs, a comminuted middiaphyseal fracture was seen. There was also a region of bone lysis with cortical thinning and expansion in the distal metaphysis and epiphysis of the left femur. Multiple small circular lesions were observed in the proximal metaphysis of the left femur, and the proximal portion of the left tibia appeared irregular. The owner elected to pursue treatment, and the fracture was repaired with 2 compression plates. Multiple bone biopsy specimens were obtained and submitted for bacterial culture and histologic examination. Cultures yielded neither bacteria nor fungi. Histologic examination revealed fibrous connective tissue, normal appearing cortical bone, and an absence of medullary structures. The llama was maintained in a hind-limb sling for 14 days after surgery, at which time follow-up radiography revealed a comminuted fracture of the proximal portion of the femur. The llama was euthanatized, and multifocal polyostotic aneurysmal bone cysts were found in the proximal and distal metaphyses of the left femur and tibia. Cysts were lined by fibroblasts or endothelial-like cells.

Disseminated Halicephalobus deletrix infection in a horse.

A 13-year-old Quarter Horse gelding was referred for evaluation of a draining tract and fracture of the right hemimandible of 4 weeks' duration. Two days prior to admission, the horse had developed pigmenturia. Radiography of the mandible revealed a fracture of the vertical ramus of the right hemimandible, loss of the right lower second premolar, and osteomyelitis involving an extensive portion of the hemimandible. Ultrasonography of the left kidney revealed loss of normal renal architecture. Histologic examination of tissue obtained from the right hemimandible revealed granulomatous osteomyelitis and multiple metazoan parasites identified as Halicephalobus deletrix. The horse was treated with antimicrobial and deworming agents, and the mandible was surgically debrided. The horse became atactic 8 days after surgery and was euthanatized. Necropsy identified parasitic migration in the right hemimandible, kidneys, and CNS.