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Abstract

CASE DESCRIPTION 3 Angus bulls, aged 2 to 3 years, with severe lameness of 2 to 4 weeks' duration and swelling proximal to the coronary band of the affected limb were evaluated after failing to respond to antimicrobial treatment.

CLINICAL FINDINGS Septic arthritis of a distal interphalangeal joint (DIPJ) was diagnosed in all 3 bulls on the basis of results of a physical examination, radiographic and ultrasonographic evaluations of the affected foot, and cytologic evaluation of synovial fluid from the affected DIPJ.

TREATMENT AND OUTCOME A novel modified abaxial approach was used to resect the infected distal sesamoid bone (navicular bone) and DIPJ of all 3 bulls. A window was created in the abaxial hoof wall that was lateral to and of sufficient size to extract the navicular bone. Following removal of the navicular bone, the DIPJ was debrided and resected and an orthopedic block was applied to the contralateral claw to minimize weight bearing on the infected digit. Two bulls also had a fiberglass cast applied to the affected limb to help immobilize the DIPJ. All 3 bulls recovered without complications, and 2 bulls were no longer lame, whereas the remaining bull was only mildly lame, at 4 to 5 weeks after surgery.

CLINICAL RELEVANCE The modified abaxial approach described for surgical resection of the DIPJ allowed extraction of the infected navicular bone without damage to the digital flexor tendons, something that cannot be achieved with other abaxial approaches. This approach is best used for patients without septic tenosynovitis.

Abstract

Objective—To evaluate the clinical response of sheep experimentally infected with Ehrlichia ruminantium to treatment with dimethyl sulfoxide (DMSO).

Animals—32 Merino crossbred sheep.

Procedure—16 sheep were infected with E ruminantium; 8 of these were treated twice daily with a 10% solution of DMSO (1 g/kg, IV) in polyionic fluid for 3 consecutive days. Treatment was initiated 2 days after the onset of clinical disease. Eight uninfected control sheep were similarly treated with DMSO. Placebo treatments (polyionic fluid administrations) were given to 8 infected and 8 uninfected sheep. Arterial and venous blood samples for blood gas and total plasma protein concentration measurements were collected daily (data from 5 days before until 6 days after onset of clinical disease were analyzed); physiologic variables and food consumption were also monitored. Gross pathologic findings and cytologic confirmation of the disease were recorded for the 16 infected sheep.

Results—Infected sheep treated with DMSO were able to maintain pulmonary gas exchange and had reduced pleural effusion and plasma protein loss, compared with infected untreated sheep that became hypoxic. Infected treated sheep developed an uncompensated metabolic acidosis. Uninfected treated sheep had reduced appetite, whereas uninfected untreated sheep maintained normal food intake.

Conclusions and Clinical Relevance—Results of DMSO treatment in sheep with experimentally induced heartwater disease indicated that administration of this agent, in combination with specific antimicrobial treatment, may be of some benefit in treatment of naturally occurring disease. (Am J Vet Res 2003;64;1542–1548)

Abstract

Objective—To determine whether ultrasound could be used to measure sole horn thickness in dairy cattle after claw trimming with an adaptation of the Dutch method.

Design—Case series.

Animals—24 adult Holstein dairy cows.

Procedure—Cows were restrained in a standing position, and claws were trimmed with an adaptation of the Dutch trimming method. B-mode ultrasonography was then performed. The transducer was placed on the sole just caudal to the apex of the toe and immediately medial and parallel to the abaxial white zone. The inner margin of the sole was identified as a thin hyperechoic line. Soles were considered to be too thin if sole horn thickness, determined by use of ultrasonography, was < 5 mm.

Results—Sole horn, underlying soft tissues, and the distal surface of the third phalanx were imaged in 151 claws. The inner margin of the sole could not be identified in 4 claws, and 37 claws could not be imaged because cows collapsed in the restraining chute. Mean ± SD sole thickness for all claws was 7.1 ± 1.3 mm. Only 1 sole was < 5 mm thick. The lateral front claws were significantly thicker than the medial hind claws.

Conclusions and Clinical Relevance—Results suggest that ultrasound imaging can be used to determine sole thickness in dairy cattle after routine claw trimming. (J Am Vet Med Assoc 2003;223:492–494)

Abstract

Objective—To determine whether administration of isoflupredone acetate (ISO) to healthy cows increases the frequency of severe hypokalemia and whether dexamethasone (DEX) has detectable mineralocorticoid properties.

Animals—33 cows at 20 to 25 days of lactation.

Procedures—Cows were randomly allocated to 5 treatment groups and received 2 IM injections (on days 0 and 2) of sterile saline (0.9% NaCl) solution (10 mL each), an injection of ISO (20 mg) or DEX (20 mg) followed by 10 mL of saline solution, or 2 injections of ISO or DEX. Milk production was measured, physical examinations were performed, and blood and urine samples were collected daily on days 0 through 7.

Results—Physical examination parameters did not differ among groups; however, 1 cow developed atrial fibrillation on day 4. Both corticosteroids significantly increased plasma glucose concentrations, and ISO significantly decreased plasma potassium concentrations and increased total carbon dioxide concentrations with time. One dose of ISO decreased mean plasma potassium concentration by 25% on day 2, compared with day 0, and severe hypokalemia (serum potassium concentration < 2.3 mEq/L) developed in 1 of 6 cows. Mean plasma potassium concentration was 46% lower on day 3 than on day 0 in cows receiving 2 doses of ISO, and 5 of 7 cows became severely hypokalemic. Mean urinary fractional excretion of potassium significantly increased from that on day 0 in cows receiving 2 doses of ISO.

Conclusions and Clinical Relevance—Both corticosteroids had glucocorticoid activity; however, only ISO had mineralocorticoid activity. Compared with saline solution, administration of 2 doses of ISO significantly increased the frequency of severe hypokalemia.