A simple and humane model of inflammation, induced by the intradermal injection of 0.3 mL of sterile 2% carrageenan, was characterized in calves by measuring the volume of skin swelling plus histological analysis of skin biopsies. Carrageenan produced a biphasic increase in skin swelling, with an early edematous response followed by a more chronic cellular infiltrate. The swelling and sensitivity to pressure observed in the early response were suitable for testing the antiedematous and analgesic activity of a new nonsteroidal anti-inflammatory drug (NSAID), oxindanac. Pretreatment with intravenous oxindanac at doses from 0.5 to 8.0 mg/kg reduced the volume of swelling and this reached statistical significance (p < 0.05) at 2 mg/kg. The ED50 and ED90 values for inhibition of the peak swelling volume (4 h) were estimated to be 1 mg/kg and 2 mg/kg, respectively. These compare with an ED90 of 2.0 mg/kg for inhibition of serum TxB2 production, an index of platelet cyclo-oxygenase activity. The dose of oxindanac required for antiedematous activity correlated, therefore, with maximal inhibition of serum TxB2. The analgesic activity of oxindanac reached no clear maximum response, but statistically significant difference (p < 0.05) from placebo was reached with doses of 2 mg/kg and above. It is concluded that intradermal carrageenan produced a simple, humane and useful model for dose estimation of a new NSAID in calves.

Approximately 45 Holstein cows that were Mycobacterium paratuberculosis-positive on the basis of fecal culture results were maintained at any one time in a 210-cow dairy herd. Farm management participated in the New York State Paratuberculosis Eradication Program. Paratuberculosis-positive cows were grouped separately from paratuberculosis-negative cows, but they were otherwise managed identically. During a 1-year study, 180 paratuberculosis-negative cows and 113 clinically normal paratuberculosis-positive cows were identified. Quarter milk samples (n = 6,100) were aseptically collected for microbiologic culture of mastitis pathogens from paratuberculosis-negative cows, and 3,129 quarter samples were obtained from paratuberculosis-positive cows. Dairy Herd Improvement Association (DHIA) records were used to monitor milk somatic cell count linear scores, mature equivalent milk production, new mastitis infections, and chronic mastitis infections. For second-lactation cows greater than 100 days in milk production, and increasing with age beyond that point, paratuberculosis-positive cows had lower mature equivalent milk production than did negative herdmates. Rates of new and chronic mastitis infections, as measured by DHIA linear scores were significantly (P less than 0.05, P = 0.05, respectively) lower in cows with nonclinical paratuberculosis. Infected cows were cuffed from the herd at a faster rate than were paratuberculosis-negative herdmates. Therefore, paratuberculosis was associated with financial loss attributable to reduced milk production and increased culling of infected cows.

The hemodynamic effects of 2 dosages of ephedrine were studied in 6 dogs anesthetized with isoflurane only (end-tidal concentration equivalent to 1.5 times minimum alveolar concentration). Following instrumentation, baseline (time 0) measurements included heart rate (HR), respiratory rate, mean arterial blood pressure (MAP), cardiac output, and blood gas tensions. Cardiac index (CI), stroke volume (SV), systemic vascular resistance (SVR), arterial oxygen content (CaO2), and oxygen delivery and consumption (DO2 and VO2, respectively) were calculated. Three dogs were given ephedrine IV at a dosage of 0.1 mg/ kg of body weight, and 3 dogs were given ephedrine IV at a dosage of 0.25 mg/kg. Measurements were recorded at 5, 10, 15, 30, and 60 minutes. Each dog then received the alternate dosage of ephedrine, and measurements were again recorded at the same intervals. Effects of ephedrine varied with dosage. Neither dosage was associated with significant changes in pH, PaO2, PaCO2, VO2, or respiratory rate. Ephedrine at a dosage of 0.1 mg/kg caused transient significant increases in MAP, CI, SV, CaO2, and DO2, significant decreases in HR and SVR, and a late, slight decrease in CaO2. Ephedrine at a dosage of 0.25 mg/kg caused a greater and more prolonged increase in MAP, as well as increases in CI, SV, and SVR, and a decrease in HR. The higher dosage of ephedrine also caused a pronounced increase in hemoglobin concentration and CaO2, resulting in a 20 to 35% increase in DO2 throughout the 60-minute experiment.

Using a force plate, ground reaction force (GRF) patterns at take-off and landing between the hooves and the ground were recorded for all limbs of 5 Dutch Warmbloods jumping a 0.8-m vertical fence from the right-leading canter. Distribution of the GRF and force impulses over the 4 limbs at take-off and landing were considerably different from those recorded at the normal canter. At take-off, the propulsory GRF of the hind limbs were 3 to 5 times higher than at the normal canter, depending on the jumping technique of the horse. At landing, the propulsory GRF were mainly increased in the trailing forelimb and in both hind limbs. The vertical GRF amplitudes and force impulses were of similar magnitude to those at the canter, although increases up to 160% were found in the hind limbs of the horse with the worst jumping technique. The trailing forelimb carried the highest loads, up to twice the animal's body weight; GRF amplitudes tended to increase when higher fences were used. However, the jumping technique of the horse may have more influence, because an easily jumping horse could clear a 1.3-m-high fence with similar loads on the limbs.

Streak retinoscopy was performed by 5 ophthalmologists on 256 eyes (191 dogs) to determine their postoperative refractive state after cataract extraction. Aphakic and pseudophakic eyes that had been implanted with 1 of 5 intraocular lenses (IOL) with dioptric powers ranging from +14.5 to +38 diopters (D) were studied. By use of ANOVA, breed and body type of dog and individual performing refraction were found to have no detectable effect on final refractive state. Mean refractive state of aphakic eyes was +14.4 +/- 2.10 D. Mean refractive state for different IOL powers was as follows: +14.5 D IOL = +11.54 +/- 1.18 D (n = 13); +30 D IOL = + 5.15 +/- 1.18 D (n = 105); +34.0 D IOL = +3.5 D (n = 1); +36 D IOL +2.34 +/- 0.73 D 9 (n = 61); and +38 D IOL = +1.41 +/- 0.56 D (n = 28). Residual hyperopia ranged from +0.5 D to +2.5 D with +38 D IOL, and no eyes were myopic (overcorrected) by use of any of the IOL studied. linear regression analysis of refractive state on IOL power for aU dogs predicted that dioptric strength of +41.53 D was necessary to best approximate emmetropia for the population as a whole. Body type of the dog had only slight effect (< 1.0 D) on predicted optimal IOL power. Further linear regression analysis of the 7 breeds studied predicted variations from +39.62 to +43.14 D in IOL powers necessary to approximate emmetropia. Results of the study support the routine use of canine IOL with dioptric strength of approximately +41.5 D in circumstances in which preoperative biometry and keratometry are not practical. The findings further suggest that, for the specific population of dogs studied, most of the dogs could be corrected to near emmetropia by use of a small range of IOL dioptric strengths, irrespective of body type or breed.

After a detailed anatomic study to determine puncture sites, 10 cadaver elbows from 5 dogs were examined arthroscopicalty to study the normal intraarticular anatomy, as viewed from the medial side. Subsequent dissection revealed absence of neurovascular injury and only minor iatrogenic damage to the cartilage. The technique was clinically applied and evaluated in 13 dogs (26 joints). The dogs recovered without complications. The technique proved to be safe and reliable for direct examination of nearly the entire joint. More specifically, it allowed systematic inspection of the medial and lateral humeral condyles, the medial and lateral coronoid processes, the caudal and middle parts of the head of the radius, the olecranon (including the anconeal process), and the medial collateral ligament.

Effects of a change from a diet composed primarily of forage to a diet composed primarily of concentrate on abomasal antral and duodenal motility were assessed in 5 lactating Holstein cows. Antroduodenal motility was measured by use of 8 silver electrodes sutured to ther abomasum and duodenum, and abomasal emptying was assesssed by continuous measurement of intraduodenal pH. Both diets were fed to achieve a daily dry matter intake of 2.7 kg/100 kg of body weight. The abrupt change in diet did not alter antoduodenal myoelectric activity or abomasal emptying. Initiation of phase III of the migrating myoelectric complex in the proximal portion of the duodenum corresponded with a decrease in abomasal antral spiking activity and an increase in intraduodenal pH. Results suggest that a high concentrate diet alone does not adversely affect antroduodenal motility in adult dairy cattle.

Previously identified 39-, 50-, and 76-kd integral outer membrane proteins (IOMP) of Actinobacillus pleuropneumoniae, a respiratory tract pathogen, were separated by electroelution of sodium dodecyl sulfate-polyacrylamide gel electrophoresis-obtained fragments and their role in opsonophagocytosis by porcine leukocytes was investigated by flow cytometry of fluorescein-labeled A pleuropneumoniae. Using specific antisera, immunoblot analysis indicated that the 3 proteins were antigenically distinct. Antibodies against each IOMP have an important role as opsonins for phagocytosis by porcine leukocytes. The effect of using a combination of an 3 of the specific antisera was minimal. Antiserum absorbed against intact A pleuropneumoniae and Escherichia coli organisms indicated that the antibodies to the 39-, 50-, and 76-kd IOMP were specific for A pleuropneumoniae antigens. Nonheat-treated antiserum did not increase phagocytosis, compared with heat-inactivated antiserum, indicating that complement may not have a major role in opsonization of A pleuropneumoniae.

Postmortem examinations were done on 51 wood bison (Bison bison athabascae) killed as part of a multidisciplinary research project in the Mackenzie Bison Sanctuary, Northwest Territories, Canada, between 1986 and 1988. There was no gross, histological or bacteriological evidence of brucellosis or tuberculosis in these bison. Traumatic lesions were seen in one calf that had been attacked by wolves and a second calf that had been gored. Antibody titers to Brucella abortus were not found in sera from these 51 animals or an additional 112 wood bison that were chemically-immobilized or killed in the Sanctuary between 1986 and 1990. The combined prevalence of the diseases in the population could not have exceeded 5.95% for the necropsy survey to have missed finding at least one infected animal, and the prevalence of brucellosis in the population would have had to be less than 1.95% for the broader serological survey to have failed to find at least one reactor animal on the battery of tests. These results, and the cumulative epidemiological information on brucellosis and tuberculosis in bison, indicate that bovine brucellosis and tuberculosis are not enzootic in the wood bison population in and around the Mackenzie Bison Sanctuary, and suggest that the population is free of these diseases. However, this expanding population is at risk of contracting both diseases from the infected bison population in and around nearby Wood Buffalo National Park.

Selective parathyroidectomy (PTX) is preferred to thyroparathyroidectomy (TPTX) when specific effects of parathyroid hormone depletion are being studied. However, because of the anatomic proximity of thyroid and parathyroid glands, TPTX often is performed, leaving animals depleted of thyroxine (T4) and calcitonin as well as parathyroid hormone (PTH). In the present study, six normal dogs had parathyroid tissue and about seven-eighths of thyroid tissue removed. This quantity of thyroid tissue was inadequate to maintain normal serum T4 concentrations, despite allowance of 168 days for thyroid recovery. Five of six dogs with reduced renal mass had successful selective PTX and normal serum T4 concentrations at 28 days, when one-half or more of thyroid tissue was spared. We conclude that with attention to the surgical technique, selective PTX can be achieved in a high percentage of dogs and sufficient thyroid tissue spared to maintain euthyroidism.