Corynebacterium pseudotuberculosis phospholipase D (PLD) significantly affected viability of ovine neutrophils after 24 hours' exposure, This effect was more marked in cells that ingested PLD emulsified in oil. Treatment of neutrophils with PLD significantly (P < 0.05) reduced the ability of these cells to migrate toward activated sheep serum. The PLD was not chemotactic, but it activated normal sheep serum, producing factors that were chemotactic for neutrophils.

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.

One hundred two dogs without known gastric lesions were evaluated to establish a reference range of gastric rugal fold thickness (millimeters). Mucosal folds were measureable for 63 examinations, and the length of the second lumbar vertebra was measured for 61 of the 63 (centimeters). Body weight was available in the case records of 29 dogs. Measurements of the mucosal folds were related to body weight (n = 29) and length of the second lumbar vertebra (n = 61) by use of linear regression analysis. Reference range of normal gastric mucosal fold thickness, 1 to 8 mm, was defined by this study for dogs of any breed weighing between 2 and 50 kg.

Serum triiodothyronine autoantibody (T3 AA), triiodothyronine (T3), and thyroxine (T4) concentrations were determined in 45 canine sera containing substantial amounts of thyroglobulin autoantibodies (Tg AA); sera also were assayed to investigate the ability of free T3 to inhibit Tg AA binding to canine Tg. Serum T3 AA concentrations defined 2 groups of sera; 28 sera had low T3 AA concentration (less than or equal to 20 ng/ml) and 17 sera had high T3 AA concentration (greater than or equal to 250 ng/ml). Direct linear correlation between T3 AA concentration and apparent serum T3 concentration was observed (r = 0.75). Serum with low T3 AA concentration had apparent T3 concentration that was significantly (P < 0.01) lower than that in serum with high T3 AA concentration. Mean serum T4 concentration was not significantly different between serum with low or high T3 AA concentration. Mean Tg AA activity was significantly (P < 0.05) lower in serum with low T3 AA concentration than in serum with high T3 AA concentration. Addition of free T3 to serum significantly (P < 0.05) decreased detectable activity of Tg AA in both groups of sera. However, significant difference in magnitude of the reduction was not observed between sera with low or high T3 AA concentration. Results indicate that a fraction of Tg AA recognizes T3-containing epitopes in Tg. Increased prevalence of T3 AA for serum with high Tg AA activity indicates that T3 AA may be another valid indicator of lymphocytic thyroiditis. These antibodies may be generated against the hormonogenic epitopes of Tg.

The effect of prior Rhodococcus equi-induced pneumonia on pulmonary health was investigated in 5 horses (< 24 months old) using endoscopy, radiography, hematologic and bronchoalveolar lavage analyses, and pulmonary function testing. Rhodococcus equi-induced pneumonia had been diagnosed in principal horses when they were foals. Diagnosis was based on positive results of transtracheal aspiration and thoracic radiography at the time of initial clinical examination. Results of reevaluation of the respiratory system of these horses (R+) were compared with those of 5 age-matched healthy horses (R-) that lacked clinical or historical evidence of foalhood pneumonia. Significant differences in variables between the 2 groups of horses were not evident. In both groups, most horses had radiographic evidence of an accentuated bronchointerstitial pattern, although results of analysis of bronchoalveolar lavage specimens were normal and mononuclear cells predominated. Variability in results of the pulmonary function tests was observed within and between the 2 groups of horses. Only normatized dynamic lung compliance was slightly lower in the previously infected horses, but this difference was not significant. We concluded that horses previously infected with and successfully treated for R equi-induced pneumonia do not have detectable evidence of residual lung damage.

Limb symmetry was evaluated by measuring ground reaction forces in 2 groups of normal-gaited dogs at a trot. Data were collected from 2 groups of 21 dogs trotted at dog/handler velocities of 1.25 to 1.55 m/s and 1.85 to 2.05 m/s, respectively. Of these dogs, 9 participated in both groups to allow comparison of data at both velocities. Additionally, 16 of the dogs in group 1 were measured in 2 directions of movement to determine whether directional dependence was present. Collected data were then applied to 3 described symmetry indices. Each index was easy to calculate, but all had limitations. A major limitation was variation in magnitude of ground reaction forces measured between the different axes and the effect of this variation on precision of the derived indices. Vertical ground forces provided the most consistent symmetry indices, in part because of their large magnitude. The indices indicated that no dog had perfect right-to-left symmetry during a trotting gait. Statistical differences were not found in any of the measurements of directional dependence. Likewise, comparing symmetry data in dogs trotted at both velocities indicated no significant differences in any axis. However, further analysis of the data revealed the actual amount that a variance attributable to right-left limb variation was negligible. Most of the variance was attributable to trial variation. Thus, the aforementioned indices, which use nonconsecutive footfall methods to evaluate limb symmetry, actually measure principally trial variation and not limb-to-limb variation.

Renal clearance procedures were performed on adult mixed-breed dogs with a wide range of renal function. Endogenous creatinine clearance was computed after analyzing plasma and urine for creatinine by use of 2 methods, PAP and kinetic Jaffe. For 20-minute clearance procedures, [14C]inulin clearance was measured simultaneously with endogenous creatinine clearance. For 111 twenty-minute clearance procedures performed on 24 dogs, [14C]inulin clearance was highly correlated with creatinine clearance for both methods of creatinine analysis (R2 = 0.979 for [14C]inulin-PAP; R2 = 0.943 for [14C]inulin-Jaffe). The absolute values for PAP and [14C]inulin clearance were nearly the same (PAP-to-[14C]inulin clearance ratio = 1.03 +/- 0.08), but those for Jaffe clearance were substantially less than those for [14C] inulin clearance Jaffe-to-[14C]inulin clearance ratio = 0.88 +/- 0.10). The Jaffe-to-[14C] inulin clearance ratio was inversely correlated with degree of renal function (R2 = 0.464), whereas the PAP-to-[14C]inulin clearance ratio was not correlated with degree of renal function (R2 = 0.060). Thus, Jaffe-determined creatinine clearance varied, in relation to [14C] inulin clearance, depending on degree of renal function. In 4 clinically normal dogs, 20-minute and 24-hour sample collections analyzed by use of the PAP method gave clearance values significantly greater, for both periods, than did Jaffe analyses. The PAP-determined creatinine clearance values were less than, but not significantly different from 20-minute exogenous creatinine clearance values determined 10 days after 24-hour collections. For 20-minute and 24-hour collections, the difference in clearance values between the PAP and Jaffe methods was attributable mostly to lower plasma creatinine values for the PAP method (mean +/- SEM, plasma PAP-to-Jaffe ratio = 0.798 +/- 0.053). However, urine creatinine values also were less by use of the PAP method (urine PAP-to-Jaffe ratio = 0.943 +/- 0.103). We conclude that PAP-determined creatinine clearance reliably measured glomerular filtration rate during 20-minute collections, and probably during 24-hour collections as well. By contrast, Jaffe-determined creatinine clearance underestimated glomerular filtration rate by a variable amount.

To evaluate the effect of ketoprofen on fecal output during secretory diarrhea, 16 calves were given approximately 200 micrograms of heat-stable Escherichia coli enterotoxin by suckling on 2 occasions. On one day, treatment was not administered. On the other day, either 3 mg of ketoprofen/kg of body weight (n = 8) or 6 mg of ketoprofen/kg (n = 8) was administered 1 hour before and 3 hours after administration of enterotoxin. Fecal output was no different after 8 or 24 hours from calves given 3 mg/kg, but fecal output was less at 8 hours and 24 hours for calves given 6 mg/kg (P = 0.0588), compared with the control day.

Age and species reportedly affect the pharmacokinetic variables of nonsteroidal anti-inflammatory drugs. We determined the effect of age on flunixin pharmacokinetic variables in foals during the first month of life. We also estimated the physiologic activity of the drug in neonatal foals by determining the effect of flunixin on thromboxane production during clotting of blood taken from the foals. Flunixin disposition and clearance were determined after IV administration of 1.1 mg of drug/kg of body weight to 5 healthy foals when they were 24 to 28 hours, 10 to 11 days, and 27 to 28 days old. The area under the curve (2,471 micrograms.min/ml), mean residence time (477 minutes), and zero-time intercept of the elimination phase (4,853 ng/ml) were significantly (P = 0.05) greater, the elimination half-life (339 minutes) and slope of the elimination phase (0.002 L/min) were significantly (P = 0.05) longer, and total body clearance (0.482 ml/min/kg) and zero-time intercept for the distribution phase (2,092 ng/ml) were significantly (P = 0.05) lower at 24 to 28 hours. At each age, a biexponential equation was best fitted to the plasma flunixin concentration from each foal. Thromboxane B2 production during clotting of blood was significantly (P = 0.05) suppressed for 12 hours after flunixin meglumine administration at all ages. Therefore, it appears that although age does alter the disposition and elimination of flunixin in neonatal foals, this effect may be of little consequence because the drug's physiologic activity in foals appears similar to that in mature horses.

Effects of phenylbutazone (PBZ) and furosemide (FUR) on the respiratory tract of horses were evaluated, focusing on bronchial responsiveness. Four healthy Thoroughbreds were used and data were analyzed by use of a Latin square design. Histamine provocation tests (0.5, 1, 2, and 4 micrograms/kg/min, IV) were done: (1) without prior treatment with PBZ or FUR, (2) 30 minutes after administration of PBZ (8 mg/kg, IV), (3) 1 hour after administration of FUR (1 mg/kg, IV), and (4) after administration of PBZ plus FUR. Pulmonary function tests (dynamic compliance, resistance, respiratory frequency, and tidal volume) and heart rate were monitored throughout the experiments. Phenylbutazone did not influence basal pulmonary function test results, whereas FUR caused a significant (P < 0.05) increase in dynamic compliance and decrease in resistance. Histamine infusion resulted in a dose-dependent decrease in dynamic compliance and a dose-dependent increase in resistance, respiratory frequency, and heart rate. Phenylbutazone administration significantly (P < 0.05) attenuated most of the changes induced by histamine, whereas FUR had less protective action. Administration of PBZ plus FUR before administration of histamine was less effective than administration of PBZ alone.