A study was designed to compare use of an numerical rating scale (NRS) and a visual analogue scale (VAS) for subjective assessment of lameness, using sheep as a model. The NRS consisted of 5 divisions, 0, 1, 2, 3, and 4; 4 of these divisions (1-4) described lameness. The VAS used a 100-mm horizontal line with vertical bars at either end; one end was labeled 'sound' and the other was labeled 'could not be more lame.' Two independent observers graded lameness in 62 sheep, and between- and within-observer differences were assessed for each scoring system to compare the NRS with the VAS. Results indicated no significant differences between the 2 observers scoring lameness, using either the VAS or the NRS. The scores obtained, using the VAS, were not normally distributed, although differences between scores for the 2 observers were. The NRS scores followed a normal distribution pattern. Investigation of repeated measurement for the same sheep, using both scales, revealed no significant difference between either. A comparison of the NRS and VAS scores made by each observer indicated that although correlation was good (observer 1; r = 0.94; observer 2; r = 0.95), there was not perfect agreement. The maximal NRS score of 4 was associated with VAS values > 68 mm, indicating that the NRS divisions did not reflect equal increases in lameness. The VAS and NRS scores for each observer were highly reproducible, although they were more variable for sheep that were regarded as moderately lame. Results indicate that although the NRS and VAS compared favorably with respect to repeatability, reproducibility, and use by 2 observers, the VAS is inherently more sensitive. In addition, the NRS and VAS should not be used interchangeably.

Pharmacokinetic variables of phenolsulfonphthalein (PSP) were determined in sheep after rapid IV injection and IV infusion to steady state. In Suffolk wethers, an average of < 75% of an IV administered dose was eliminated in urine, indicating that measures of systemic clearance overestimate renal clearance in this species. Furthermore, PSP elimination from plasma was more rapid in Suffolk than Rambouillet wethers and, in Suffolk ewes, systemic clearance decreased from mean +/- SD 7.8 +/- 0.3 ml/min/kg of body weight to 4.7 +/- 1.1 ml/min/kg at steady-state plasma concentration of 2.4 +/- 0.3 and 151.3 +/- 31.8 micrograms/ml, respectively. These observations indicate that, similar to that in other species, systemic clearance of PSP in sheep is concentration-dependent and that significant differences may exist between breeds.

An agar gel immunodiffusion (AGID) test was used over a 3-year period to examine 1,871 serum samples from sheep representing 5 Mycobacterium paratuberculosis infected flocks and 4 flocks presumed to be uninfected. Of 1,032 sheep, 31 had positive AGID test results (scoring 1 to 5), and 23 of these 31 were ecropsied. Infection with M paratuberculosis was confirmed by 1 or more of the following findings: observation of typical lesions on histologic examination of sections of ileum or ileocecal lymph nodes, observation of clumps of acid-fast bacteria in mucosal smears of ileum, and isolation of the organism from feces or tissue. False-positive results on AGID testing were not found in sheep from flocks known to have exposure to Cotynebacterium pseudotuberculosis. Diarrhea in infected sheep was observed infrequency; chronic, severe weight loss was the most common sign observed. On histologic examination of tissues from 20 infected sheep, 16 (80%) had diffuse lesions of the ileum and 13 (65%) had acid-fast bacteria in areas of ileal inflammation; 4 had discrete granulomas and peripheral lymphocytic infiltrates in the ileum. Sheep with diffuse lesions tended to have higher mean scores on AGID testing and examination for acid-fast bacteria, compared with those from sheep with more discrete lesions. Bacteriologic culture yielded M paratuberculosis from only 3 sheep with paratuberculosis. On the basis of results of this study, we suggest that the nature of the response to infection with M paratuberculosis may influence the results of diagnostic tests for paratuberculosis, and that AGID testing may be useful to identify M paratuberculosis infection in sheep with chronic weight loss and in flock-screening programs.

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.

Static lung compliance, static lung volumes, and transfer factor for carbon monoxide were measured in 12 anesthetized adult Texel ewes seropositive for maedi-visna virus (MVV) and in 11 breed-, sex-, and age-matched seronegative controls. Median static lung compliance in MVV-infected sheep (1.24 L.kPa-1; range, 0.27 to 2,20 L.kPa-1) was not significantly different from that in controls (1.58 L.kPa-1; range, 0.82 to 2.08 L.kPa-1). Median body weight of MVV-infected sheep (56 kg; range, 40 to 75 kg) was significantly (P < 0.05) less than that of controls (65 kg; range, 53 to 87 kg). Median effective alveolar lung volume in MVV-infected sheep (3.36 L; range, 1.44 to 4.52 L) was significantly (P < 0.01) less than that in controls (4.12 L; range, 3.75 to 4.90 L). Median effective end expiratory lung volume in MVV-infected sheep (1.20 L; range, 0.56 to 1.99 L) was significantly (P < 0.001) less than that of controls (1.98 L; range: 1.76 to 2.78 L). Median lung volumes expressed per unit of body weight did not differ significantly between the groups. Median single-breath transfer factor for carbon monoxide in MVV-infected sheep (7.89 mmol-min-1.kPa-1; range, 3.45 to 12.74 mmol.min-1.kPa-1) was significantly (P < 0.001) less than that in controls (14.10 mmol.min-1-kPa-1; range, 10.02 to 18.30 mmol.min-1-kPa-1). Median transfer factor expressed per liter of alveolar volume in MVV-infected sheep (2.44 mmol.min-1-kPa-1.L-1; range, 1.28 to 3.72 mmol.min-1-kPa-1.L-1) gm significantly (P < 0.05) less than that in controls (3.22 mmol.min-1-kPa-1.L-1; range, 2.47 to 3.74 mmol.min-1-kPa-1.L-1). These findings indicate that static lung volumes and transfer factor for carbon monoxide are significantly decreased in adult sheep naturally infected with MVV.

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.

Each of 5 US-origin serotypes of bluetongue virus (BTV) was inoculated into a separate pair of sheep. The duration of each animal's ensuing viremia was monitored, using a BTV serogroup-specific nested polymerase chain reaction (PCR) method and an embryonating chicken egg (ECE) inoculation procedure. Mean duration of viremia was 100 and 38 days for the PCR and ECE methods, respectively. This difference was significant (P < 0.001) and documents a more prolonged viremia in virus-exposed sheep than has been reported. A dual internal oligonucleotide solution hybridization procedure was developed for the rapid (2 hours) colorimetric detection and identification of BTV-specific PCR products. This enzyme-linked oligonucleotide sorbent assay (ELOSA) relied on annealing of separate biotinylated and fluoresceinated probes to the amplified BTV nucleic acid; these complexes were captured on streptavidin-coated microtitration wells and were detected, using a horseradish peroxidase-labeled antifluorescein antibody conjugate. End-point dilution analyses of PCR products indicated that the ELOSA was more sensitive than gel electrophoretic or comparable colorimetric slot-blot hybridization techniques. The BTV PCR-ELOSA system represents a more sensitive and expeditious means of diagnosing BTV-induced viremia than does the ECE procedure currently used. The combination of ELOSA with PCR should facilitate practical application of nucleic acid technology to diagnostic veterinary medicine.

To clarify the oxidant defense functions of reduced glutathione (GSH) in erythrocytes, the effect of GSH deficiency on in vitro oxidant defense was studied, using GSH-deficient sheep erythrocytes (low-GSH cells). The formation of Heinz bodies in low-GSH cells was higher than that in high-GSH cells when the cells were incubated with an oxidant drug, acetyl-phenylhydrazine (APH). Artificial depletion of GSH by 1-chloro-2,4-dinitrobenzene in high-GSH cells resulted in increased Heinz body formation in these cells incubated with APH. Furthermore, high negative correlation was observed between Heinz body formation and GSH content in sheep erythrocytes exposed to APH. These results clearly indicate that erythrocyte GSH is indispensable for erythrocyte defense against oxidative damage induced by APH, and support the previous observations that sheep with low-GSH erythrocytes were more susceptible to oxidative agents than were sheep with high-GSH erythrocytes.

Anesthesia was induced and maintained in 6 Suffolk wethers by continuous IV infusion of guaifenesin (50 mg/ml), ketamine (1 mg/ml), and xylazine (0.1 mg/ml) in 5% dextrose in water (triple drip) to assess the anesthetic and cardiopulmonary effects. All sheep were positioned in right lateral recumbency. Dosages of triple drip used for induction and maintenance of anesthesia were 1.2 +/- 0.02 ml/kg and 2.6 ml/kg/h, respectively. Lack of gross purposeful movement of sheep to electrical stimulation indicated that analgesia and muscular relaxation induced by triple trip were adequate for surgical procedures. Heart rates and arterial blood pressure remained unchanged from baseline values during a 1-hour period of anesthesia. Arterial blood pressures were measured indirectly, using an inflation cuff placed over the metatarsal artery at the heart level. Significant decrease in arterial partial pressure of O2 (PaO2), coupled with an increase in arterial partial pressure of CO2 (PaCO2), from baseline values was observed throughout the course of the study. Decrease in PaO2 was observed concomitantly with significant (P < 0.05) increase in respiration rate. Changes in arterial blood gas tensions observed in this study were attributed to respiratory depressant effect induced by anesthetic drugs and right-to-left shunting, perfusion/ventilation mismatch, or both caused by right lateral recumbency. Administration of 100% O2 via the endotracheal tube reduced the magnitude of the decrease in PaO2. All sheep recovered smoothly and stood within 96.3 +/- 48.9 minutes after termination of triple drip administration.

A study was designed to compare use of an numerical rating scale (NRS) and a visual analogue scale (VAS) for subjective assessment of lameness, using sheep as a model. The NRS consisted of 5 divisions, 0, 1, 2, 3, and 4; 4 of these divisions (1-4) described lameness. The VAS used a 100-mm horizontal line with vertical bars at either end; one end was labeled 'sound' and the other was labeled 'could not be more lame.' Two independent observers graded lameness in 62 sheep, and between- and within-observer differences were assessed for each scoring system to compare the NRS with the VAS. Results indicated no significant differences between the 2 observers scoring lameness, using either the VAS or the NRS. The scores obtained, using the VAS, were not normally distributed, although differences between scores for the 2 observers were. The NRS scores followed a normal distribution pattern. Investigation of repeated measurement for the same sheep, using both scales, revealed no significant difference between either. A comparison of the NRS and VAS scores made by each observer indicated that although correlation was good (observer 1; r = 0.94; observer 2; r = 0.95), there was not perfect agreement. The maximal NRS score of 4 was associated with VAS values > 68 mm, indicating that the NRS divisions did not reflect equal increases in lameness. The VAS and NRS scores for each observer were highly reproducible, although they were more variable for sheep that were regarded as moderately lame. Results indicate that although the NRS and VAS compared favorably with respect to repeatability, reproducibility, and use by 2 observers, the VAS is inherently more sensitive. In addition, the NRS and VAS should not be use interchangeably.