The purposes of this study were to evaluate the efficacy of metoclopramide to aid passage of a flexible endoscope into the duodenum of dogs, and to determine whether the effect of metoclopramide is dependent on dose. In a randomized, blinded, complete-block design, 6 healthy dogs were anesthetized, then each was given saline solution or 1 of 4 doses of metoclopramide on different days. The ease of passage of a flexible, fiberoptic gastroscope through the pylorus was assessed independently by 3 endoscopists. Administration of metoclopramide hydrochloride at a dosage of 0.4 mg/kg of body weight, IV, made passage of a flexible endoscope into the duodenum significantly (P = 0.009) more difficult than when saline solution was administered; however, dosages of 0.1, 0.2 and 0.8 mg of metoclopramide/kg did not (P = 0.489, 0.842, and 0.092 respectively). It was concluded that metoclopramide did not facilitate, and at one dosage hindered, successful passage of a flexible endoscope into the duodenum of healthy dogs under the conditions of the study. Metoclopramide, therefore, cannot be recommended as an aid for passage of a flexible endoscope into the duodenum of dogs.

The effect of feeding monensin, with or without dry hay plus wilted forage, on ruminal formation of 3-methylindole (3MI) was investigated in pastured cattle. Eighty-two cows were allotted to 3 groups. Cows of group-1 served as controls and were given a daily energy supplement (1 kg/head) without monensin for 1 day before and for 7 days after being allowed access to lush pasture. Cows of groups 2 and 3 were given the same daily energy supplement, which also contained monensin (200 mg/kg of supplement). Cows of group 3 also were fed dry hay for 5 days before the start of the study and continued to be given supplemental hay for 4 days after being allowed access to lush pasture containing a layer of wilted forage. Ruminal 3MI and indole concentrations increased on day 1 after all groups were allowed access to lush pasture. By day 7, 3MI concentration in all cows had decreased to pregrazing concentration. Indole concentration did not reach pregrazing concentration until day 10 for cows of groups 1 and 2. Group-3 cows had pregrazing indole concentration on day 7. Ruminal indole concentration did not differ (P > 0.05) between groups 1 and 2. Ruminal indole concentration was lower (P < 0.01) in group-3 cows on all sample collection days, except day 10, compared with that in the other groups. Monensin reduced (P < 0.01) 3MI formation on days 1 and 7 in group-2 cows, compared with group-1 cows. Group-3 cows had lower 3MI concentration than did group-1 cows (P < 0.01) on days -1, 1, 4, and 7. Monensin, when fed with dry hay and wilted forage, reduced (P < 0.01) 3MI formation on days 4 and 7 in group-3 cows, compared with cows that were only given monensin (group 2). Group-3 cows also had lower (P < 0.05) 3MI concentration, compared with group-2 cows on day 1. Results indicated that monensin reduced ruminal formation of 3MI. Feeding dry hay and wilted forage to cattle during the change to lush pasture resulted in further reduction in the amount of 3MI formed by ruminal microorganisms. To maximize the effectiveness of monensin in reducing 3MI formation, dry hay plus wilted forage should be fed to pastured cattle for at least 4 days after they are allowed access to lush pasture.

An ELISA was developed and tested to detect antibodies to Eperythrozoon suis in swine. Results were compare with those of the indirect hemagglutination (IHA) test. Antigen isolated from swine heavily infected with E suis was used for both tests. Comparison of the ELISA with the IHA test revealed a significant (P < 0.001) correlation between results. Of 114 samples obtained from 9 swine infected with E suis, 8 7.7% were seropositive (titer greater than or equal to 200) via the ELISA, and 80.7% were seropositive (titer greater than or equal to 20) via the IHA test. The sensitivity of the ELISA was greater than that of the IHA test. All blood samples obtained from specific-pathogen-free swine tested negative for E suis antibody. Cross-reactions were not observed between E suis antigen and antisera against various swine and cattle disease agents using ELISA. We concluded that the ELISA may be used for rapid and effective diagnosis of infection with E suis in swine.

Brain, spleen, and selected lymph nodes from sheep with clinical signs of scrapie were analyzed for presence of proteinase K-resistant protein (PrP-res). Diagnosis of scrapie on the basis of detection of PrP-res was compared with diagnosis on the basis of histologic evaluation of the brain from clinically affected or exposed sheep. Proteinase K-resistant protein was found in every brain that was histologically positive for scrapie, and in addition, was found in the brain of several clinically positive sheep that were not diagnosed as scrapie-positive by histologic evaluation. Proteinase K-resistant protein was also found in 87% of the spleens and lymph nodes from sheep that had PrP-res detected in brain homogenates. Therefore, analysis of sheep brain, spleen, or lymph nodes for PrP-res provided a diagnostic approach that was superior to histologic examination alone for detection of naturally scrapie agent-infected sheep.

Macromolecular permeability of the small intestine was tested in four 3-week-old gnotobiotic pigs inoculated with porcine rotavirus strain RV277 (group A). Pigs were administered 125I-labeled polyvinylpyrrolidone (molecular weight [mol wt], 40,000) orally 1 day before and 2 and 24 hours after virus inoculation, and blood samples were obtained every 6 hours. Eight hours after rotavirus inoculation, pigs had watery diarrhea. Increased permeation of 125I-labeled polyvinylpyrrolidone was not observed after clinical signs of infection had developed. Serum total protein and urea nitrogen concentrations increased slightly at the end of the study, probably as a consequence of dehydration. Differences in blood glucose concentration were not seen. At 48 hours after viral inoculation, macromolecular permeability was tested morphologically by injecting horseradish peroxidase (mol wt, 40,000) into the jejunal lumen just distally to the ligamentum colicoduodenale. After an incubation period of 20 minutes, small segments of jejunum were obtained for stereomicroscopic, histologic, and ultrastructural investigations. Moderate hyperregenerative villus atrophy was found. Ultrastructural changes of the villus epithelium were minor, and increased macromolecular permeation was not observed.

Body condition scoring (using a 5-point with quarter-point divisions) was performed on 66 Holstein dairy cows that began their second or later lactation in August, September, or October 1988. Cows' body condition was scored beginning on postpartum day 4 (+/- 1) and subsequently at postpartum days (+/- 1) 18, 32, 46, 60, 73 and 87. Blood samples were obtained on the same dates. Reproductive health examinations were conducted by 1 of 2 veterinarians beginning at postpartum day 21. Reproductive performance was evaluated in relation to body condition score and serum urea nitrogen and cholesterol concentrations. Number of days to first recorded signs of estrus and first breeding were not related to body condition score at calving, amount of condition loss, cumulative 80-day milk yield, or 305-day fat corrected milk yield. Cows that calved with body condition score greater than or equal to 3.50 required more days to conceive. Cows losing > 0.75 points of condition had longer days of conception. Body condition score at calving and amount of condition lost were not related to services per conception or diagnosis of follicular cyst. Cumulative 80-day milk yield was not related to days to conception or services per conception. Cows that produced greater than or equal to the mean 305-day milk yield required more services and had longer days to conception than cows that produced < the mean 305-day milk yield. Cows with diagnosis of ovarian follicular cysts had greater cumulative 80- and 305-day milk yields than did cows that were not diagnosed with follicular cysts. Cows conceiving with less than or equal to 2 services did not differ in average daily milk production, body condition score, or serum urea nitrogen concentration from cows conceiving with > 2 services, but cows that conceived with less than or equal to 2 services had higher serum cholesterol values than did cows requiring more services.

The effect of urine pH on plasma disposition of ampicillin sodium was evaluated. A single dose of 10 mg/kg of body weight was administered IV to Thoroughbreds with alkaline (pH > 8.0) or acidic (pH < 4.5) urine. Urine alkalinity was achieved and maintained by oral administration of up to 400 mg of sodium bicarbonate/kg/d, and acidity was achieved and maintained by oral administration of up to 400 mg of ammonium chloride/kg/d. Ampicillin sodium was measured in the plasma of horses by use of an agar diffusion microbiological assay with Bacillus subtilis as the test organism. The plasma disposition kinetics of ampicillin sodium best fitted a 2-exponential decay pattern, and statistically significant differences were not evident in elimination half-life, area under the plasma concentration time curve, volume of distribution, or body clearance rate between horses with alkaline or acidic urine. Results indicate that changes in urine pH over a range encountered in clinically normal horses are unlikely to affect plasma pharmacokinetic variables of ampicillin sodium after IV administration of the drug.

Viscosity of synovial fluid (SF) from 29 clinically normal horses was determined by use of a rotational cone and plate microviscosimeter. Total protein concentration in the SF of the 29 horses, as measured with a refractometer, was < 2.5 g/dl. When the Coomassie brilliant blue test was used to determine total protein concentration in SF for 15 horses, the mean value was 1,088 mg/dl. Viscosity values at 60, 30, 12, 6, 3, and 1.5 revolutions/min (rpm) spindle speed were 4.41 +/- 1.54 centipoise (cp), 5.29 +/- 1.94 cp, 6.76 +/- 2.76 cp, 8.52 +/- 4.27 cp, 10.41 +/- 6.30 cp, and 13.07 +/- 9.05 cp, respectively. Synovial fluid viscosity increased with decreasing rpm and shear rate, but the shape of the curve for each horse fitted the asymptotic curve. The rotational cone and plate microviscosimeter was an accurate instrument in measuring SF viscosity at multiple rpm or shear rates in horses. The values obtained on clinically normal horses in this study will serve as a baseline for comparison in the evaluation of horses with joint disease.

Systemic and pulmonary antibody responses of calves to Pasteurella haemolytica were evaluated by measuring immunoglobulin production in blood for 9 days and in pulmonary lavage fluid for 7 days after intrapulmonary inoculation. Clinical signs, pulmonary lesions, pulmonary and systemic inflammatory response, and amount of antigen in lavage fluid were used to evaluate the response of calves to challenge with P haemolytica. The pulmonary response consisted of production of IgG, IgE, and IgM antibodies to P haemolytica antigens and a 17- to 68-fold increase of cells in lavage fluid 8 hours after inoculation, with a gradual decrease toward normal. Antibodies of the IgM isotype to P haemolytica were demonstrated as early as 8 hours through 7 days after inoculation in 3 of 3 calves. Of the anti-P haemolytica isotypes, IgM was found in the highest concentration. In all of the inoculated calves, IgE was found 1 to 2 days after inoculation, and IgG was found in 2 of 3 inoculated calves from day 1 through 7 after inoculation. Detection of IgG correlated with smaller pulmonary lesions. Immunoglobulin A was not detected in lavage fluid. Serum was evaluated for IgG and IgM antibody response to P haemolytica. Specific IgM was detectable 5 days after inoculation, and IgG was detectable 7 days after inoculation. Pasteurella haemolytica antigens were not detected in serum or plasma. A transient increase in neutrophil count was found 8 hours after inoculation, with return to baseline values by 24 hours after inoculation. Antigen was detected in lavage fluid by use of monoclonal antibodies against selected P haemolytica capsular antigen, outer membrane antigens, and leukotoxin in all inoculated calves 8 hours after inoculation. The monoclonal antibody specific for P haemolytica capsule provided the best detection of antigen. The other monoclonal antibodies detected antigen, but were less consistent.