Twenty-six clinically normal colostrum-fed dairy calves were allotted to 5 groups. Calves of groups 1 and 2 served as nonvaccinated controls and were challenge-exposed with variable numbers of organisms. Group-3 calves were vaccinated SC with a modified Salmonella typhimurium bacterin. The bacterin was composed of killed acid-hydrolyzed S typhimurium G30/C21 (Re-mutant) whole cells coated with alkali-hydrolyzed S typhimurium LT-2 lipopolysaccharide, as antigen, and monophosphoryl lipid A, as adjuvant. Calves of groups 4 and 5 were vaccinated with a 2% mineral oil-in-water emulsion containing lipopolysaccharide as antigen and monophosphoryl lipid A and trehalose 6-6'-dimycolate as adjuvants. Calves of groups 3-5 were vaccinated at 2 weeks of age and again at 4 or 6 weeks of age. Adverse reactions were not observed after vaccination. Calves were challenge-exposed orally at 6 or 8 weeks of age with 1.5 X 10(11) (groups 1 and 4), or 3.0 X 10(11) (groups 2, 3, and 5) colony-forming units of S typhimurium UCD 108-11. Mortality after challenge exposure was 2 of 5 group-1 calves; 4 of 5 group-2 calves; 5 of 6 group-3 calves; 1 of 5 group-4 calves; and 4 of 5 group-5 calves. Statistical difference between calves of similarly challenge-exposed groups was not evident, indicating failure of either vaccine to protect calves of this age from oral challenge exposure with virulent S typhimurium.

Blood culture and serologic testing were used to study the prevalence of Trypanosoma cruzi infection in a group of 85 dogs from southern Louisiana rural environment. These dogs were known to have been in contact with wild mammalian hosts of the hemoflagellate. Results were compared with blood culture and serologic test results in 103 dogs from a rural environment and with limited known wild mammalian T cruzi host contact. Serologic test results for the 188 dogs from the rural environment were compared with results for 176 dogs from an urban animal shelter and for 100 household pet dogs from an urban southern Louisiana environment. Blood culture was not performed on urban dogs. Culture results were negative in all dogs from rural environments. Serologic evidence of infection was obtained for 4 of the 85 (4.7%) dogs of rural environment with known host contact. Of 176 dogs from the animal shelter, 4 (2.3%) had high antibody titer to T cruzi, and 11 others had low titer (< 2 adjusted ELISA units [aEU]). Two and 4 dogs of the housed urban and rural groups, respectively, had antibody titer to T cruzi that was < 2 aEU. Results indicate that prevalence for exposure to T cruzi antigen is higher in dogs with high potential contact with the vector and wild mammalian hosts of T cruzi, whether they are from rural or urban environment. Furthermore, results indicate that similar studies on high-risk human populations may be indicated.

To evaluate underlying causes of calcium oxalate urolithiasis, 24-hour excretion of urine metabolites was measured in 6 Miniature Schnauzers that formed calcium oxalate (CaOx) uroliths during periods when they were fed a standard diet and during periods when food was withheld. Serum concentrations of parathyroid hormone and 1,25-dihydroxyvitamin D also were evaluated. Serum calcium concentrations were normal in all 6 affected Miniature Schnauzers; however, during diet consumption, mean 24-hour urinary excretion of calcium was significantly (P = 0.025) higher than calcium excretion when food was withheld. In 1 dog, urinary calcium excretion was lower during the period of food consumption, compared with the period when food was withheld. Compared with clinically normal Beagles, Miniature Schnauzers that formed CaOx uroliths excreted significantly greater quantities of calcium when food was consumed (P = 0.0004) and when food was withheld (P = 0.001). Miniature Schnauzers that formed CaOx uroliths excreted significantly less oxalate than clinically normal Beagles during fed (P = 0.028) and nonfed (P = 0.004) conditions. Affected Miniature Schnauzers also excreted abnormally high quantities of uric acid. Excretion of citrate was not different between Miniature Schnauzers with CaOx urolithiasis and clinically normal Beagles. In 5 of 6 Miniature Schnauzers with CaOx urolithiasis, concentrations of serum parathyroid hormone were similar to values from age- and gender-matched Miniature Schnauzers without uroliths. The concentration of serum parathyroid hormone in 1 dog was > 4 times the mean concentration of clinically normal Miniature Schnauzers. Mean serum concentrations of 1,25-dihydroxyvitamin D in Miniature Schnauzers with calcium oxalate urolithiasis were similar to concentrations of clinically normal Miniature Schnauzers.

Conventionally raised Chinese Meishan and European Large White pigs were intragastrically challenge exposed with 2. 1 X 10(10) enterotoxigenic Escherichia coli strains bearing colonization factor K88, 987P, F41, or F41 plus K99. In response to challenge exposure with the K88-positive (K88+) organisms, 96% of Large White pigs died within 48 hours, whereas none of the Meishan pigs died. Both breeds of pigs had similar susceptibility to strains bearing 987P or F41. Lastly, Meishan pigs were found to be more susceptible than Large White pigs to a strain expressing K99 and F41. In pigs with diarrhea, challenge-exposure strains intensively colonized the jejunum (10(8) to 10(10) bacteria/g of tissue) and, to less extent, the duodenum (except K88+ strain, which comprised 10(8)/g). In most cases, jejunal concentrations of the challenge-exposure strains were substantially lower in pigs that did not have diarrhea. Half the resistant Meishan pigs eliminated the K88+ strain from the intestines. Colostral antibody titer that agglutinated challenge-exposure strains did not differ between Meishan and Large White gilts. Results indicate that resistance of pigs to the K88+ strain did not extend to enterotoxigenic strains bearing other well-known factors. They indicate, in addition, that genetic resistance to K88+ strains described in pigs in Europe may exist in pigs in China.

Log-linear methodology was used to examine relations among caprine arthritis-encephalitis virus (CAEV) seroreactivity and host/management factors in a cross-sectional study of 2,826 goats on 13 California dairies. The CAEV serologic status was associated with age and feeding method (pasteurized/unpasteurized milk), but not with breed. Data from a prevalence survey of 321 goats from 2 additional dairies demonstrated very good fit of the selected log-linear model (P = 1.00), indicating that the model was very appropriate to describe the relations. Odds of seropositivity and odds ratios were generated by use of a logit model derived from the log-linear model. Goats raised by the unpasteurized feeding method were estimated to have been 3.3 times more likely to be CAEV-seropositive than goats fed by the pasteurized method, when adjusted for the effects of age. Goats aged 2, 3, 4, and 5 or greater years were estimated to have been 1.7, 2.6, 4.5, and 5.7 times, respectively, more likely to be CAEV-seropositive than were yearling goats when ratios were adjusted for pasteurization status. Breed, gender, and herd of origin were not associated with CAEV seroreactivity when the effects of other factors were considered. Estimated odds of CAEV seroreactivity and the associated odds ratios for combinations of factor levels are reported. In this study, the magnitude and direction of the associations among CAEV serologic status, age, and pasteurized feeding methods were demonstrated.

The purpose of this study was to evaluate the effect of withdrawal of lactose from the diet for 72 hours on lactase activity in the jejunal mucosa of conventionally raised calves. The descending portion of the duodenum of six Holstein calves < 24 hours old was cannulated. The calves were fed milk except on days 5, 6 and 7 when they were given the same volume of an electrolyte solution. Sequential biopsy specimens of the proximal jejunal mucosa were obtained for three weeks and the lactase activity determined. Lactase activity was highest on day 1 and a trend toward decreased lactase activity from birth until three weeks was observed. Mean lactase activity was significantly (p < 0.05) higher for days 1, and 3 compared to days 9, 13 and 17. The withdrawal of milk and replacement by an electrolyte solution during three days had no significant effect on jejunal mucosal lactase activity in neonatal calves.

Larkspur poisoning is a major cause of acute death of cattle on mountain and high plains rangelands of western United States. A nonlethal method to quantify dose response in cattle is needed to better estimate the toxicity of larkspur plants and the response of cattle to larkspur poisoning and to provide a basis for reference during studies. A numerical system of rating the clinical signs of larkspur poisoning was developed and used to describe the response of 10 Hereford cows given a repeated single daily dose of larkspur (Delphinium occidentale X barbeyi) by gavage. Larkspur poisoning resulted from a short-term cumulative effect, and a statistically significant increase in score was essentially maximal by 4 days. At the dose given, this effect did not persist for more than 4 days after cessation of dosing. Poisoning was most severe between 5 and 9 hours after dosing. Early signs of poisoning can be subtle and sometimes brief. The effect of larkspur poisoning can be exacerbated temporarily by exertion. Therefore, cattle could probably repeatedly consume an otherwise toxic daily dose, without manifesting marked signs of poisoning, if consumption decreased to a sufficient degree intermittently at 2- to 4-day intervals.

Sheep had viremias that were first detected on day 3 (+/- 1) after infection with several strains of bluetongue virus (BTV) representing United States serotypes 10, 11, 13, and 17. Diphasic peaks of infectivity were attained on days 6 and 10 (+/- 2). Interferon (IFN) was first detected in serum samples on day 5 (+/- 1), and reached greatest concentrations on day 6 (+/- 2), which coincided with the first viremic peak; IFN concentrations then decreased toward zero by day 10 (+/- 2). Interferon peak concentrations induced approximately a 90% decrease in virus titer. The decrease in IFN concentrations by day 9 (+/- 2) corresponded with the second viremic peak on day 10 (+/- 2). Onset of the decrease in detectable concentrations of virus after the second peak of viremia corresponded to the initial detection of serum antibody to BTV by day 10 (+/- 2). Virus titer decreased and antibody production increased until approximately days 21 to 28, when the titers plateaued and virus was not detected. Febrile responses peaked on day 7 (+/- 1) during the peak viremic period. The WBC count was depressed at the time the virus titer increased, but returned to normal values while the sheep were still viremic. Diphasic viremias in BTV-infected sheep were attributed to induction of high concentrations of IFN concurrent with the first virus titer peak, followed by production of antibody to specific BTV strains and a subsequent reduction in viremia at the second virus titer peak.

Enzyme-linked immunosorbent assay screening of antibody produced against aflatoxin was accomplished by a new and simple procedure. To demonstrate the new indirect ELISA technique used, antibody against aflatoxin M1 was produced in female BALB/CJ mice by immunization with an aflatoxin M1-bovine serum albumin conjugate. Instead of coating test-plate wells with purified antibody (direct ELISA) or synthesizing a second protein-aflatoxin conjugate (aflatoxin M1-poly-L-lysine) to coat test-plate wells, wells were coated with the readily available aflatoxin M1-bovine serum albumin and aflatoxin B1-bovine vine serum albumin. This method, applicable for any aflatoxin conjugated by the common cyclopentano-carboxymethoxyl-oxime technique, eliminates the more time-consuming and technically difficult portions of earlier direct and indirect ELISA. The new technique can be valuable in continued efforts toward development of new and improved immunoassays against aflatoxin metabolites.

A comparison of immune variables following lung sensitization with live Pasteurella haemolytica serotype 1 (Ph1)-impregnated agar beads was done in 2 separate trials. The Ph1 immune variables studied were blood bactericidal activity, serum bacteriolysis, total classical complement, and indirect hemagglutination antibody. Each trial had 16 male weanling goats: 6 controls and 10 principals. In trial 1, each goat was surgically catheterized through the trachea, then the material was deposited in a bronchus. The controls received only agar beads and the principals received agar beads impregnated with live Ph1. These goats were studied for 32 days, euthanatized, and necropsied. In trial 2, the controls were each transthoracically injected with agar beads into the left lung and the principals were similarly injected with agar beads impregnated with live Ph1. These goats were studied for 35 days, then challenge exposed transthoracically by injection of Ph1 in saline solution (1.2 X 10(7) CFU/ml) into the right lung. Four days later, they were euthanatized and necropsied. The volume of lung consolidated tissue was an excellent measure of Ph1 immunity. Principal goats generated solid protective immunity to subsequent challenge exposure because minimal or no lung consolidation was observed, whereas large volumes of lung consolidation were seen in the controls. The principal goats in trial 1 gave a weak serum indirect hemagglutination Ph1 antibody response, which was attributed to the bronchial method of depositing the Ph1. The corresponding response of the control group remained negative. The Ph1 agar beads (1 X 10(6) CFU in 0.5 ml) protected the bacteria from immediate phagocytosis and lysis as indicated by the induced pneumonic deaths of 2 principals 5 days later. Also, live Ph1 were isolated on day 32 during necropsy of respiratory tracts of 3 principals. At necropsy, no Ph1 isolates were found in the controls. Bacteriolytic activity was not induced against Ph1 in either control or principal groups in this trial. the study, but antibody titers of the principals increased to a geometric mean of 1:250 seven days after lung injection (1 X 10(5) CFU in 0.5 ml). Serum bacteriolytic titers on day 0 indicated that both principals and controls could be subgrouped to high or low subgroups on the basis of their bacteriolytic activity. The bacteriolytic activities of the controls remained unchanged during the experiment, and neither control subgroup was protected from Ph1 challenge exposure. Bacteriolytic activities of the high and low principal subgroups responded differently to Ph1 agar bead lung injection, but both principal subgroups were protected from lung challenge exposure. The low principal subgroup generated high titers of indirect hemagglutination Ph1 antibody, whereas, the high principal subgroup generated lower antibody titers. Total complement, serum bacteriolytic, and blood bactericidal profiles were similar in the principal group with high bacteriolytic activity. The immune factors that protected 2 principal subgroups did not appear to be associated with Ph1 serum bacteriolysis.