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  • Author or Editor: W. A. Arden x
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SUMMARY

Blood, feces, and nasal swabs specimens were collected 12 to 24 hours after birth and then 3 times/week (blood only once per week) from one group of 10 calves until they were 10 weeks old and from a second group of 10 calves until they were 10 to 20 weeks old. Colostrum was collected from all calves’ dams and tears from 5 randomly selected calves in the first group. All fecal and nasal specimens were assayed for bovine coronavirus (bcv) antigens by elisa. Nasal epithelial cells were examined for bcv antigens by direct immunofluorescence. Isotype antibody titers to bcv in all samples from 5 calves in group 1 were evaluated by elisa. Zinc sulfate turbidity (zst) values were determined on the first serum samples taken from all calves in group 1. To determine whether any correlation existed between zst values, isotype antibody titers to bcv (12 to 24 hours after birth), number of respiratory sick days, number of enteric sick days, or days to first shedding of virus, a Spearman rank order correlation coefficient was done.

Bovine coronavirus respiratory tract and enteric tract infections were common on this farm. Most initial infections developed when calves were 1 to 3 weeks old; however, there were also multiple incidences of shedding of viral antigens or seroconversions at later times during the study. Persistence of infection or reinfection of the upper respiratory tract with bcv was common.

Colostral antibody titers to bcv (IgG1) were in all cows at moderate amounts; however, calf serum antibody titers and zst values (12 to 24 hours after birth) were highly variable. Significant correlations were found between zst values and bcv IgG1, IgG2, and IgA serum antibody titers (12 to 24 hours after birth); and number of respiratory sick days and zst values, IgG1, IgG2, and IgA serum antibody titers (12 to 24 hours after birth). All calves in group 1 had serum antibody IgM titer increases to bcv when they were 1 to 2 weeks old and many had subsequent IgA, IgG2, and IgG1 serum antibody titer increases in the first 4 weeks. Six calves had a second serum antibody titer increase with IgM or IgA isotypes when they were 5 to 9 weeks old. In the second group, IgM, IgA, and IgG serum antibody titers were increased > fourfold in 6 of 9, 8 of 9, and 5 of 9 calves, respectively. Most calves had passive IgG1 bcv antibodies in their nasal secretions or tears when they were 1 week old and all calves had at least one transient increase in active IgM antibody titers followed by a sharp and persistent increase in IgA titers. All calves had bcv antibodies (IgG1, IgA, or IgM) in their feces when they were 1 week old and at least one transient increase in fecal IgM (4 of 5 calves) or IgA (3 of 5 calves) antibody titers in the 9-week period.

Free access
in American Journal of Veterinary Research

Summary

Effects of 1 hour of colonic volvulus and 3 hours of reperfusion on concentrations of thromboxane (txb 2) and prostacyclin (6-keto-PGF) in portal, pulmonary arterial, and jugular blood were determined by radioimmunoassay to assess the site of production and clearance of these eicosanoids from the circulation in 5 anesthetized ponies. Colonic volvulus had no significant effect on mean arterial pressure or txb 2 concentrations, but significantly (P < 0.05) increased 6-keto-PGF concentrations in all blood samples. Immediately after colonic reperfusion, all eicosanoid concentrations were significantly (P < 0.05) increased. Then, txb 2 returned to baseline values, whereas 6-keto-PGF concentrations remained significantly (P < 0.05) high for the remainder of the study. Eicosanoid concentrations were significantly (P < 0.05) greater in portal blood than in pulmonary arterial and jugular blood samples at all periods. This suggests that the splanchnic circulation is the primary site of eicosanoid production during and after colonic volvulus and the liver appears to provide most of the circulatory clearance of thromboxane and prostacyclin.

Free access
in American Journal of Veterinary Research

Abstract

Objective—To determine efficacy of intranasal vaccination of rabbits with Pasteurella multocida A:3 outer membrane proteins (OMP) expressing iron-regulated OMP (IROMP) in conferring protection against experimental challenge exposure.

Animals—52 male New Zealand White rabbits.

Procedure— Rabbits were vaccinated intranasally on days 0, 7, and 14; some vaccines included cholera toxin (CT) as an adjuvant. Concentrations of intranasal IgA and serum IgG antibodies against P multocida OMP were determined. In experiment A, rabbits were vaccinated with either phospate-buffered saline solution (PBSS), PBSS-CT, OMP-CT, or IROMP-CT, challenge-exposed intranasally on day 16, and euthanatized and necropsied on day 28. Rabbits were also vaccinated with OMP or IROMP without CT and were not challenge-exposed. In experiment B, rabbits were vaccinated with PBSS, PBSS-CT, IROMP, or IROMP-CT. On day 17, rabbits were challenge-exposed intranasally .Nasal bacteria and antibodies were determined on day 24.

Results—In experiment A, OMP-CT vaccination stimulated mucosal and systemic antibody responses to the bacterium and enhanced resistance against challenge exposure. Intranasal bacterial counts were not significantly reduced. Vaccination with IROMP-CT stimulated mucosal and systemic antibodies, enhanced resistance to challenge exposure, and significantly reduced nasal bacterial counts. In experiment B, natural infection was detected in several rabbits at challenge exposure; however, IROMP-CT-vaccinated rabbits had significantly higher serum and nasal antibody responses, compared with other rabbitsIROMP-CT-vaccinated rabbits had significantly lower nasal bacterial counts compared to control rabbits.

Conclusions and Clinical Relevance—Intranasal vaccination of rabbits with P multocida outer membranes containing IROMP and CT stimulated immunity against experimental pneumonic pasteurellosis. (Am J Vet Res 2001;62:697–703)

Full access
in American Journal of Veterinary Research