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  • Author or Editor: Lynda C. Kelley x
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SUMMARY

Icterus condemnations compose a substantial proportion (41%) of total condemnations of bob veal, the class of veal composed of calves < 3 weeks old and weighing up to 68 kg. At postmortem examination, bob veal condemned because of icterus have generalized yellow discoloration of tissues, which is commonly associated with large, yellow liver (fatty liver), and a paucity of other gross pathologic changes. To establish that the generalized yellow discoloration was attributable to high tissue bilirubin concentrations and to examine the underlying mechanism(s) that might be responsible, blood samples and tissue specimens were obtained from clinically normal and icteric bob veal calves at slaughter. For comparison, blood samples were collected from clinically normal, 1- to 5-day-old Holstein calves being raised on local dairy farms. Hematologic and serum biochemical analyses were obtained for the 3 groups of calves (normal local, normal slaughter, and icteric slaughter), and tissues of slaughter calves were examined for histologic evidence of inflammatory or degenerative changes. Mean ± sd total bilirubin concentration and creatine kinase (ck) activity in icteric bob veal (3.3 ± 0.8 mg/dl; 869 ± 788 U/L), normal bob veal (1.4 ± 0.7 mg/dl; 486 ± 890 U/L), and normal local calves (0.5 ± 0.2 mg/dl; 156 ± 158 U/L) were significantly different. When data for both normal and icteric bob veal calf groups were combined for analysis, total bilirubin concentration regressed significantly on hepatic lipid scores (P = 0.00003) and ck activity (P = 0.00049). Colostrum consumption was determined by measuring serum total protein concentration and serum γ-glutamyltransferase activity. Bob veal calves that had not consumed colostrum had significantly higher total bilirubin (P = 0.00005) and ck (P = 0.0008) values. It was concluded that normal and icteric bob veal calves have significant increase in total bilirubin concentration, and icterus of bob veal calves is secondary to unconjugated hyperbilirubinemia. Lack of colostrum consumption was strongly correlated with icterus in bob veal calves.

Free access
in American Journal of Veterinary Research

Summary

Campylobacter jejuni A74/O and A74/C are congenic strains. An oral dose of 105 organisms of strain A74/C colonizes chicken intestines. Strain A74/O, from which A74/C is derived, does not colonize the chicken intestines with an oral dose of 105 organisms. In this study, the congenic bacteria were compared to identify possible colonization mechanisms. Differences were not observed in plasmid content or by HindIII, Pst I, Acc I, HincII, Ava I, Ava II, Xba I, and BamHI restriction enzyme digestion of total dna. Transmission electron microscopy of negatively stained samples revealed no differences between the strains. Sections of cecal tissue from nonfed day-of-hatch chicks were cultured with each strain for 2 hours and then examined by light and electron microscopy. Both strains caused necrosis of villus epithelial cells. Immunofluorescent or silver staining revealed strain A74/C located deep in numerous epithelial crypts, but strain A74/O only was present in one sample mixed with sloughed necrotic cells. Similarly, organisms were detected by transmission electron microscopy deep in crypts in tissues cultured with A74/C, but not A74/O. Cells of A74/C detected in crypts did not appear to associate with epithelial cells. The strains did not differ in chemotactic behavior to mucin or fucose.

Free access
in American Journal of Veterinary Research