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Abstract

Objective

To isolate Actinomyces pyogenes and A pyogenes-like (APL) organisms from the ruminal wall and ruminal contents of cattle and compare them with isolates from liver abscesses from the same animals, using ribosomal DNA restriction fragment length polymorphism analysis or ribotyping.

Procedure

Specimens of liver abscesses, ruminal walls, and ruminal contents were collected from 59 cattle at slaughter. All β-hemolytic, pinpoint colonies that were gram positive, pleomorphic rod-shaped, and catalase negative, and that hydrolyzed casein and gelatin were presumptively identified as A pyogenes and were characterized biochemically, using an identification kit. The isolates that resembled A pyogenes but fermented mannitol or raffinose, or both, were called APL organisms. Isolates from the ruminal wall and ruminal contents were compared with liver abscess isolates from the same animal by use of ribotyping.

Results

Actinomyces pyogenes and APL organisms were isolated more frequently from the ruminal wall than from ruminal contents. Ruminal isolates of A pyogenes and APL had biochemical characteristics similar to those of the isolates from liver abscesses. Among 6 sets of isolates (4 A pyogenes and 2 APL), 2 isolates from liver abscesses had ribopatterns identical to the corresponding ruminal wall isolates. Also, the APL organisms isolated from the ruminal content matched with the corresponding liver abscess isolates for both sets of specimens tested.

Conclusions

The ruminal wall may be the niche for A pyogenes and APL organisms in the rumen. The genetic similarity, on the basis of ribotyping among isolates from liver abscesses, the ruminal wall, and ruminal contents of the same animal suggests that A pyogenes and APL organisms that cause liver abscesses originate from the rumen. (Am J Vet Res 1998;59:271–276)

Free access
in American Journal of Veterinary Research

Objective

To determine whether segregated, early weaned pigs have better growth performance and different microbial flora than those of pigs raised on-site.

Design

Prospective, observational study.

Animals

Pigs from a commercial operation that were known to be infected with several common swine pathogens.

Procedure

Pigs (7 to 10 days old) were weaned and segregated from the farm of origin and compared with littermate control pigs (14 to 17 days old) that were weaned and raised on-site. Pig weight was measured and microbial flora were isolated at 14-day intervals for 84 days, beginning when the pigs were 7 to 10 days old.

Results

At 50 days of age, the segregated, early weaned pigs had a mean weight of 23.7 kg, compared with a mean weight of 12.5 kg for control pigs. Pasteurella multocida was isolated from fewer segregated, early weaned pigs than from controls. Signs of Mycoplasma hyopneumoniae infection were detected in control pigs but not in segregated early weaned pigs. Clinical, serologic, or bacteriologie signs of early postnatal vertical transmission of Actinobacillus pleuropneumonias were not detected in either group.

Clinical Implication

Vertical transmission of M hyopneumoniae was prevented by weaning pigs at 7 to 10 days of age and segregating them off-site, without the use of medication. Although medicated controls were not compared, results from this herd revealed that use of antibiotics is not the most important factor for disease control in segregated, early weaning programs. Minimizing antibiotic use in disease-control protocols reduces costs as well as removes the need for extra-label drugs. (J Am Vet Med Assoc 1996;208:711–715)

Free access
in Journal of the American Veterinary Medical Association