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Abstract

Objective

To determine effects of tylosin on ruminal concentrations of Fusobacterium necrophorum and fermentation products in cattle during rapid adaptation to a high-concentrate diet.

Animals

6 steers fitted with ruminal cannulas.

Procedure

Steers were assigned randomly to 2 treatment groups and switched from a 0 to an 85% concentrate diet during a 4-day period. Cattle received this diet, with or without tylosin (90 mg/steer/d), for 4 weeks. Samples of ruminal contents were collected daily beginning 2 days before the treatment protocol and in the first week of concentrate feeding. Four subsequent samples were collected at weekly intervals. Concentration of F necrophorum in samples was determined, using the most-probable-number technique. Ruminal pH and concentrations of volatile fatty acids (VFA), lactate, and ammonia also were determined. All steers received both treatments separated by 4 weeks (cross-over design), during which time they were fed alfalfa hay only.

Results

In control steers, concentration of F necrophorum increased in response to the high-concentrate diet. Tylosin-fed steers had lower concentrations of F necrophorum than control steers at all times during concentrate feeding. However, ruminal pH and concentrations of lactate, VFA, and ammonia did not differ between treatment groups.

Conclusions and Clinical Relevance

Tylosin caused a significant reduction in ruminal concentrations of F necrophorum during rapid adaptation to a high-concentrate diet but had no effect on fermentation products. The reduction in ruminal concentration of F necrophorum helps explain the reduction in prevalence of hepatic abscesses reported in tylosin-fed feedlot cattle. (Am J Vet Res 1999;60:1061-1065)

Free access
in American Journal of Veterinary Research

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

Abstract

CASE DESCRIPTION A 20-year-old female south-central black rhinoceros (Diceros bicornis minor) was evaluated because of an acute onset of CNS deficits.

CLINICAL FINDINGS The rhinoceros had no history of illness. Clinical signs included acute lethargy, ataxia, and decreased appetite. Hematologic abnormalities included leukocytosis with neutrophilia and a profound left shift. Results of serum biochemical analysis revealed hypophosphatemia but no other abnormalities. Results of a quantitative PCR assay for West Nile virus and an assay for anti–Neosporum caninum antibodies in serum were negative; the patient was seropositive for multiple Leptospira serovars.

TREATMENT AND OUTCOME Antimicrobials and anti-inflammatory agents were administered, but the condition of the rhinoceros worsened overnight; despite treatment with additional anti-inflammatory and antimicrobial agents, IV fluids, and thiamine, it became obtunded and died of respiratory arrest ≤ 24 hours later. Necropsy revealed severe, diffuse, suppurative, and histiocytic meningo-encephalomyelitis involving the cerebrum, cerebellum, and spinal cord. Amebic trophozoites were observed on histologic examination of affected tissue. Infection with Naegleria fowleri was confirmed by results of immuno-histochemical analysis and a multiplex real-time PCR assay.

CLINICAL RELEVANCE Findings suggested that south-central black rhinoceros are susceptible to the free-living ameba N fowleri. Ameba-induced meningoencephalomyelitis should be considered as a differential diagnosis for rhinoceros that have an acute onset of neurologic signs. Diagnosis of N fowleri infection in an animal has a profound public health impact because of potential human exposure from the environment and the high fatality rate in people with N fowleri infection.

Full access
in Journal of the American Veterinary Medical Association

Abstract

Objective—To determine percentages of domestic cats and dogs vaccinated against rabies, identify barriers to vaccination, and assess knowledge about rabies in a semirural New Mexico community after a skunk rabies outbreak.

Design—Cross-sectional, door-to-door, bilingual, community-based participatory survey.

Sample—366 residential properties in Eddy County, NM.

Procedures—The New Mexico Department of Health and CDC administered surveys and analyzed data.

Results—Individuals at 247 of the 366 residential properties participated in the survey. One hundred eighty of the 247 (73%) households owned a dog (n = 292) or cat (163). Cats were more likely than dogs to not have an up-to-date rabies vaccination status (prevalence ratio, 3.2; 95% confidence interval, 2.3 to 4.4). Cost and time or scheduling were the most frequently identified barriers to vaccination. One hundred sixty (65%) respondents did not know livestock can transmit rabies, 78 (32%) did not know rabies is fatal, and 89 (36%) did not know a bat scratching a person can be an exposure. Only 187 (76%) respondents indicated they would contact animal control if they saw a sick skunk, and only 166 (67%) indicated they would contact animal control if bitten by a dog they did not own.

Conclusions and Clinical Relevance—Findings indicated that rabies vaccination prevalence among pet dogs and cats was low, despite the fact that the region had experienced a skunk rabies outbreak during the previous 2 years. In addition, substantial percentages of respondents did not have correct knowledge of rabies or rabies exposure.

Full access
in Journal of the American Veterinary Medical Association