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  • Author or Editor: Monica M. Ontiveros x
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Objective—To evaluate therapeutic efficacy of a high extralabel dose of ceftiofur for treatment of experimental salmonellosis in neonatal calves.

Animals—Forty-two 1- to 4-day-old Holstein bull calves.

Procedure—36 calves were orally challenged with Salmonella enteritica serovar Typhimurium (6.5 × 108 colony-forming units). Six additional calves were retained as nonmedicated nonchallenged control calves. Four days following Salmonella challenge, surviving calves were randomly allocated to ceftiofurtreated (5 mg/kg, IM, q 24 h) or nonmedicated control groups. Calves assigned to the treated group were medicated daily for 5 days starting on day 4 after challenge. Calves were monitored for 18 days following Salmonella challenge. Outcome assessments included clinical parameters (attitude, appetite, fecal characteristics, and rectal temperature), mortality rate, and quantitative Salmonella culture of fecal samples, mesenteric lymph nodes, and cecal contents.

Results—Ceftiofur treatment was associated with a significant decrease in rectal temperature and diarrhea. Three of 15 medicated calves and 4 of 14 nonmedicated calves died or were euthanatized between days 4 and 18. A significant decrease in fecal shedding of Salmonella organisms was observed in treated calves, compared with non-medicated calves. Salmonella organisms were isolated from all 10 nonmedicated calves at necropsy, whereas no Salmonella organisms were isolated from 5 of 12 medicated calves.

Conclusions and Clinical Relevance—Treatment of salmonellosis in neonatal calves with a high extralabel dose of ceftiofur (5 mg/kg, IM, q 24 h) promotes animal welfare, reduces fecal shedding of Salmonella organisms, and may promote clearance of Salmonella infections when plasma ceftiofur concentrations are maintained above minimal inhibitory concentrations. (Am J Vet Res 2003;64:918–925)

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in American Journal of Veterinary Research


Objective—To compare the efficacy of a Salmonella bacterin and a modified live Salmonella ser. Choleraesuis vaccine on a commercial dairy.

Animals—450 cows in late gestation and 80 calves.

Procedure—Group-1 cows (n = 150) were vaccinated once with a modified live S Choleraesuis (serogroup C1) strain 54 (SC54) vaccine, group-2 cows (150) were vaccinated on enrollment and 30 days later with a Salmonella ser. Montevideo (serogroup C1) bacterin, and group-3 cows (150) served as unvaccinated controls. One gallon of colostrum harvested from the first 80 cows to calve was fed to each calf. Outcome assessments included fecal shedding of Salmonella spp for the first 10 days after parturition (cows) or birth (calves), milk production, involuntary culling rate, mastitis incidence, antimicrobial use, and mortality rate.

Results—Salmonellae were isolated from 306 of 309 (99%) cows and 64 of 74 (86.5%) calves. Shedding frequency was less in SC54-vaccinated cows and calves that received colostrum from those cows, compared with the other groups, and vaccination was specifically associated with less shedding of serogroup C1 salmonellae. Production data were similar among groups.

Conclusions and Clinical Relevance—Vaccination of pregnant cows with an autogenous Salmonella bacterin had no effect on fecal shedding of salmonellae, whereas vaccination with a modified live S Choleraesuis vaccine reduced the frequency of fecal shedding of serogroup C1 salmonellae during the peripartum period. A commercial S Choleraesuis vaccine licensed for use in swine may be more efficacious than autogenous Salmonella bacterins on dairies infected with serogroup C1 salmonellae. (Am J Vet Res 2001;62:1897–1902)

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in American Journal of Veterinary Research