Evaluation of vaccination with a commercial subunit vaccine on shedding of Salmonella enterica in subclinically infected dairy cows.
OBJECTIVE
To estimate the efficacy of a commercially available Salmonella enterica subunit vaccine on the subclinical shedding of S enterica in dairy cattle.


METHODS
Randomized, controlled trial.


METHODS
175 mature cows on 2 dairy farms with a history of S enterica infection.


METHODS
25% of the mature cows from each herd were systematically randomized to receive an S enterica subunit vaccine following label guidelines. The remaining 75% of cows in each herd served as nonvaccinated controls. Fecal samples were collected from all cows at the time of initial vaccination (day 0), booster vaccination (day 14), 2 weeks following the booster vaccination (day 28), and 10 weeks following the start of the trial (day 70). All samples were processed on the day of collection and cultured for S enterica.


RESULTS
651 fecal samples were obtained over the entire study period. Salmonella enterica was recovered from 46 (7.1%) of the samples. Shedding of S enterica was similar for vaccinated and nonvaccinated control cows on each of the collection dates.


CONCLUSIONS
The study revealed no evidence that extralabel vaccination with a commercial subunit S enterica vaccine reduced shedding of S enterica in subclinically infected dairy cows in these herds.
Heider
Luke C
LC
Department of Veterinary Preventative Medicine, College of Veterinary Medicine, The Ohio State University, Columbus, OH 43210, USA.
Meiring
Richard W
RW
Hoet
Armando E
AE
Gebreyes
Wondwossen A
WA
Funk
Julie A
JA
Wittum
Thomas E
TE
D000822:Animal Husbandry / Q000379:methods; D000818:Animals; D002417:Cattle; D002418:Cattle Diseases / Q000517:prevention & control*; D015169:Colony Count, Microbial / Q000662:veterinary; D005243:Feces / Q000382:microbiology*; D005260:Female; D012481:Salmonella Infections, Animal / Q000517:prevention & control*; D022562:Salmonella Vaccines / Q000008:administration & dosage*; D019779:Salmonella enterica / Q000276:immunology* / Q000302:isolation & purification; D022223:Vaccines, Subunit
D022562:Salmonella Vaccines; D022223:Vaccines, Subunit