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  • Author or Editor: Gary R. McArthur x
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Abstract

OBJECTIVE

To determine the pharmacokinetics of sodium iodide (NaI) following oral administration to preweaned dairy calves, and to assess the efficacy of NaI for prevention of bovine respiratory disease (BRD) in preweaned calves at a commercial calf-raising facility.

ANIMALS

434 healthy preweaned dairy calves.

PROCEDURES

In the first of 2 experimental trials, each of 7 calves received NaI (20 mg/kg, PO) once. Blood and nasal fluid samples were collected at predetermined times before (baseline) and for 72 hours after NaI administration for determination of iodine concentrations. Pharmacokinetic parameters were determined by noncompartmental analysis. In the second trial, 427 calves at a calf-raising facility were randomly assigned to receive NaI (20 mg/kg, PO, 2 doses 72 hours apart; n = 211) or serve as untreated controls (216). Health outcomes were compared between the 2 groups.

RESULTS

For all 7 calves in the pharmacokinetic trial, the iodine concentration in both serum and nasal fluid samples was significantly increased from the baseline concentration and exceeded the presumed therapeutic iodine concentration (6.35 μg/mL) throughout the sampling period. In the on-farm trial, the odds of being treated for BRD before weaning for NaI-treated calves were twice those for control calves (OR, 2.04; 95% CI, 1.38 to 3.00).

CONCLUSIONS AND CLINICAL RELEVANCE

Results suggested that, although oral administration of NaI (20 mg/kg) to preweaned dairy calves achieved iodine concentrations presumed to be effective in both serum and nasal fluid, it was not effective for prevention of BRD in preweaned calves at a commercial calf-raising facility.

Full access
in American Journal of Veterinary Research

Abstract

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)

Full access
in American Journal of Veterinary Research