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Abstract

Objective—To compare the efficacy of gamithromycin with that of tulathromycin for control of undifferentiated bovine respiratory disease complex (BRDC) in feedlot calves.

Animals—2,529 weaned crossbred beef calves.

Procedures—At each of 2 feedlots, calves at risk of developing BRDC were administered a single dose of gamithromycin (6.0 mg/kg, SC; n = 1,263) or tulathromycin (2.5 mg/kg, SC; 1,266) metaphylactically. Health (BRDC morbidity, mortality, case-fatality, and retreatment rates) and performance (average daily gain, dry matter intake, and feed-to-gain ratio) outcomes were compared between treatments via classical hypothesis testing. Bioequivalence limits for gamithromycin and tulathromycin were established for outcomes for which no significant difference between treatments was detected.

Results—Mean BRDC morbidity rate (31.0%) for calves administered gamithromycin was greater than that (22.9%) for calves administered tulathromycin; otherwise, health and performance did not differ between treatments. Limits for mean differences within which gamithromycin was considered bioequivalent to tulathromycin were ± 10% for BRDC retreatment rate, ± 3.5% for BRDC mortality rate, ± 16% for case-fatality rate, ± 37 kg for final body weight, ± 0.1 kg/d for average daily gain, ± 0.3 kg/d for dry matter intake, and ± 0.7 for feed-to-gain ratio.

Conclusions and Clinical Relevance—The efficacy of gamithromycin did not differ from that of tulathromycin for all outcomes except morbidity rate; calves administered gamithromycin had a higher BRDC morbidity rate than did calves administered tulathromycin. On the basis of the bioequivalence limits established for this dataset, gamithromycin was considered equivalent to tulathromycin for the control of BRDC.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To compare the efficacy of gamithromycin with that of tulathromycin for the treatment of undifferentiated bovine respiratory disease complex (BRDC) in feedlot calves.

Animals—1,049 weaned crossbred beef calves.

Procedures—At each of 6 feedlots, newly arrived calves with BRDC were administered a single dose of gamithromycin (6.0 mg/kg, SC; n = 523) or tulathromycin (2.5 mg/kg, SC; 526). Case-fatality and BRDC retreatment rates during the first 120 days after treatment, final body weight, and average daily gain (ADG), were compared between treatments. At 2 feedlots, calves were assigned clinical scores for 10 days after treatment to determine recovery rates for each treatment. Bioequivalence limits for gamithromycin and tulathromycin were calculated for outcomes for which there was no significant difference between treatments.

Results—Mean BRDC retreatment rate (17.7%) for calves administered gamithromycin was greater than that (9.0%) for calves administered tulathromycin. Mean case-fatality rate, final body weight, ADG, and clinical score 10 days after treatment did not differ significantly between treatments. Limits for mean differences within which gamithromycin was bioequivalent to tulathromycin were ± 2.4% for case-fatality rate, ± 13 kg for final body weight, and ± 0.1 kg/d for ADG.

Conclusions and Clinical Relevance—Calves administered gamithromycin had a higher BRDC retreatment rate than did calves administered tulathromycin; otherwise, the clinical efficacy did not differ between the 2 treatments for the treatment of BRDC in feedlot calves.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To determine the biocontainment, biosecurity, and security practices at beef feedyards in the Central Plains of the United States.

Design—Survey.

Sample Population—Managers of feedyards in Colorado, Kansas, Nebraska, Oklahoma, and Texas that feed beef cattle for finish before slaughter; feedyards had to have an active concentrated animal feeding operation permit with a 1-time capacity of ≥ 1,000 cattle.

Procedures—A voluntary survey of feedyard personnel was conducted. Identified feedyard personnel were interviewed and responses regarding facility design, security, employees, disease preparedness, feedstuffs, hospital or treatment systems, sanitation, cattle sources, handling of sick cattle, and disposal of carcasses were collected in a database questionnaire.

Results—The survey was conducted for 106 feedyards with a 1-time capacity that ranged from 1,300 to 125,000 cattle. Feedyards in general did not have high implementation of biocontainment, biosecurity, or security practices. Smaller feedyards were, in general, less likely to use good practices than were larger feedyards.

Conclusions and Clinical Relevance—Results of the survey provided standard practices for biocontainment, biosecurity, and security in feedyards located in Central Plains states. Information gained from the survey results can be used by consulting veterinarians and feedyard managers as a basis for discussion and to target training efforts.

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in Journal of the American Veterinary Medical Association