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  • Author or Editor: Darwin R. Yoder x
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Objective—To measure the reduction in fecal nematode egg counts and productivity impact of treatment of yearling steers with doramectin at entry into the feedlot, compared with control steers treated only with fenthion.

Animals—6,096 crossbred yearling steers with a mean (± SD) body weight of 377.0 (± 37) kg.

Procedure—Steers were implanted with zeranol and alternately separated to fill each of 24 pens. Groups of steers within 12 matched pairs of pens were randomly allocated to treatment with doramectin or no treatment with doramectin for internal nematodes. Fecal samples were collected from approximately every twentieth steer from each pen at day 0 and at reimplant (approx day 60). Each steer was weighed on day 0 and at reimplant and then mean body weights of steers per pen were determined at 120 to140 days after trial initiation.

Results—Treatment steers had a significantly lower fecal egg count at reimplant than control steers. Treatment steers had a significantly greater mean daily gain during the study, significantly greater feed consumption, significantly lower feed-to-gain ratio, and significantly better quality carcass grades at slaughter.

Conclusion and Clinical Relevance—Under the conditions of our trial, there was a significant fecal egg count reduction response to doramectin treatment, which resulted in significantly improved productivity. Results of economic analysis of return on investment indicated that even with low egg counts in heavy body weight cattle, nematode egg count reduction with doramectin significantly improved returns. (Am J Vet Res 2001;62:622–624)

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in American Journal of Veterinary Research


Objective—To determine whether beef herds could increase profitability by reducing production cost per 100 lb (hundredweight [CWT]; ie, 45.4 kg) of calf through implementation of advice from teams of veterinarians and county extension agents supported by university specialists.

Design—Longitudinal study.

Sample Population—6 commercial cow-calf herds comprising 1,927 cows.

Procedure—Teams of veterinarians and county extension agents provided advice on 25 profitable ranch management practices to herd owners for 3 years. Use of each practice in herds was measured on a scale of 1 to 5 for baseline year 1999. Similar measurements were made at the end of each year for comparison with baseline values. Outcomes were measured by standardized performance analysis.

Results—Mean weaning weight of calves per exposed cow of the 6 herds increased significantly from 1999 (2000, 26.8 kg [59 lb; 17%]; 2001, 49.1 kg [108 lb; 31%]; and 2002, 43.2 kg [95 lb; 27%]). Mean cost per CWT of calf decreased significantly from the 1999 value (2000, −$20.04 [−18%]; 2001, −$33.40 [−29%]; and 2002, −$22.52 [−20%]). Additional profits for the 6 herds were $54,407 in 2000, $135,695 in 2001, and $116,089 in 2002 (3-year total of $306,191). Mean increase in management score of herds was positively correlated with increase in net income and accounted for > 60% of increased profits.

Conclusions and Clinical Relevance—Profitability of beef cow-calf operations can be substantially increased through a team approach by identifying opportunities for improvements in management and helping ranch managers implement profitable practices. (J Am Vet Med Assoc 2004;225:210–220)

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in Journal of the American Veterinary Medical Association