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Efficacy of parenteral antibiotics for disease prophylaxis in feedlot calves 总被引：9，自引：9，他引：0 
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下载免费PDF全文 Harland RJ Jim GK Guichon PT Townsend HG Janzen ED 《The Canadian veterinary journal. La revue veterinaire canadienne》1991,32(3):163-168
Trimethoprim-sulfadoxine (TMPSDX) and two formulations of oxytetracycline (OTC) were examined for their prophylactic efficacy in feedlot calves when given by intramuscular injection on arrival at a large commercial feedlot. The study included 2,112 high-risk feeder calves that developed disease early in the feeding period. Both formulations of OTC reduced bovine respiratory disease morbidity during the first two weeks on feed and for the entire feeding period by 15-19% (p<0.05), and they also reduced all fatal fibrinous pneumonia by 67% and 84% (p<0.05). All three drugs significantly reduced all fatal disease in animals first treated during the second week on feed, but not for the overall feeding period. Oxytetracycline with 2-pyrrolidone reduced the incidence of all fatal disease by 44% (p<0.05) during the entire feeding period. The case fatality risk for calves first treated during the second week on feed was lower (p<0.05) in the TMPSDX group and in the OTC with polyvinyl-pyrrolidone group. 相似文献
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Jim GK Ribble CS Guichon PT Thorlakson BE 《The Canadian veterinary journal. La revue veterinaire canadienne》1991,32(10):613-617
A 90-day finishing trial involving 144 feedlot heifers was conducted to compare the performance parameters and carcass characteristics of open heifers, therapeutically aborted heifers, and pregnant heifers. In the first 28 days of the trial, the aborted heifers had reduced (p < 0.05) feed intake (FI), average daily gain (ADG), and feed efficiency (FE) compared to pregnant and open heifers. Over the entire trial, on a live weight basis, the aborted group had reduced (p < 0.05) final weight, ADG, and FE compared to pregnant and open heifers. However, when the data were adjusted for total uterine weight, the aborted and open heifers had improved (p < 0.05) final weight, ADG, and FE compared to pregnant heifers. The aborted and open group had a higher (p < 0.05) carcass weight, rib eye area, dressing percentage, and cutability estimate compared to the pregnant heifers. The aborted group had lower (p < 0.05) carcass weight than the open heifers. Over the entire 90-day feeding period, there were no statistically significant differences among the groups with respect to feed intake (FI), average fat, grade fat, and carcass grades. Also, there were no significant health problems or mortality in any of the groups.
In the economic analysis, aborted heifers returned $26.41 per head more than pregnant heifers. Open heifers returned $39.94 per head more than aborted heifers, and $66.35 more than pregnant heifers. Thus, aborting feedlot heifers during the second trimester was determined to be a safe and cost effective management decision.
相似文献5.
A survey of the selenium status of beef cows in Alberta. 总被引：1，自引：1，他引：0
J R Campbell G K Jim C W Booker P T Guichon 《The Canadian veterinary journal. La revue veterinaire canadienne》1995,36(11):698-702
An epidemiological survey was conducted in Alberta to measure the selenium status in blood of beef cows during the fall and to determine the risk of selenium deficiency among specific geographic regions of Alberta. Three census divisions of Alberta based on the Statistics Canada Census of Agriculture were chosen as the study areas for the project. Soils and plants in area A (Edmonton area) and area B (Calgary area) were known to be deficient in selenium, while soils and plants in area C (southeast corner of Alberta) were known to have adequate levels of selenium. Blood samples were collected from 335 cows on 29 farms from the 3 study areas. These samples were collected from cows that had recently been removed from pasture in October and November 1992. Answers to a short questionnaire pertaining to various herd characteristics and management practices were also obtained for each herd. The average value of selenium for all cows sampled was 2.20 mumol/L. The average value of selenium of cows in areas A and B was 1.93 mumol/L. The average value of selenium of cows in area C was significantly (P < 0.05) higher at 2.70 mumol/L. Nine percent of the cows in the study were considered marginal or deficient in selenium (< 1.27 mumol/L selenium). Herds located in area C, herds that were provided with supplemental feed on pasture, and herds that were pregnancy checked had higher average herd selenium values than did other herds. Cow-calf producers located in areas with selenium-deficient soils should pay particular attention to selenium supplementation for their cows. Some of the negative "geographic" effects on selenium values can be overcome by more progressive management practices. 相似文献
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Booker CW Abutarbush SM Schunicht OC Jim GK Perrett T Wildman BK Guichon PT Pittman TJ Jones C Pollock CM 《Veterinary therapeutics : research in applied veterinary medicine》2007,8(3):183-200
The purpose of this study was to determine the efficacy and cost-effectiveness of tulathromycin (DRAX) versus tilmicosin (MIC) or oxytetracycline (TET) as a metaphylactic antimicrobial in feedlot calves. Calves that received DRAX had significantly (P<.05) lower initial undifferentiated fever (UF) treatment and relapse rates; lower overall chronicity, overall mortality, and cause-specific mortality rates; higher average daily gains; and improved quality grades. However, calves that received DRAX also had poorer (P<.05) yield grades compared with calves that received MIC or TET and worse feed conversion compared with calves that received MIC. Net advantages in the DRAX group were 3.79CanDollars/animal and 16.96CanDollars/animal compared with the MIC and TET groups, respectively. Based on these results, DRAX is a more efficacious and cost-effective metaphylactic antimicrobial than MIC or TET in feedlot calves at ultra-high risk of developing UF. In addition, this study presents a comparison between two methods ("deads out" and "deads in") of calculating feedlot performance variables. 相似文献
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C Waldner J Campbell G K Jim P T Guichon C Booker 《The Canadian veterinary journal. La revue veterinaire canadienne》1998,39(4):225-231
Three tests are routinely done to assess blood status of selenium in cattle: serum selenium, whole blood selenium, and glutathione peroxidase. The objective of this study was to compare the various analytical methods for determining blood selenium status in groups of mature cows and beef calves. Twenty to 30 blood samples per herd were collected from 8 beef herds in central Alberta and 1 dairy in Alberta herd twice a year from the spring of 1992 through the fall of 1995, and once from 185 spring calves in 2 beef herds in Saskatchewan. Serum and whole blood samples were submitted to 1 laboratory and whole blood samples were submitted to a 2nd laboratory. Samples for glutathione peroxidase determinations were submitted to a 3rd laboratory. Pearson's correlation coefficients and Cohen's kappa were calculated for each possible comparison among the different measures. The best agreement was observed between serum and whole blood analysis within Laboratory A. The remaining comparisons reflected poor agreement. Comparison of herd-level assessment resulted in better agreement than comparison of individual sample results among laboratories and procedures for all combinations tested. Serum selenium analysis was the only laboratory procedure for which external reference material was utilized. Serum selenium, whole blood selenium, and glutathione peroxidase measure different compartments of the blood selenium pool. The time frame of interest, supplementation practices, and the stability of recent dietary intake determine the optimum assessment method for individual animals or herds. Determination of the serum status or of blood selenium is more consistently measured at the herd-level than for individual samples. 相似文献
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PT Sprunger L Petersen EW Plummer E Laegsgaard F Besenbacher 《Science (New York, N.Y.)》1997,275(5307):1764-1767
Large-amplitude electron density oscillations were observed on a Be(0001) surface by means of variable-temperature scanning tunneling microscopy. Fourier transforms of the images showed a ring of radius 2kF, where kF is the Fermi wave vector of the Be(0001) surface state. This wavelength was expected from Friedel oscillations caused by electronic screening of surface defects, but the amplitude of the waves for energies near the Fermi energy was anomalously large and inconsistent with the Friedel concept of screening. The enhanced amplitude of the waves must be a many-body effect, either in the electron gas (possibly an incipient charge density wave) or in the response of the lattice (electron-phonon coupling). 相似文献