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A total of 269 steers produced in a four-breed diallel mating design of Simmental, Limousin, Polled Hereford, and Brahman breeds were evaluated for the unadjusted and maintenance-adjusted total feed intake to total weight gain ratio. Time on feed ranged from 184 to 251 d. Covariate adjustments were made separately for age- and 12th rib fat-constant end points. Purebred, general combining ability, and maternal effects and heterosis were estimated. Effects of year, breed of dam, slaughter group, and days on feed accounted for most of the variation in feed conversion. Significantly higher unadjusted cumulative feed/gain ratios were found for steers from Brahman sires and for those from Simmental, Limousin, and Brahman dams. Adjustment to either fat- or age-constant values did not rerank breed groups, but a small reduction in the differences between these groups was detected for fat-constant efficiency. For maintenance-adjusted feed intake, progeny of Simmental and Limousin dams were less efficient than those of Polled Hereford and Brahman dams. Negative values for general combining ability, maternal effects, and heterosis would indicate less feed required per unit of weight gain. General combining ability for Polled Hereford crosses was negative and significant for cumulative feed/gain ratios, but no difference among dam breeds was found for the maintenance-adjusted ratio. Maternal effects for Limousin dams were positive and significant for all maintenance-adjusted ratios. Heterosis estimates for specific breed crosses were generally negative and ranged from -.87 to .22. 相似文献
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Efficacy of mitoxantrone against various neoplasms in dogs 总被引:2,自引:0,他引:2
G K Ogilvie J E Obradovich R E Elmslie D M Vail A S Moore R C Straw K Dickinson M F Cooper S J Withrow 《Journal of the American Veterinary Medical Association》1991,198(9):1618-1621
One hundred twenty-six dogs with histologically confirmed, measurable malignant tumors were evaluated in a prospective study to determine the response to the antineoplastic drug mitoxantrone. Ninety-five dogs had been refractory to one or more treatment modalities (surgery, n = 57; chemotherapy other than mitoxantrone, n = 37; radiation, n = 4; whole body hyperthermia, n = 1). The extent of neoplastic disease was determined immediately before each dose of mitoxantrone was administered (1 to 10 doses, 2.5 to 5 mg/m2 of body surface area, IV) 21 days apart. Each dog was treated with mitoxantrone until the dog developed progressive disease or until the dog's quality of life diminished to an unacceptable level as determined by the owner or attending veterinarian. A partial or complete remission (greater than 50% volume reduction) was obtained in 23% (29/126) of all dogs treated. Tumors in which there was a partial or complete remission included lymphoma (11/32), squamous cell carcinoma (4/9), fibrosarcoma (2/9), thyroid carcinoma (1/10), transitional cell carcinoma (1/6), mammary adenocarcinoma (1/6), hepatocellular carcinoma (1/4), renal adenocarcinoma (1/1), rectal carcinoma (1/1), chondrosarcoma (1/2), oral malignant melanoma (1/12), cutaneous malignant melanoma (1/1), myxosarcoma (1/1), mesothelioma (1/1), and hemangiopericytoma (1/1). Our results indicated that mitoxantrone induces measurable regression in various malignant tumors in dogs. 相似文献
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Systemic trichomoniasis was responsible for severe morbidity and mortality in a commercial squab operation. Squabs of 1 to 3 weeks of age were primarily affected. Extensive caseous necrosis of the liver, heart, lung, and intestinal mesentery was observed grossly. Histologically, extensive heterophilic inflammation surrounded the necrotic areas and was observed perivascularly in areas that were uninvolved grossly. Numerous trichomonads were demonstrated in affected tissues with Bodian's silver stain. 相似文献
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D W Hird K H Christiansen M D McBride A A Bickford R P Chin G L Cooper C U Meteyer B R Charlton K P Snipes C Danaye-Elmi 《Avian diseases》1991,35(4):723-727
Six hundred fourteen meat turkeys were submitted for necropsy from 24 California ranches as part of the National Animal Health Monitoring System (NAHMS). Enteritis was the most frequent pathologic diagnosis in birds 18 days old or younger and the second most frequent diagnosis in birds 19-70 days old. Hemorrhagic enteritis was the most frequent diagnosis in birds aged 19-70 days. Tibial dyschondroplasia, bronchopneumonia, and ascaridiasis were ranked one through three in frequency of diagnoses in birds over 70 days of age. Salmonella was isolated from 71% of flocks tested, and Mycoplasma meleagridis was isolated from 33% of tested flocks over 70 days of age. Antibodies to several disease agents were detected, including hemorrhagic enteritis (100% of flocks over 70 days old) and Newcastle disease (63% of flocks over 70 days old). 相似文献
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Pharmacokinetics of norfloxacin in dogs after single intravenous and single and multiple oral administrations of the drug 总被引:3,自引:0,他引:3
S A Brown J Cooper J J Gauze D S Greco D W Weise J M Buck 《American journal of veterinary research》1990,51(7):1065-1070
Norfloxacin was given to 6 healthy dogs at a dosage of 5 mg/kg of body weight IV and orally in a complete crossover study, and orally at dosages of 5, 10, and 20 mg/kg to 6 healthy dogs in a 3-way crossover study. For 24 hours, serum concentration was monitored serially after each administration. Another 6 dogs were given 5 mg of norfloxacin/kg orally every 12 hours for 14 days, and serum concentration was determined serially for 12 hours after the first and last administration of the drug. Complete blood count and serum biochemical analysis were performed before and after 14 days of oral norfloxacin administration, and clinical signs of drug toxicosis were monitored twice daily during norfloxacin administration. Urine concentration of norfloxacin was determined periodically during serum acquisition periods. Norfloxacin concentration was determined, using high-performance liquid chromatography with a limit of detection of 25 ng of norfloxacin/ml of serum or urine. Serum norfloxacin pharmacokinetic values after single IV dosing in dogs were best modeled, using a 2-compartment open model, with distribution and elimination half-lives of 0.467 and 3.56 hours (harmonic means), respectively. Area-derived volume of distribution (Vd area) was 1.77 +/- 0.69 L/kg (arithmetic mean +/- SD), and serum clearance (Cls) was 0.332 +/- 0.115 L/h/kg. Mean residence time was 4.32 +/- 0.98 hour. Comparison of the area under the curve (AUC; derived, using model-independent calculations) after iv administration (5 mg/kg) with AUC after oral administration (5 mg/kg) in the same dogs indicated bioavailability of 35.0 +/- 46.1%, with a mean residence time after oral administration of 5.71 +/-2.24 hours. Urine concentration was 33.8 +/- 15.3 micrograms/ml at 4 hours after a single dose of 5 mg/kg given orally, whereas concentration after 20 mg/kg was given orally was 56.8 +/- 18.0 micrograms/ml at 6 hours after dosing. Twelve hours after drug administration, urine concentration was 47.4 +/- 20.6 micrograms/ml after the 5-mg/kg dose and 80.6 +/- 37.7 micrograms/ml after the 20/mg/kg dose.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
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An isocratic liquid chromatographic (LC) technique is described for the determination of benzoic acid and sorbic acid in foods such as beverages, fruits, seafood, vegetables, sauces, and dairy, bakery, and confectionery products. A C18 column is used with methanol-phosphate buffer (5 + 95) as mobile phase and 4-hydroxyacetanilide or 3,5-dinitrobenzoic acid as internal standard. Sample preparation is simple, rapid, and produces a sample extract that has a minimum effect on the column performance and life. Specificity of the method was checked against common food additives such as L-ascorbic acid, caffeine, artificial sweeteners (saccharin, cyclamate, aspartame), antioxidants (BHT, BHA) and artificial colors. Also described are 2 procedures for confirmation of the preservatives, using either redox reaction of sorbic acid with potassium permanganate or gas chromatography/mass spectrometry. Mean recoveries of 90-105% were obtained with a precision of 1-6% and a detection limit of 20 mg/kg for the 2 preservatives. 相似文献