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981.
疫病是世界养禽生产效率的主要限制因素。尽管分子生物学方面的基础研究导致了新型疫苗的出现,但集约化生产体系仍受到新的和变异疫病的危害,这常常是多因子感染造成的。本文综述了一些重要疫病复合症的研究进展并对商品蛋鸡群和肉鸡生产效益的影响作一评述。 相似文献
982.
ismail M 《Veterinary research communications》2007,31(4):467-476
The pharmacokinetics of difloxacin (Dicural) was studied in a crossover study using three groups (n = 4) of male and female Friesian calves after intravenous (i.v.), intramuscular (i.m.) and subcutaneous (s.c.) administrations
of 5 mg/kg body weight. Drug concentration in plasma was determined by high-performance liquid chromatography using fluorescence
detection. The plasma concentration–time data following i.v. administration were best fitted to a two-compartment open model
and those following i.m. and s.c. routes were best fitted using one-compartment open model. The collected data were subjected
to a computerized kinetic analysis. The mean i.v., i.m. and s.c. elimination half-lives (t
1/2β) were 5.56 ± 0.33 h, 6.12 ± 0.42 h and 7.26 ± 0.6 h, respectively. The steady-state volume of distribution (V
dss) was 1.12 ± 0.09 L/kg and total body clearance (ClB) was 2.19 ± 0.1 ml/(min. kg). The absorption half lives (t
1/2ab) were 0.38 ± 0.027 h and 2.1 ± 0.09 h, with systemic bioavailabilities (F) of 96.5% ± 6.4% and 84% ± 5.5% after i.m. and s.c. administration, respectively. After i.m. and s.c. dosing, peak plasma
concentrations (C
max) of 3.38 ± 0.13 μg/ml and 2.18 ± 0.12 μg/ml were attained after (t
max) 1.22 ± 0.20 h and 3.7 ± 0.52 h. The MIC90 of difloxacin for Mannheimia haemolytica was 0.29 ± 0.04 μg/ml. The AUC/MIC90 and C
max/MIC90 ratios for difloxacin following i.m. administration were 120 and 11.65, respectively and following s.c. administration were
97.58 and 7.51, respectively. Difloxacin was 31.7–36.8% bound to calf plasma protein. Since fluoroquinolones display concentration-dependent
activities, the doses of difloxacin used in this study are likely to involve better pharmacodynamic characteristics that are
associated with greater clinical efficacy following i.m. administration than following s.c. administration. 相似文献
983.
Gross,histologic, and computed tomographic characterization of nonpathological intrascleral cartilage and bone in the domestic goat (Capra aegagrus hircus) 下载免费PDF全文
984.
985.
The number of donkeys and mules throughout the world is stable, and awareness of their use and concern for welfare, pain recognition and treatment are receiving increasing veterinary interest. Therefore, accurate information about anaesthesia and analgesia in donkeys and mules is important to ever more equine practitioners. Since donkeys are physiologically and pharmacologically different from horses, knowledge on species specific aspects of anaesthesia and analgesia are very important. Mules combine elements from both donkey and horse backgrounds, leading to great diversity in size, temperament and body type. Physiologically, they seem to resemble horses more than donkeys. This review highlights the current knowledge on various anaesthetic and analgesic approaches in donkeys and mules. There is still much information that is not available about donkeys; in many circumstances, the clinician must use available equine information to treat the patient, while monitoring carefully to observe for differences in response to therapy compared to the horse. 相似文献
986.
M J Burridge M C Thurmond J M Miller M J Schmerr M J Van Der Maaten 《American journal of veterinary research》1982,43(10):1866-1867
The duration of detectable colostral antibodies to the glycoprotein antigen of bovine leukemia virus was studied in calves which were born to bovine leukemia virus-infected cows, but showed no serologic evidence of prenatal infection. Colostral antibodies detectable by an agar-gel immunodiffusion test (AGIT) persisted for less than 1 month to 6 months (mean 2.9 months) in the 139 calves examined. Colostral antibodies were detectable 1 to 5 months longer by radioimmunoprecipitation assay than by the AGIT in 22 of the 24 calves studied comparatively. The mean duration of colostral antibodies in those 24 calves was 3.8 months (min-max, 2 to 6 months) for the AGIT and 6.0 months (min-max, 4 to 9 months) for the radioimmunoprecipitation assay. 相似文献
987.
988.
Y Li H N Kadarmideen J C M Dekkers 《Zeitschrift für Tierzüchtung und Züchtungsbiologie》2008,125(5):320-329
The purpose of this study was to develop and investigate selection strategies that aim at maximizing long-term genetic response while conserving gene diversity and controlling inbreeding in populations of limited effective size, assuming complete knowledge of all genes affecting a quantitative trait. Three selection strategies were proposed to select on 100 quantitative trait loci (QTL) and compared with truncation selection on breeding value. Alternative selection strategies aimed at maximizing the average breeding value of parents with a penalty on (1) the number of unfavourable QTL genotypes among parents (OS-I), (2) the negative of the logarithm of the frequency of the favourable allele at each QTL among parents (OS-II), and (3) the average pedigree relationship among parents (OS-III). When all QTL and their effects were known, the strategies examined were able to obtain extra long-term responses, conserve QTL diversity and reduce inbreeding, compared with truncation selection. Strategy OS-II was the most effective in conserving QTL diversity and OS-III in reducing inbreeding. By changing the magnitude of the penalties applied, the impact on long-term response, inbreeding and diversity can be controlled. Extra long-term responses over truncation selection of OS-I and OS-II were even greater when effects of QTL were estimated rather than assumed known, indicating the applicability of results to practical strategies for marker-assisted selection. Extra responses are expected to be reduced for larger population sizes. 相似文献
989.
Comparative toxicology of monensin sodium in laboratory animals 总被引:3,自引:0,他引:3
The toxicology of monensin has been studied in several laboratory animal species. There was considerable species variation in acute oral LD50 values. The consistent signs of acute toxicity were: anorexia, hypoactivity, skeletal muscle weakness, ataxia, diarrhea, decreased weight gain and delayed deaths. The 3-mo study in rats fed diets containing 0, 50, 150 or 500 ppm monensin resulted in no effects at the lowest dose level, slight reduction of body weight gain in the middle-dose group and severe depression in body weight gain, skeletal and cardiac lesions, and deaths in the highest dose group. The 3-mo study in dogs given daily oral doses of 0, 5, 15 or 50 mg/kg monensin resulted in no effects at the lowest dose level. Dogs in the 15 and 50 mg/kg groups developed, during test wk 1 to 4, anorexia, weakness, ataxia, labored respiration, body weight loss, increased serum muscle enzyme values, severe skeletal muscle degeneration and necrosis with less severe heart lesions and deaths. Mice fed diets containing 0, 37.5, 75, 150 or 300 ppm monensin for 3 mo had reduced body weight gain in all test groups but no other physical signs. Serum creatine phosphokinase (CPK) values were increased in mice in the two highest dose groups and minimal heart lesions were found in the highest dose group. Dogs given daily oral doses of 0, 1.25, 2.5, 5 or 7.5 mg/kg monensin for 1 yr survived with no evidence of toxicity in the two lowest dose groups.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
990.
Forsyth L.M.G. Jackson L.A. Wilkie G. Sanderson A. Brown C.G.D. Preston P.M. 《Veterinary research communications》1997,21(4):249-263
Forsyth, L.M.G., Jackson, L.A., Wilkie, G., Sanderson, A., Brown, C.G.D. and Preston, P.M., 1997. Bovine cells infected in vivo with Theileria annulata express CD11b, the C3bi complement receptor. Veterinary Research Communications, 21 (4), 249-263Bovine cells from cattle infected with Theileria annulata were phenotyped with monoclonal antibodies recognizing bovine leukocyte antigens. Macroschizont-infected, transformed cell lines prepared from peripheral blood mononuclear cells of cattle, infected with sporozoites, were assessed by flow cytometry; parasitized cells in tissues from infected cattle were examined by immunocytochemical techniques. Co-expression of markers for different cell lineages by the cell lines precluded a definite conclusion as to their phenotypic origins. For, while the pattern of leukocyte antigens expressed by these in vivo-derived schizont-infected cells, which included CD11b, was indicative of a myeloid origin, the possibility that they were NK cells could not be excluded. The monoclonal antibody (MAb) IL-A15, which recognizes CD11b, reacted with a high proportion of parasitized cells in sections of tissues from infected cattle at all stages of acute disease. Mononuclear cells infected with parasites at all stages of differentiation, from macroschizont to microschizont, expressed CD11b. Such parasitized cells occurred throughout the lymphoid tissues, being found in the thymus, spleen and lymph nodes, particularly the prescapular node draining the site of infection, the hepatic, mesenteric and precrural nodes, as well as in the reticulo-endothelial tissue of the liver, kidney, lung, abomasum, adrenal and pituitary glands. These observations provided the first evidence for a myeloid origin for the parasitized T. annulata cells found in infected bovine tissues and blood and suggested a mechanism whereby schizonts could transfer from cell to cell during mechanical infection with schizont-infected cells. 相似文献