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高致病性禽流感免疫的管理环节 总被引:1,自引:0,他引:1
一 严管疫苗生产环节
兽用生物制品生产厂家多,品种较多,质量不一,免疫效果各异,特别是高致病性禽流感疫苗,由于生产时间较短,疫苗质量不够稳定,副作用较为严重,包装规格单一,技术服务滞后.严重地影响了高致病性禽流感的免疫效果。如有的厂家疫苗生产的批准文号和疫苗产品不相符。有的中试产品或有临时批准文号的疫苗,不按规定范围随意大面积推广,有的同一厂家生产的疫苗,不同批次质量不一,免疫效果差异较大。 相似文献
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Strategies for Using eFSH for Superovulating Mares 总被引:1,自引:0,他引:1
Patrick M. McCue DVM PhD Melissa Patten BS David Denniston PhD Jason E. Bruemmer PhD Edward L. Squires PhD 《Journal of Equine Veterinary Science》2008,28(2):91-96
The standard treatment for superovulation of mares is to administer equine follicle-stimulating hormone (eFSH) for 4 to 5 days to stimulate multiple follicles and human chorionic gonadotropin (hCG) to induce synchronous ovulations. Objectives of this study were: (1) to determine whether a short-term (3-day) eFSH treatment protocol would result in similar ovulation and embryo recovery rates compared with the standard eFSH protocol; (2) to determine the efficacy of a decreasing dose of eFSH (step-down protocol) on ovulation rate and embryo recovery; (3) to compare the efficacy of hCG and recombinant equine luteinizing hormone (reLH) for inducing ovulation in FSH-treated mares; and (4) to compare embryo recovery rates and embryo size when mares are flushed at 6.5 or 7.0 days after ovulation. Forty light-horse mares were used in 2005 (experiment 1) and 20 different mares were used in 2006 (experiment 2). In experiment 1, mares were randomly assigned to one of three treatment groups: (1) untreated controls, (2) standard eFSH treatment (12.5 mg intramuscularly twice daily), and (3) 3-day eFSH treatment. In experiment 2, mares were randomly assigned to one of four treatments: (1) untreated controls, (2) standard eFSH protocol, (3) 3-day eFSH treatment, and (4) step-down eFSH treatment (12.5 mg twice daily day 1, 8.0 mg twice daily day 2, 4.0 mg twice daily day 3). Within each treatment, mares were given either hCG (2,500 IU) or equine LH (750 mg, EquiPure LH; reLH) to induce synchronized ovulations. Embryo recovery was performed either 6.5 or 7.0 days after ovulation. In experiment 1, numbers of preovulatory follicles and ovulations were less for mares in the 3-day treatment group than the standard group, but were greater than for controls. Embryo recovery per flush was higher in the standard group (2.6) than the 3-day eFSH treatment (0.8) or control groups (0.8). In experiment 2, the number of preovulatory follicles and number of ovulations were greater in the standard and 3-day treatment groups than in control and step-down groups. The percent embryo recovery per ovulation and mean embryo grade were similar for all groups; however, the embryo recovery per flush was higher for mares in the standard treatment than controls (1.3 vs 0.6) but was similar to the 3-day (1.1) and step-down (0.8) treatments. Embryo recovery was similar for flushes performed on days 6.5 and 7.0 post-ovulation. The percentage of control mares ovulating within 48 hours in response to hCG or reLH was similar. In contrast, a higher percentage of eFSH-treated mares ovulated within 48 hours in response to reLH than hCG (92% vs 71%). In both years, the 3-day eFSH treatment protocol resulted in a greater number of preovulatory follicles and a greater number of ovulations than untreated controls. Unfortunately, the increased ovulation rate for mares administered eFSH for 3 days did not result in a greater number of embryos recovered per flush in either year. Use of a step-down eFSH treatment protocol resulted in fewer preovulatory follicles, fewer ovulations, and fewer embryos as compared with the standard eFSH treatment. In conclusion, the standard eFSH treatment resulted in a greater embryo recovery rate per cycle than either the 3-day or step-down treatment protocols. Recombinant equine LH was more effective than hCG in causing ovulation in eFSH-treated mares. 相似文献
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Mariana Ftima Z. F. Nogueira Simara M. Marcato Antnio C. Furlan Vittor Zancanela Eline Maria Finco Daiane de O. Grieser Caroline E. Stanquevis Taciana M. de Oliveira‐Bruxel 《Animal Science Journal》2019,90(7):870-879
Three experiments were carried out to determine the crude protein requirements for maintenance (CPm) and weight gain (CPg) of meat quail and to develop protein‐requirement prediction models. Experiment 1 was conducted to determine CPm by the nitrogen‐balance technique. The regression of nitrogen balance on nitrogen intake revealed a CPm requirement of 2.94 g/kg0.75/day. Experiment 2 was aimed at determining CPm by the comparative‐slaughter technique. Retained nitrogen (RN) and nitrogen intake (NI) were quantified considering the metabolic weight of the birds. The linear regression of RN on NI provided a CPm estimate of 6.63 g/kg0.75/day. Experiment 3 was conducted to determine CPg. The regression of body nitrogen from the carcasses on fasted body weight revealed CPg estimates of 407.68 (0–7 days), 501.76 (8–14 days), 470.40 (0–14 days), 517.44 (15–21 days), 627.20 (22–28 days), 423.36 (29–35 days), and 517.44 mg/g (15–35 days). The protein‐requirement prediction models developed for meat quail aged 0–7, 8–14, 0–14, 15–21, 22–28, 29–35, and 15–35 days were CP = 2.94.W0.75 + 0.408.G; CP = 2.94.W0.75 + 0.502.G; CP = 2.94.W0.75 + 0.470.G; CP = 2.94.W0.75 + 0,517.G; CP = 2.94.W0.75 + 0.627.G; CP = 2.94.W0.75 + 0.423.G; CP = 2.94.W0.75 + 0.517.G, respectively, where: W0.75 = metabolic weight (kg), and G = daily weight gain (g). 相似文献
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Transgenic pigs for xenotransplantation for humans] 总被引:1,自引:0,他引:1
H Niemann 《DTW. Deutsche tier?rztliche Wochenschrift》1999,106(4):141-146
Transgenic livestock have been generated via microinjection of DNA-constructs into pronuclei of zygotes. However, efficiency is low and only 1-3% transgenic offspring are to be obtained. Integration of the transgene occurs at random and expression is independent from the number of integrated copies but can be affected by the integration site. To overcome the shortage of human organs, transgenic pigs have been generated that express human complement regulatory genes. This approach enables to overcome the hyperacute rejection response as shown by an average survival rate (40-90 days) of the immunosuppressed primate recipients receiving a heart from a transgenic pig. It is expected that transgenic pigs would be available as organ donors in the next 5-10 years. A major prerequisite, however, is the prevention of the potential transfer of pathogenic microorganisms, in particular porcine endogenous retroviruses (PERV). Improvements of the efficiency in the generation of transgenic pigs will be achieved by the use of genetically modified donor cells in nuclear transfer technology (cloning). 相似文献
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新的数学分支学科和边缘学科不断涌现,并且同一研究方向也有很多更细的分支,其研究方法和对象有很大的区别。在选择审稿人的时候将其仔细区别,约请合适的审稿人,否则达不到很好的审稿效果。文中提出可以从整理编辑部资料、通过CNKI寻找审稿人、根据参考文献找审稿人及整理本校教师资料这四个方砸寻找合适的数学审稿人。 相似文献
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Silvia Colleoni PhD Irina Lagutina PhD Giovanna Lazzari DVM PhD Heriberto Rodriguez-Martinez Prof. DVM Cesare Galli Prof. DVM Jane M. Morrell BVetMed PhD 《Journal of Equine Veterinary Science》2011,31(9):536-541
Improved sperm selection techniques are needed to increase the efficiency of equine-assisted reproduction. Single layer centrifugation (SLC) of spermatozoa has been shown to improve the quality of stallion sperm samples. In this study, the functionality of selected stallion spermatozoa was tested by intracytoplasmic sperm injection of equine oocytes after selection by SLC through Androcoll-E or by discontinuous density gradient centrifugation (DGC) through Redigrad and Tyrode's medium with added albumin, lactate, and pyruvate. The mean cleavage rates of the injected oocytes from SLC- and DGC-selected spermatozoa were 67% and 66%, respectively, whereas the proportion of blastocysts developing from cleaved oocytes was 28% and 22%, respectively (P > .05, not significant). An incidental finding was that there was a tendency for SLC-selected spermatozoa to have a higher percentage of spermatozoa with normal morphology than DGC (70% ± 22% vs. 58% ± 38%) and for more blastocysts to be obtained from subfertile ejaculates (21 [19.6%] vs. 15 [14.4%], respectively). In further experiments, stallion spermatozoa bound to hyaluronan, although binding may depend on the semen extender and sperm treatment as well as incubation time. In conclusion, SLC-selected stallion spermatozoa function normally when injected into oocytes. SLC may potentially be better than DGC at selecting spermatozoa from subfertile ejaculates, but this effect needs rigorous investigation with a much larger sample size. Use of the hyaluronan-binding assay for assessing the potential fertility of stallion spermatozoa may be useful but requires further evaluation. 相似文献
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为提高重组山羊痘病毒(GPV)中外源基因的表达水平及筛选强转录效力的启动子,本研究选择桑灯蛾昆虫痘病毒42K启动子(42K)、痘病毒合成晚期441启动子(SL441)、痘病毒合成晚期454启动子(SL454)、牛痘病毒(VV)早晚期P7.5启动子(P7.5)、VV晚期P11启动子(P11)、VV H6启动子(H6)、VV合成早晚期启动子(E/L)及人工优化早晚期启动子(LEO)8种启动子,并在其下游插入萤火虫荧光素酶(Fluc)报告基因,分别构建了启动子效力检测重组质粒。并分别将其转染于预感染GPV的DF-1(鸡)、LT(绵羊)、BHK-21(仓鼠)和Vero(猴)4种动物源细胞中,以表达海肾荧光素酶(Rluc)的p RL-TK为内参质粒,24 h后检测荧光素酶活性。结果表明,在LT细胞中,SL441转录效力最强;在DF-1细胞中,LEO转录效力最强,为其他启动子的1.19~14.46倍;在Vero细胞中,H6和SL441的转录效力较强,达到其他启动子的1.21~11.24倍;在BHK-21中,H6启动子的转录效力也显著强于其它启动子。本实验最终确定了GPV在4种动物源细胞中转录效力强的启动子,该研究结果为进一步提高以GPV为载体疫苗的免疫效力奠定了基础。 相似文献
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The construction of a simple, portable restrainer for holding sheep in either the horizontal or vertical position for abdominal radiography is described. Examples of its use in locating slow-release pellets and needles are given. 相似文献