Active Participation Instead of Passive Behaviour Opens Up New Vistas in Education of Veterinary Anatomy and Histology

Teaching morphology, a fundamental part of medicine curricula is traditionally based on lectures and practical trainings. We introduced peer-assisted learning (PAL) and student expert teams to the courses to give the students the possibility to improve their free speech and self-confidence. We involved students in active preparation of online materials such as labelled e-slides and e-pics . We offered online digital microscopy (Zoomify^TM) and dissection (CyberPrep) allowing repeating the learned material and studying veterinary morphology outside the dissection theatre. Over 60% of first and third semester students profited from being a peer or being taught by a peer and 50% said the expert teams were an excellent method to learn the topographic anatomy. Almost all students applied Zoomify^TM and CyberPrep and 75% of them found the digital microscopy and dissection to be a helpful or very helpful learning tool. In face of reduced contact hours, these forms of education compensated in part the lost teaching time. We observed improvement of rhetoric and presentation skills and self-confidence. The approaches should therefore find their constant place in the veterinary medicine curricula.     

革兰氏阴性菌蛋白分泌系统研究进展

许多革兰氏阴性细菌借助于细菌的分泌系统,分泌出毒性因子和效应子,与寄主进行分子交流。革兰氏阴性细菌有5种类型蛋白质分泌系统,即Ⅰ-V型。本文结合这5种分泌系统的特点、组成以及转运机制方面的进展进行了综述。     

A Quantitative Flurometric Assay for the Measurement of Antibody to Pasteurella haemolytica in Cattle

A rapid, simple fluorometric method is described for measuring antibody to Pasteurella haemolytica in sera of cattle. Various antigen preparations were compared for the test including live, formalin-killed and phenol-killed P. haemolytica. A preparation composed of formalin-killed organisms from a 22 hour culture gave consistent results and was used in the studies. The test was reproduciable with percent coefficients of variation for fluorescent signal unit values on ten or more replicate samples ranging from 5.7 to 28.0. Sera from calves vaccinated by aerosol exposure to live P. haemolytica had up to a five-fold increase in antibody titer as measured by the flurometric method test during a 21 day period. Fluorometric method titers were comparable to those obtained by the indirect bacterial agglutination test. There was no seroconversion to P. haemolytica in calves vaccinated by aerosol exposure of P. multocida. The major advantages of the fluorometric method test over conventional methods are that the assay does not require serial dilutions of serum samples and thus limits time and effort to determine antibody titers.     

A mail survey of factors associated with morbidity and mortality in feedlot calves in southwestern Ontario.

The design and results of a mail survey of a simple random sample of southwestern Ontario feedlot owners are presented. The survey provided general data about management of feedlot calves and the association between a number of factors and disease and/or death rates. The number of calves purchased was related positively, in a linear manner, to mortality and morbidity rates. Increased levels of morbidity and mortality were noted when the ration was changed to corn silage from dry-hay within the first month after arrival. However, it was not clear whether the ration changes preceded or followed increased rates of morbidity and mortality. Prophylactic levels of antimicrobials in the water supply were associated with increased death losses. Shipping cattle by truck, rather than train, was associated with decreased rates of disease. Processing factors, including using vaccines against respiratory disease, were not associated significantly with mortality or morbidity. It was concluded that reducing the number of calves, to approximately 100 per group, not changing the ration to silage within the first month and not using antibiotics in the water supply on arrival could significantly reduce disease and death losses.     

Development and evaluation of an endoscopic technique permitting rapid visualization of the cardiac region of the porcine stomach.

Our study was designed to ascertain whether a flexible videoscope could be used to efficiently monitor ulcers of the pars esophagea in a large group of grower-finisher swine. Gastroscopy was performed on 2 separate occasions in 32 pigs following anesthesia with intravenous pentobarbital, and ulcers of the pars esophagea were subjectively graded. The pigs were then necropsied. Grades from the second endoscopic examination were compared for agreement with grades derived from gross inspection of the pars esophagea at necropsy, and with grades derived from histopathologic examination of sections of the same region. The pars esophagea was adequately visualized in all endoscopic examinations. The average duration of each examination, from anesthetic induction, was approximately 8 min. Gastroscopy permitted appreciation of a wide range of focal and diffuse superficial and deep ulcerative lesions of the pars esophagea, but failed to unequivocally identify parakeratosis of the pars esophagea. Agreement between endoscopic and subsequent necroscopic and histopathologic gradings of ulcerations was poor. We concluded that the use of a flexible videoscope permitted rapid inspection of the pars esophagea, and was therefore a practical method of experimentally monitoring the progression of spontaneous gastric ulcers in pigs. We also postulated that the poor agreement between endoscopic and postmortem findings occurred because endoscopy was possibly more sensitive at detecting small and superficial ulcerations. However, further studies are needed to verify the accuracy of endoscopic diagnosis of gastric ulcers in the live pig.     

Biochemistry reference values for Quebec lactating dairy cows, nursing sows, growing pigs and calves.

Reference values for lactating dairy cows, nursing sows, growing calves and pigs were established on jugular cannulated animals. On each day of sampling, 13 samples were taken every hour from dairy cattle, growing calves and pigs and 5 samples were taken every 2 h from nursing sows to minimize day and analysis bias. Results show that aging influences more biochemical factors in pigs than in calves, and in nursing sows variations observed between day 5 and 15 after farrowing are of greater amplitude than between day 15 and 25.     

Hsp70 enhances presentation of FMDV antigen to bovine CD4+ T cells in vitro

Foot-and-mouth disease virus (FMDV) is the causative agent of a highly contagious acute vesicular disease affecting cloven-hoofed animals, including cattle, sheep and pigs. The current vaccine induces a rapid humoral response, but the duration of the protective antibody response is variable, possibly associated with a variable specific CD4⁺ T cell response. We investigated the use of heat shock protein 70 (Hsp70) as a molecular chaperone to target viral antigen to the Major Histocompatibility Complex (MHC) class II pathway of antigen presenting cells and generate enhanced MHC II-restricted CD4⁺ T cell responses in cattle. Monocytes and CD4⁺ T cells from FMDV vaccinated cattle were stimulated in vitro with complexes of Hsp70 and FMDV peptide, or peptide alone. Hsp70 was found to consistently improve the presentation of a 25-mer FMDV peptide to CD4⁺ T cells, as measured by T cell proliferation. Complex formation was required for the enhanced effects and Hsp70 alone did not stimulate proliferation. This study provides further evidence that Hsp70:peptide complexes can enhance antigen-specific CD4⁺ T cell responses in vitro for an important pathogen of livestock.     

庆阳市紫花苜蓿和燕麦推广利用现状

文章对紫花苜蓿、燕麦在庆阳市引进及在当地推广情况做了说明,结合试验对国内、国外筛选品种做了对比,推荐了适宜在庆阳市南部、北部地区种植的紫花苜蓿品种;同时对不同播期的燕麦产量做了比较,分析了燕麦不同部位营养成分。     

自由舔食补饲小苏打在高产奶牛疾病预防中的应用研究

[目的]饲喂碳酸氢钠能够参与反刍动物瘤胃酸碱调节并发挥重要的酸碱平衡作用。试验通过对比高产、中产、低产3个不同群体荷斯坦奶牛每头每日补饲不同剂量小苏打后,观察其对奶牛个体平均泌乳天数和日单产的影响,探究小苏打的最佳补饲量与补饲方法,为我国现阶段高产奶牛的饲管提供有价值的借鉴。[方法]对本场挤奶大厅1 000头泌乳牛连续16个月不间断全群补饲小苏打,以奶牛恶性舔土现象出现的次数以及临床热应激疾病发病数量作为瘤胃酸碱平衡的量化指标,分析各试验组的小苏打补饲量。[结果]高产群、中产群、低产群每头荷斯坦奶牛每日通过自由舔食分别平均获得61 g, 70 g, 80 g的小苏打,加上精饲料中分别提供的174 g, 156 g, 120 g,高产群、中产群、低产群每头每日实际需要量为235 g, 226 g, 200 g。[结论]通过高产奶牛自由舔食补饲小苏打的研究,确认自由舔舐是一种安全有效的小苏打补充方法。添加适合剂量的小苏打能够预防高产奶牛代谢性疾病的发生,有效减少奶牛恶性舔土现象,从而提高奶牛的生产和繁殖性能。     

The sequential appearance of sperm abnormalities after scrotal insulation or dexamethasone treatment in bulls.

Scrotal insulation and dexamethasone treatment were used as a model to compare the effect of testicular heating and stress on spermatogenesis. Insulation was applied to the scrotum of eight bulls (insulated) for a period of four days, eight bulls were treated daily for seven days with 20 mg dexamethasone injected intramuscularly, and four bulls were untreated controls. Semen from four bulls in each group was collected and evaluated over a six-week period after treatment. Blood samples for testosterone analysis were taken hourly for eight hours at the beginning and the end of the six-week period from the control bulls and before and after treatment from the four insulated and four dexamethasone-treated bulls that were not used for semen collection. At the end of the last blood sampling period, the four bulls in each group were castrated for the collection of testicular tissue for the determination of testosterone concentrations. Basal, peak episodic, and mean serum testosterone concentrations among control bulls, pre and postinsulated bulls, and pretreatment samples of dexamethasone-treated bulls were not different (p > 0.05); however, bulls that had received dexamethasone treatments had significantly lower basal, peak episodic, and mean testosterone concentrations (p < 0.05). Tissue concentrations of testosterone in control, insulated, and dexamethasone-treated bulls were not significantly different but tended to be lower in dexamethasone-treated bulls (p > 0.13). The spermiograms of the control bulls varied insignificantly over the six-week sampling period; however, there was a marked increase in sperm defects in insulated and dexamethasone-treated bulls. The types of sperm defects and the temporal relationships of rises and declines of sperm defects were quite similar for both treatments. All bulls recovered to approximately pretreatment levels of sperm defects by six weeks after the initiation of treatment. Results indicate that two of the most common types of insults to spermatogenesis in bulls, heat and stress, result in similar spermiograms.