Prevalence of four enteropathogens in the faeces of young diarrhoeic dairy calves in Switzerland

The prevalences of Cryptosporidium parvum, rotavirus, bovine coronavirus (bcv), and enterotoxigenic Escherichia coli (E coli k99) were determined in diarrhoeic dairy calves aged one to 21 days on 71 dairy farms in western Switzerland during the winter of 2005 to 2006. Faecal samples from 147 untreated calves suffering from acute diarrhoea were analysed by standardised diagnostic methods, and the immunoglobulin status of each calf was evaluated. The prevalences of C parvum, rotavirus, bcv and E coli k99 were 55.0 per cent, 58.7 per cent, 7.8 per cent and 5.5 per cent, respectively. The proportions of herds positive for the respective pathogens among the herds with diarrhoeic calves were 41.7 per cent, 52.1 per cent, 2.1 per cent and 2.1 per cent. The immunoglobulin concentration in the serum of 90.5 per cent of the diarrhoeic calves was below 8 g/l.     

玉米F_2群体中偏分离RFLP标记在染色体上的分布及原因分析

研究了利用玉米85个 DNA 限制性片段长度多态性(RFLP)标记在玉米自交系7922与5003杂交 F2群体中的分离。结果表明,8.33%的标记显著或极显著地偏离了预期的孟德尔比例而表现偏分离,发现了2个偏分离的染色体热点,即第1染色体上的 umc128-umc107和第3染色体上的 asg24-asg48,其偏分离形成的主要原因是存在配子体选择。     

Serum and Tissue Steroid Hormone Levels in Canine Mammary Tumours: Clinical and Prognostic Implications

Hormonal dependency of canine mammary tumours (CMT) has been studied over the last few decades. However, studies assessing the prognostic and predictive potential of serum and/or tissue steroid hormone levels are still scarce in CMT. To the best of our knowledge, this is the first report relating serum and tissue levels of steroid hormones and prognosis in dogs. Serum and tumour tissue from 45 female dogs with spontaneous CMT were included in the study. Moreover, serum and normal mammary tissue from 13 healthy female dogs were also included as controls. Steroid hormones were determined by competitive enzyme immunoassay. Overall, levels of steroid hormones in serum and tissue homogenates were significantly different between malignant and benign mammary tumours (p < 0.01), except for progesterone (P4) serum levels that revealed no statistical differences between groups. In malignant tumours, oestrone sulphate (SO4E1), dehydroepiandrosterone (DHEA), androstenedione (A4), testosterone (T) and P4 elevated tissue concentrations were significantly associated with tumour relapse and/or distant metastasis during follow‐up. A significant association was found between elevated tissue SO4E1 (p = 0.003), 17β‐oestradiol (E2) (p = 0.036), DHEA (p = 0.022), A4 (p = 0.001) and P4 (p = 0.013) concentrations and shorter disease‐free survival and overall survival in female dogs with malignant mammary tumours. The high levels of tissue steroids found in cases of poor prognosis open the possibility of additional new therapeutic approaches. Future clinical trials will be needed to clarify the usefulness of targeting steroid hormones in the treatment of this neoplastic disease.     

Floral resource partitioning by ants and bees in a jambolan Syzygium jambolanum (Myrtaceae) agroforestry system in Brazilian Meridional Amazon

The fruit production of flowering plants critically depends on the pollination services provided by animals that compete for flower resources. The output of competitive interactions between ants and bees for inflorescences of jambolan Syzygium jambolanum (Myrtaceae) in an agroforestry system in Brazilian Meridional Amazonian are an interesting system of investigation due the possibility to control variables experimentally. In 20 S. jambolanum individuals we performed 300 treatments in different inflorescences of two strata (upper and lower) as follows: (1) ants exclusion, (2) bees exclusion, and (3) control group where ants and bees could access the inflorescences. There was no difference in the number of inflorescences, volume of nectar and sugar concentration between the strata. Also the visitors considered are distributed equally in the tree??s stratum. When bees were prevented from access the inflorescences, ants dominated more inflorescences only in the lower stratum. On the contrary, when ants were excluded, bees visited more inflorescences only in the upper stratum. We conclude that ants prevent the access to bees and vice versa as the result of different ability of resource utilization and foraging strategies. Thus, preventing the access of ants to the floral nectar could increase the level of nectar available to pollinators of S. jambolanum, thereby increasing productivity and reducing economic losses.     

Solid‐Surface Vitrification and In‐Straw Dilution After Warming of In Vitro‐Produced Bovine Embryos

Three experiments were designed to test a solid‐surface vitrification system for bovine in vitro‐produced embryos and to develop a simple method of in‐straw dilution after warming, which can be potentially used for direct transfer in the field. Experiment 1 evaluated embryo survival rates (i.e. re‐expansion and hatching) after vitrification and warming in three different solutions: VS1 (20% ethylene glycol (EG) + 20% propanediol (PROH) + 0.25 m trehalose (Tr)), VS2 (20% EG + 1M Tr) or VS3 (30% EG + 0.75 m Tr). Re‐expansion and hatching rates were higher (p < 0.05) for embryos vitrified in VS3 (72.2 ± 1.9 and 58.2 ± 0.8) than VS1 (64.4 ± 0.9 and 37.2 ± 2.5) or VS2 (68.5 ± 1.5 and 49.6 ± 1.0; p < 0.05). Experiment 2 was designed to compare two methods of vitrification: glass micropipettes or solid surface, using the VS1 or VS3 solutions. No significant differences were detected between the two methods; but re‐expansion and hatching rates were higher (p < 0.05) with VS3 (73.5 ± 3.1 and 47.1 ± 2.1) than VS1 (63.3 ± 3.3 and 39.7 ± 2.8). In experiment 3, embryos were vitrified by solid surface in VS1 or VS3 solutions and cryoprotectants were diluted in‐straw after warming in a TCM 199, 0.25 m sucrose solution or holding media. Survival rates of embryos vitrified in VS3 did not differ between those exposed to 0.25 m sucrose (74.7 ± 1.3 and 57.2 ± 2.2) or holding (77.3 ± 1.4 and 58.0 ± 2.5) medium after warming; however, survival rates of embryos vitrified in VS1 were higher (p < 0.05) in those exposed to 0.25 m sucrose (67.7 ± 2.3 and 47.0 ± 1.7) than holding medium (54.5 ± 1.0 and 27.7 ± 3.1). In conclusion, solid‐surface vitrification using simplified EG‐based solutions and in‐straw dilution with holding media may be a practical alternative for cryopreservation and direct transfer of in vitro‐produced bovine embryos.     

治疗奶牛乳腺炎的新药盐酸吡利霉素研究进展

综述了治疗奶牛乳腺炎的新药——盐酸吡利霉素最新研究进展.对其基本药学性质、药动、药效、毒性和残留等多方面进行了详细阐述.     

磷酸泰乐菌素颗粒剂生物效价测定方法的建立及验证

建立了磷酸泰乐菌素颗粒剂的生物效价测定方法，并对新建立的测定方法进行了验证，验证内容包括：方法对照试验、精密度试验、线性及线性范围试验、回收率试验。验证结果证明新方法能准确测定磷酸泰乐菌素颗粒剂的效价单位。