Effects of dietary molybdenum on nematode and host during Haemonchus contortus infection in lambs.

The addition of molybdenum (0.05 mmol kg-1 dry-matter) to the diet of lambs given a trickle infection of Haemonchus contortus larvae (500 third stage larvae d-1 over six weeks) reduced mean faecal egg counts (epg) from 3952 to 2312 +/- 402 by 32 days (P less than 0.02) and greatly reduced the mean number of worms recovered from the abomasum 14 days after infection ceased (907 compared with 4167: P less than 0.01). Infection reduced haemoglobin concentrations less in lambs given molybdenum although the difference was small relative to the reduction in worm burden. Lambs not given molybdenum had low intraepithelial mast cell counts in the abomasal mucosa and less abomasal hypertrophy than expected from abomasal parasitism. Molybdenum did not consistently reduce the copper status of the host or the parasite. Previous exposure to molybdenum greatly reduced protein but not proteinase activity in, or secreted by, adult worms cultured for eight hours. It is suggested that molybdenum either increased the inflammatory response which preceded worm rejection or that it indirectly enhanced that reaction by reducing the effectiveness of copper-dependent, anti-inflammatory enzymes in the gastrointestinal mucosa.     

泌乳母猪的饲喂:科学和实践的结合

在星际旅行的时代 ,我们怎么能还在争辩怎样饲喂泌乳母猪的问题呢 ?如果我们能够破解动物的遗传编码 ,我们为什么不能理解采食量和泌乳母猪性能之间的相互关系呢 ?但是 ,也许我们确实理解了这些关系 ,不过我们不能将科学转化为良好的猪场实践。也许我们过分地试图将一般原则或指南应用于非常具有个性的具体场合之中 ,无论这些具体场合是指不同的猪种、不同的猪场或者不同的个体。每一头泌乳母猪都是独特的 ,将一般原则应用于独特的动物 ,一般来说结果都是不太令人满意的。但是 ,随着猪场规模的扩大 ,可能就越来越难以将每一头母猪都进行个别…     

Feline leukemia virus detection by immunohistochemistry and polymerase chain reaction in formalin-fixed, paraffin-embedded tumor tissue from cats with lymphosarcoma.

The prevalence of feline leukemia virus (FeLV) antigen and DNA was assessed in formalin-fixed, paraffin-embedded tumor tissues from 70 cats with lymphosarcoma (LSA). Tissue sections were tested for FeLV gp70 antigen using avidinbiotin complex (ABC) immunohistochemistry (IHC); DNA was extracted and purified from the same tissue blocks for polymerase chain reaction (PCR) amplification of a 166 base pair region of the FeLV long terminal repeat (LTR). Results were related to antemortem FeLV enzyme-linked immunosorbent assay (ELISA) for serum p27 antigen, anatomic site of LSA, and patient age. Viral DNA was detected by PCR in 80% of cases and viral antigen by IHC in 57% of cases. Seventeen cases were PCR-positive and IHC-negative; one case was PCR-negative and IHC-positive. Clinical records included FeLV ELISA results for 30 of 70 cats. All 19 ELISA-positive cats were positive by PCR and IHC; of the 11 ELISA-negative cats that were negative by IHC, seven were positive by PCR. When evaluated according to anatomic site, FeLV DNA and antigen were detected less frequently in intestinal LSAs than in multicentric and mediastinal tumors. Lymphosarcoma tissues from cats < 7 yr were several fold more likely to be positive for FeLV antigen by IHC than were tumors from cats > or = 7 yr. However, there was no significant difference in PCR detection of FeLV provirus between LSAs from cats < 7 yr and those > or = 7 yr.(ABSTRACT TRUNCATED AT 250 WORDS)     

提高繁殖猪群效率纵横谈

繁殖猪群的目标是不断地以低成本生产计划数量的优质断奶仔猪。图 1显示了影响断奶仔猪产量的因素。断奶仔猪产量是繁殖群母猪存栏数 (能力 )与每头母猪年产断奶仔猪数 (效率 )的乘积。确定繁殖猪群的适当大小而使其适合于养猪设施的容量 ,同时确定后备母猪群的适当大小而使其适合于每周的配种计划 ,是为实现断奶仔猪产量计划和充分利用产仔栏所必需的。一般来说 ,是否适合于配种计划和分娩率 ,是影响每头存栏母猪年产断奶仔猪数量的最重要的因素(表 1 )。图 1　影响断奶仔猪产量的各种因素之间的相互关系　表 1　每周断奶仔猪产量影响因素…     

一种新的赖氨酸源

猪、禽日粮的传统赖氨酸添加源是盐酸Ｌ 赖氨酸。但是 ,如今有了另一种赖氨酸源 ,这种新赖氨酸源在经济上可比传统的盐酸Ｌ 赖氨酸更为合算。这种新赖氨酸源是一种干燥的颗粒状产品 ,其中含硫酸Ｌ 赖氨酸和发酵副产品 ,由谷氨酸棒状杆菌(Ｃｏｒｙｎｅｂａｃｔｅｒｉｕｍｇｌｕｔａｍｉｃｕｍ)发酵产生 ,产地为美国内布拉斯加州。其商品成品提供 60 %盐酸Ｌ 赖氨酸的赖氨酸替代值。此外 ,其发酵副产品还含有盐酸Ｌ 赖氨酸中不含的其它氨基酸、磷和能量 (表 1 )。美国已用猪和肉鸡对其进行了硫酸Ｌ 赖氨酸和盐酸Ｌ 赖氨酸的比较试验。最近在美…     

Isolation of oxfendazole resistant Cooperia oncophora in cattle

A field strain of Cooperia oncophora resistant to oxfendazole was isolated from a commercial cattle rearing property in Waikato, New Zealand. Resistance to oxfendazole was assessed by means of a faecal egg count depression test and an in vitro egg hatch test. This is the first documented case of anthelmintic resistance in Cooperia spp. and the first report of anthelmintic resistance in cattle in New Zealand.     

Book reviews

Recent Advances in Turkey Science. Edited by C. Nixey and T. C. Grey, Poultry Science Symposium Number 21. London, Butterworths, ISBN 0 408 00971 3

Egg and Eggshell Quality. Sally E. Solomon, 1991, 149 pp., illustrated. London, Wolfe Publishing Ltd., £35.00, ISBN 0 7234 1647 8.

Aleen Cust, Veterinary Surgeon, Britain's First Woman Vet. Connie M. Ford, 1990, 109 pp., £5.99, Bristol, Biopress Ltd., The Orchard, Clanage Road, ISBN 0 948737 11 5.

Avian Incubation. Edited by S. G. Tullett, 1991, xiv + 335 pp., illustrated. London, Butterworth‐Heinemann. £00.00, $00.00. ISBN 0–7506–1002–6.

A Colour Atlas of Diseases & Disorders of the Domestic Fowl & Turkey. Edited by C. J. Randall, second edition, 1991, 175 pages, 432 illustrations in colour. London, Wolfe Publishing Ltd, £35, ISBN 0723416281.     

A perspective on ovine footrot control

A method for the control of ovine footrot is described which utilises the most appropriate measures to suit the circumstances for individual properties. This approach was used to eradicate the disease from three Central Otago fine-wool properties wintering in excess of 35,000 sheep on widely differing classes of land. This programme incorporates the use of proven.techniques and suitable planning together with input from the rural veterinarian, who plays an important role in demonstration and advising on control measures.     

Isolation of avian influenza virus (subtype H5N2) from chicken eggs during a natural outbreak

Avian influenza virus (A/Chicken/Pennsylvania/83; H5N2) was recovered from the yolk, albumen, and shell surface of eggs obtained from naturally infected chicken flocks in Pennsylvania and Virginia. These findings represent the first reported isolation of avian influenza virus from the internal contents of eggs from naturally infected flocks. The need for adequate safeguards to prevent spread of the virus during commercial movement of table and hatching eggs, cracked and "checked" eggs, and egg flats and other materials is emphasized.