Effects of zeranol implants on post-castration response in calves

SUMMARY Suckling and yearling calves were surgically castrated and one half of each group implanted with 36 mg zeranol at time of castration. Both treated and control cattle of each class were maintained as a group and evaluated for swelling of the scrotum, inflammation and healing, plasma prostaglandin levels and weight gain. Swelling and inflammation of the scrotum were less in treated suckling calves than in controls at both 7 and 14 d after castration, though this difference was not statistically significant. In yearlings at 7 d after castration, treated cattle had more swelling than controls; however at 14 d, treated cattle had less swelling and inflammation with only one treated yearling having an open scrotal wound versus 6 (P <.03) in the control group. Plasma prostaglandin levels as indicated by plasma malondialdehyde increased from d 0 to 14; however no significant treatment differences were observed for either age group. Suckling calves treated with zeranol gained 9.79 kg more (P <.03) than non-treated calves during the 97 d of trial while the yearlings treated with zeranol gained 16.78 kg more (P <.01) than controls during 102 d. It is concluded from the increased growth and reduced scrotal swelling and inflammation in treated cattle that zeranol implantation could possibly have a beneficial effect in improving the healing process after castration.     

A sandwich enzyme immunoassay for bovine interferon-γ and its use for the detection of tuberculosis in cattle

An in vitro cellular assay for bovine tuberculosis has recently been developed. This assay detects gamma-interferon released in response to specific antigen in a whole blood culture system. The bio-assay previously described for the detection of bovine gamma-interferon (IFN-gamma) has now been replaced with a sandwich enzyme immunoassay (EIA) which utilises two monoclonal antibodies to bovine IFN-gamma. The EIA detects less than 25pg/ml of recombinant bovine IFN-gamma and is specific for biologically active bovine IFN-gamma; and does not detect bovine alpha or beta interferon. IFN-gamma from sheep, goat and buffalo, but not from pig, deer or man, are also recognised by the EIA. The bovine IFN-gamma EIA when used in conjunction with the whole blood culture system has resulted in a simple, rapid and sensitive in vitro assay for specific cell mediated immune responsiveness to M. bovis infection in cattle.     

Metocurine pharmacokinetics and pharmacodynamics in goats

Non-depolarizing muscle relaxants can facilitate surgery and anaesthesia in numerous species, and volatile inhalational anaesthetics such as isoflurane potentiate their action. We studied the effect of isoflurane on the pharmacodynamics and pharmacokinetics of metocurine in six goats. Each was studied twice: once during barbiturate-opiate anaesthesia and once during isoflurane anaesthesia. The evoked response to sciatic nerve stimulation was measured using a force transducer attached to the hoof. Metocurine was infused until approximately 80–90% blockade. Plasma metocurine concentration was determined by high-performance liquid chromatography. Isoflurane increased the potency of metocurine significantly; IC₅₀ (the concentration in the effect compartment at 50% paralysis) was 70 ± 15 ng/mL during isoflurane anaesthesia and 129 ± 42 ng/mL during barbiturate-opiate anaesthesia ( P < 0.03). Volume of distribution (63 ± 18 mL/kg), clearance (1.6 ± 0.4 mL/min±kg) and elimination half-life (99 ± 9 min) during barbiturate-opiate anaesthesia were not significantly different during isoflurane anaesthesia: 64 ± 25 mL/kg, 1.5 ± 0.7 mL/kgmin, 116 ± 16 min respectively. We conclude that, relative to barbiturate-opiate anaesthesia, isoflurane potentiates metocurine in goats.     

Efficiency of inspection procedures for the detection of tuberculous lesions in cattle

The sensitivity of the abattoir inspection procedure introduced for Australian export beef in 1976 was compared to a detailed necropsy procedure for the detection of tuberculous lesions in cattle. In a sample of cattle that were reactors to the tuberculin test, abattoir inspection failed to detect an estimated 47% of cattle with lesions. The detailed necropsy examination of cattle with lesions of tuberculosis identified 21 sites of infection compared with 13 to 18 in cattle examined by routine meat inspection procedures. Of the lesions detected during detailed necropsy, 15.9% did not involve the thoracic cavity or the medial retropharyngeal lymph nodes. The failure to detect lesions during abattoir inspection has its greatest significance in an animal with a single lesion. If the 245 cattle found with single lesions during detailed necropsy had been examined by abattoir inspection using the 1976 or the 1986 procedures, 0.8 and 8.9%, respectively, of these animals would not have been detected because the diseased tissues would not have been examined. If meat inspection is to provide an effective means of monitoring the level of bovine tuberculosis during the final stages of eradication, a procedure no less sensitive than that introduced in 1976 should be used.     

大豆遗传资源保护的法律法规及其可专利性

大豆起源于中国,中国是世界上大豆遗传资源最为丰富的国家,也曾经是世界上最主要的大豆生产国和出口国。半个多世纪以来,科学技术的进步带动了一些美洲国家大豆产业的迅猛发展,中国的大豆生产量由世界首位降到美国、巴西之后,从大豆出口国变为大豆净进口国,大豆成为中国农产品贸易中最令国际社会关心的贸易作物。随着农业生物技术的快速发展,知识产权保护的法律法规的国际化,尤其是我国加入WTO以后,大豆研究、开发、生产领域遇到了来自比其他作物前所未有的挑战。作为我国最重要的植物蛋白、食用油及动物饲料来源的大豆作物,有效地利用有关的法律法规保护我国大豆种质资源及新品种已经迫在眉睫。本文着重介绍了与大豆遗传资源、新品种保护相关的我国法律法规,进行了大豆保护的可专利性分析,并对大豆研发过程中的知识产权保护问题作了初步探讨,以促进对大豆新品种的申请保护,提高我国应对来自国外竞争的抗衡能力。     

A comparison of the effects of the nematodes Radopholus similis and Pratylenchus goodeyi on growth,root health and yield of an East African highland cooking banana (Musa AAA-group)

We combined two protein-marking enzyme-linked immunosorbent assays (ELISA) with a predator gut content ELISA to monitor the movement and feeding activity of commercially-purchased Hippodamia convergens Guèrin-Mèneville (Coleoptera: Coccinellidae) under realistic field conditions during two field seasons in central Arizona. The protein-marking ELISAs were used to differentiate released H. convergens from the native beetles. Commercially purchased beetles marked with rabbit immunoglobulin G (IgG) were released into cotton fields and chicken IgG marked beetles were released into adjacent cantaloupe fields. Results showed that the total native beetle abundance in each crop was about the same size. The recovery rates after 15 days for the released beetles were less than 1.0% over all the releases, indicating that they dispersed readily from the release site. Of the recaptured beetles containing rabbit IgG (cotton), 82.2% were recovered in cotton and 11.8% moved to cantaloupe. Of those containing chicken IgG (cantaloupe), 66.5% were recovered in cantaloupe and 33.5% moved to cotton. A predator gut content ELISA was used to determine if there were differences in the frequency of predation of released versus indigenous H. convergens on the silverleaf whitefly, Bemisia argentifolii Bellows &; Perring (Homoptera: Aleyrodidae). The proportion of beetles containing whitefly antigens was always higher for the released beetles than for their native counterparts. Our results demonstrate an approach to combine protein marking and predator gut content ELISAs that allows the simultaneous comparison of feeding and intercrop movement of native and commercially-obtained biological control agents.