Field evaluation of commercial vaccines against Infectious Bovine Rhinotracheitis (Ibr) Virus using different immunization protocols

Bovine alphaherpesvirus 1 is ubiquitous in cattle populations and is associated with several clinical syndromes, including respiratory disease, genital disease, infertility and abortions. Control of the virus in many parts of the world is achieved primarily through vaccination with either inactivated or live modified viral vaccines. The objective of this study was to evaluate the performance of four commercially available BoHV-1 vaccines commonly used in Central and South America. Animals were divided into eight groups and vaccinated on days 0 and 30. Groups 1 to 4 received two doses of four different BoHV-1 commercial vaccines (named A to D). Groups 5 and 6 received vaccine D plus a vaccine for either Clostridial or Food-and-Mouth-Disease (FMD), respectively. Group 7 received one dose of two different brands of reproductive vaccines. Serum samples were collected from all animals on days 0, 30 and 60 to evaluate neutralizing and isotype-specific (IgG1 and IgG2) antibodies. Of the four commercial vaccines evaluated, only vaccine A induced neutralizing antibodies to titers ≥ 1:8 in 13/15 (86%) of the animals 60 days post-vaccination. Levels of IgG2 antibody increased in all groups, except for group 2 after the first dose of vaccine B. These results show that only vaccine A induced significant and detectable levels of BoHV-1-neutralizing antibodies. The combination of vaccine D with Clostridial or FMD vaccines did not affect neutralizing antibody responses to BoHV-1. The antibody responses of three of the four commercial vaccines analyzed here were lower than admissible by vaccine A. These results may be from vaccination failure, but means to identify the immune signatures predictive of clinical protection against BoHV-1 in cattle should also be considered

Field Evaluation of Commercial Vaccines against Infectious Bovine Rhinotracheitis (Ibr) Virus Using Different Immunization Protocols

Bovine alphaherpesvirus 1 is ubiquitous in cattle populations and is associated with several clinical syndromes, including respiratory disease, genital disease, infertility and abortions. Control of the virus in many parts of the world is achieved primarily through vaccination with either inactivated or live modified viral vaccines. The objective of this study was to evaluate the performance of four commercially available BoHV-1 vaccines commonly used in Central and South America. Animals were divided into eight groups and vaccinated on days 0 and 30. Groups 1 to 4 received two doses of four different BoHV-1 commercial vaccines (named A to D). Groups 5 and 6 received vaccine D plus a vaccine for either Clostridial or Food-and-Mouth-Disease (FMD), respectively. Group 7 received one dose of two different brands of reproductive vaccines. Serum samples were collected from all animals on days 0, 30 and 60 to evaluate neutralizing and isotype-specific (IgG1 and IgG2) antibodies. Of the four commercial vaccines evaluated, only vaccine A induced neutralizing antibodies to titers ≥ 1:8 in 13/15 (86%) of the animals 60 days post-vaccination. Levels of IgG2 antibody increased in all groups, except for group 2 after the first dose of vaccine B. These results show that only vaccine A induced significant and detectable levels of BoHV-1-neutralizing antibodies. The combination of vaccine D with Clostridial or FMD vaccines did not affect neutralizing antibody responses to BoHV-1. The antibody responses of three of the four commercial vaccines analyzed here were lower than admissible by vaccine A. These results may be from vaccination failure, but means to identify the immune signatures predictive of clinical protection against BoHV-1 in cattle should also be considered

Arroz irrigado: Sistema de produção Clearfield - Manejo da lavoura para semeadura em pré-germinado e em solo seco

Esta publicação reúne recomendações técnicas da Epagri para a condução de lavouras de arroz irrigado no Sistema de Produção Clearfield. O Sistema de Produção Clearfield (CL) é destinado, principalmente, para áreas infestadas com arroz-daninho (também conhecido como arroz-vermelho) e demais plantas daninhas que infestam as lavouras de arroz irrigado de Santa Catarina. O Sistema CL de produção de arroz possui três componentes principais: uso de variedades resistentes aos herbicidas do grupo químico das imidazolinonas, uso de herbicidas registrados e recomendados para o sistema e um programa de monitoramento da lavoura que visa impedir a evolução de resistência das plantas daninhas a esses herbicidas. Atualmente, a Epagri disponibiliza os cultivares SCS117 CL (de primeira geração) e SCS121 CL (de segunda geração, lançado em 2015). Como os cultivares de segunda geração apresentam nível mais alto de resistência aos herbicidas recomendados, o cultivar SCS121 CL deve ser utilizado preferencialmente no sistema CL.Em lavouras semeadas com solo drenado, ocorre geralmente elevada infestação de arroz-daninho. O Sistema Clearfield, diferentemente dos sistemas tradicionais, permite que essa planta daninha seja controlada de forma eficaz. No sistema de semeadura em solo seco, o preparo antecipado do solo com cultivo mínimo é uma estratégia fundamental para reduzir o risco de evolução da  resistência das plantas daninhas aos herbicidas. Outra importante estratégia  recomendada é a rotação dos sistemas de cultivo “pré-germinado” e “cultivo mínimo” como forma de reduzir os danos causados por pragas, doenças e plantas daninhas. A observância dos fundamentos de sustentação do sistema de produção Clearfield, o uso de semente certificadas, o emprego de herbicidas registrados e recomendados para o sistema CL e a adoção do programa de monitoramento da  lavoura são ações que possibilitam manter a longevidade desse sistema de produção de arroz.