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Background and Aim: The use of antimicrobials in the control of mastitis is of concern in public health due to their inefficiency in targeting microorganisms. Studies with medicinal plants have risen as an alternative to the use of conventional products. The objective of this study was to evaluate the efficacy of an experimental disinfectant based on the essential oil (EO) from Lippia origanoides in preventing the development of new intramammary infections (IMI) in Holstein cows. Materials and Methods: The conventional protocol of pre- and post-milking was used and the control (Conventional treatment [CNV]) and experimental (Experimental treatment [PEX]) products containing EO at 120 μL/mL were applied by immersion. Individual milk samples were analyzed using sheep blood agar methodologies and biochemical tests. The efficiency of the treatment was defined by the presence or absence of Staphylococcus aureus, coagulase-negative Staphylococcus, and Streptococcus spp. Results: There were no clinical and subclinical mastitis cases, no lesions in the mucosal of teats, nor dirt score between groups in this study. Both treatments did not influence the occurrence of IMI. Conclusion: The results revealed that PEX acts efficiently against microorganisms compared to the disinfection by the conventional product demonstrating the efficacy of the alternative product on the prevention of new IMIs in dairy cows.

MG 39404-547, Brazil. E-mail: aca2006@ica.ufmg.br This study evaluated the antimicrobial activity and acute or chronic toxicity of the extract of Stryphnodendron adstringens. The stem bark dry extract was obtained by static maceration with ethanol. Quantification of tannins was performed by the Folin-Denis method, which indicated a total tannin content of 32.7%. The antimicrobial activity of the dry extract of S. adstringens was evaluated by agar-based disk diffusion assay with Escherichia coli (ATCC 25922) and Staphylococcus aureus (ATCC 25923) in the concentration of 200, 400 and 600μL/mL. The results indicated that 600μL/mL inhibited microbial growth, i.e. had antimicrobial activity against these species. Acute and chronic toxic effects of S. adstringens was evaluated in Wistar rats treated with 200, 400, 600 and 800mg/kg of extract, administrated by gavage. Liver degeneration was observed in the group of rats receiving 800mg/kg in chronic exposure, what may indicate some degree of toxicity at this concentration. However, no systemic toxicity was observed at lower doses. Considering the broad use of S. adstringens as a phytotherapeutic agent for various human and animal diseases and the livertoxicity observed at high concentrations, attention should be paid to the possible adverse effect of using the extract from this plant at high concentration.

O presente estudo teve como objetivo avaliar a eficácia de um novo produto elaborado a base de óleo essencial de alecrim pimenta sob a redução da contagem de microrganismos presentes na pele de tetos de vacas leiteiras. Para o teste in vivo, avaliou-se a eficácia do novo produto sob a antissepsia de negativos para mastite clínica (192 tetos), em comparação ao tratamento que continha produtos comerciais (192 tetos), durante um período de 42 dias. Os tetos foram diariamente acompanhados clinicamente, havendo semanalmente avaliação da microbiota presente na pele dos mesmos quanto à redução na contagem de Staphylococcus aureus, Estafilococos coagulase negativo (ECN), Echerichia coli e aeróbios mesófilos. Os dois produtos mantiveram a integridade dos tetos, sendo observado ausência de mastite clínica durante o período experimental.  Não observou-se diferença significativa na ocorrência de mastite subclínica e de microrganismos nos tetos dos dois grupos em estudo pelo teste de Fisher em nível de significância de 5%. Ao comparar a redução Log da contagem em UFC.mL-1 dos microrganismos para o grupo tratado com produto convencional e com produto experimental para aeróbios mesófilos, E. coli, S. aureus e Estafilococos coagulase negativa, obtidos com o processo de higienização dos tetos foi observada diferença estatística(p>0,05), na contagem de microrganismos, evidenciando que ambos apresentaram efeito semelhante ao controle de microrganismos presentes na pele dos tetos. Sendo assim, o novo produto contendo óleo essencial de alecrim pimenta apresentou eficácia semelhante ao produto convencional clorexidine e iodo para antissepsia dos tetos de vacas leiteiras sem promover reações locais na pele, podendo este vir a ser utilizado como produto alternativo no manejo de ordenha.