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Efeito da utilização de escovas mecânicas nas rotinas de pré-ordenha na contagem bacteriana da pele dos tetos
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As mastites representam uma das principais causas de perdas económicas nas explorações leiteiras, sendo a sua prevenção importante na saúde do úbere e na qualidade do leite. A higienização dos tetos antes da ordenha constitui uma medida central no seu controlo, tendo a introdução de escovas mecânicas para limpeza dos tetos surgido como uma alternativa automatizada e uniformizadora às rotinas convencionais. Este sistema combina a fricção rotativa das escovas com a aplicação de desinfetante, seguida da secagem dos tetos. A presente dissertação teve como objetivo principal avaliar a eficácia das escovas mecânicas na redução da carga bacteriana da pele dos tetos. O estudo foi realizado em três explorações leiteiras com protocolos de higienização distintos. Nas explorações A e B a preparação dos tetos incluía um pre-dipping com desinfetante à base de iodo antes da utilização das escovas mecânicas, enquanto na exploração C a higienização era feita exclusivamente com escovas. Em cada exploração foram amostrados os tetos de 20 vacas em lactação através da realização de zaragatoas cutâneas antes e após a higienização (realizada por diferentes ordenhadores). Os animais foram divididos em dois grupos: grupo Teste (submetido ao protocolo habitual da exploração) e grupo Controlo (com aplicação de desinfetante à base de iodo e secagem manual). As contagens bacterianas foram realizadas em Trypticase Soy Agar (contagem total) e agar de MacConkey (enterobactérias), com avaliação da redução logarítmica das unidades formadoras de colónias por mililitro (UFC/mL) após 48 horas de incubação a 37 ºC. Verificou-se uma redução significativa da carga bacteriana em todos os grupos, independentemente do protocolo ou exploração. No entanto, apenas na exploração A (para ambos os indicadores microbiológicos) e na exploração B (para enterobactérias) a utilização das escovas mecânicas demonstrou uma eficácia significativamente superior à do protocolo convencional. Não foram detetadas diferenças estatisticamente significativas na eficácia de higienização com escovas entre os diferentes ordenhadores de cada exploração, apesar de não se verificar uma maior homogeneidade dos resultados em relação ao protocolo convencional. Os resultados obtidos sugerem que a combinação de pre-dipping com a utilização das escovas mecânicas potencia a sua eficácia, não se identificando diferenças significativas entre os dois métodos quando utilizados de forma isolada. A elevada variabilidade operacional entre as explorações avaliadas sublinha a necessidade de estudos adicionais, com maior dimensão amostral e inclusão de outras variáveis, de modo a consolidar a evidência científica relativamente a esta tecnologia
Mastitis remains one of the main causes of economic losses in dairy farming, with its prevention being essential for udder health and milk quality. Teat cleaning prior to milking plays a central role in mastitis control, and the introduction of mechanical brushes for teat cleaning has emerged as an automated and standardizing alternative to conventional routines. This system combines the rotating friction of the brushes with the application of disinfectant, followed by teat drying. The main objective of this dissertation was to evaluate the efficacy of mechanical brushes in reducing the bacterial load on teat skin. The study was conducted in three dairy farms with distinct hygiene protocols. In farms A and B, teat preparation included a pre-dipping with iodine-based disinfectant before the use of mechanical brushes, whereas in farm C the cleaning was performed exclusively using brushes. On each farm, teats from 20 lactating cows were sampled by cutaneous swabbing before and after hygiene procedures (performed by different milkers). Animals were divided into two groups: the Test group (subjected to the farm’s usual protocol) and the Control group (treated with iodine-based disinfectant and manual drying). Bacterial counts were performed using Trypticase Soy Agar (total count) and MacConkey agar (enterobacteria), with evaluation of the logarithmic reduction in colony forming units per millilitre (CFU/mL) after 48 hours of incubation at 37 °C. A significant reduction in bacterial load was observed in all groups, regardless of the protocol or farm. However, only in Farm A (for both microbiological indicators) and in Farm B (for enterobacteria) did the use of mechanical scrubbers show significantly higher efficacy than the conventional protocol. No statistically significant differences were found in hygiene efficacy among the different milkers within each farm when using scrubbers, although no greater homogeneity of results was observed compared to the conventional method. The results suggest that combining pre dipping with the use of mechanical scrubbers enhances their efficacy, whereas no significant differences were identified between the two methods when used independently. The high operational variability among the evaluated farms highlights the need for further studies, with larger sample sizes and inclusion of additional variables, in order to consolidate the scientific evidence regarding this technology
Mastitis remains one of the main causes of economic losses in dairy farming, with its prevention being essential for udder health and milk quality. Teat cleaning prior to milking plays a central role in mastitis control, and the introduction of mechanical brushes for teat cleaning has emerged as an automated and standardizing alternative to conventional routines. This system combines the rotating friction of the brushes with the application of disinfectant, followed by teat drying. The main objective of this dissertation was to evaluate the efficacy of mechanical brushes in reducing the bacterial load on teat skin. The study was conducted in three dairy farms with distinct hygiene protocols. In farms A and B, teat preparation included a pre-dipping with iodine-based disinfectant before the use of mechanical brushes, whereas in farm C the cleaning was performed exclusively using brushes. On each farm, teats from 20 lactating cows were sampled by cutaneous swabbing before and after hygiene procedures (performed by different milkers). Animals were divided into two groups: the Test group (subjected to the farm’s usual protocol) and the Control group (treated with iodine-based disinfectant and manual drying). Bacterial counts were performed using Trypticase Soy Agar (total count) and MacConkey agar (enterobacteria), with evaluation of the logarithmic reduction in colony forming units per millilitre (CFU/mL) after 48 hours of incubation at 37 °C. A significant reduction in bacterial load was observed in all groups, regardless of the protocol or farm. However, only in Farm A (for both microbiological indicators) and in Farm B (for enterobacteria) did the use of mechanical scrubbers show significantly higher efficacy than the conventional protocol. No statistically significant differences were found in hygiene efficacy among the different milkers within each farm when using scrubbers, although no greater homogeneity of results was observed compared to the conventional method. The results suggest that combining pre dipping with the use of mechanical scrubbers enhances their efficacy, whereas no significant differences were identified between the two methods when used independently. The high operational variability among the evaluated farms highlights the need for further studies, with larger sample sizes and inclusion of additional variables, in order to consolidate the scientific evidence regarding this technology
Descrição
Dissertação de Mestrado Integrado em Medicina Veterinária, área científica de Produção Animal e Segurança Alimentar
Palavras-chave
Tetos Ordenha Higiene do Leite Desinfeção Contagem Bacteriana Teats Milking Dairy Hygiene Disinfection Bacterial Counting