We investigated the importance of SNP weighting in populations with 2,000 to 25,000 genotyped animals. Populations were simulated with two effective sizes (20 or 100) and three numbers of QTL (10, 50 or 500). Pedigree information was available for six generations; phenotypes were recorded for the four middle generations. Animals from the last three generations were genotyped for 45,000 SNP. Single-step genomic BLUP (ssGBLUP) and weighted ssGBLUP (WssGBLUP) were used to estimate genomic EBV using a genomic relationship matrix (G). The WssGBLUP performed better in small genotyped populations; however, any advantage for WssGBLUP was reduced or eliminated when more animals were genotyped. WssGBLUP had greater resolution for genome-wide association (GWA) as did increasing the number of genotyped animals. For few QTL, accuracy was greater for WssGBLUP than ssGBLUP; however, for many QTL, accuracy was the same for both methods. The largest genotyped set was used to assess the dimensionality of genomic information (number of effective SNP). The number of effective SNP was considerably less in weighted G than in unweighted G. Once the number of independent SNP is well represented in the genotyped population, the impact of SNP weighting becomes less important.

ResumoA região norte de Minas Gerais caracteriza-se por ser uma entre as regiões do país que têm o leite como um dos principais geradores de renda pela agricultura familiar. Para que o leite produzido tenha competitividade no mercado e tenha maior valor agregado, a agricultura familiar deve se adequar para atender os parâmetros legais vigentes. Teve-se como objetivo caracterizar o manejo produtivo geral adotado em unidades agrícolas familiares nos municípios de Bocaiúva, Francisco Sá e Montes Claros, no norte de Minas Gerais, identificando os entraves para a produção de leite dentro dos parâmetros estabelecidos pela legislação vigente. O sistema de produção foi avaliado por meio de coleta de dados em questionários e listas de verificação nos diferentes ambientes envolvidos com a produção. A qualidade microbiológica foi avaliada através da enumeração de microrganismos indicadores aeróbios mesófilos, psicrotróficos, Staphylococcus sp e coliformes fecais em leite cru, leite cru refrigerado, água e utensílios utilizados para produção. Os resultados da análise microbiológica associada às práticas de manejo adotadas revelaram que a principal causa da contaminação do leite era o emprego inadequado ou a ausência de boas práticas de higiene no sistema de produção, sendo este o principal entrave ao atendimento das exigências legais para o produto. Palavras-chave: Boas Práticas Agropecuárias; Contaminação; Qualidade do leite. AbstractThe northern region of Minas Gerais State is characterized as one of the regions of the country where milk has an important economic and social role for the family farming sector. Due to legal requirements, this sector must adjust so that the product will be marketed without bringing risk to the consumers, being, therefore, competitive on the commercial market. The objective of this study was to characterize the productive management generally adopted by the family farms in the municipalities of Bocaiuva, Capitão Enéas, Francisco Sá, and Montes Claros, in northern Minas Gerais, identifying the barriers to the production of milk within the parameters established by the legislation. The production system was evaluated by collecting data from questionnaires and checklists in the different environments involved with the production. The microbiological quality was assessed by enumeration of indicator microorganisms in aerobic mesophiles, psychrotrophic, Staphylococcus

Objetivou-se verificar a contaminação do leite cru por micro-organismos mesófilos, psicrotróficos, coliformes a 45°C e Enterococcus spp., produzido por rebanhos mestiços, em 30 unidades agrícolas familiares produtoras de leite em Juramento e Montes Claros, na região Norte de Minas gerais. Houve quatro coletas de amostras durante um ano, sendo duas na época de chuva e duas na época da seca. Coletaram-se amostras de leite cru e cru refrigerado, observando-se a contagem total de micro-organismos mesófilos, psicrotróficos, Enterococcus spp. e a contagem de coliformes a 45°C. Coletaram-se também, amostras de Swabs de equipamentos utilizados em ordenha (baldes e latões) utilizando-se a técnica do esfregaço em superfície, a fim de avaliar a contagem total bacteriana presente nesses utensílios para verificar a sua higienização. As amostras de leite apresentaram contaminação elevada por micro-organismos aeróbios mesófilos, psicrotróficos, Enterococcus spp.,coliformes a 45°C, comprometendo a qualidade higiênico-sanitária do produto, bem como as amostras de Swabs, que apresentaram níveis de contaminação elevados, quanto à presença de aeróbios mesófilos. Existiu deficiência quanto às práticas de antissepsias adotadas nos equipamentos utilizados na ordenha, levando a contaminações acima do permitido por mesófilos aeróbios, tornando-se evidente a necessidade de adoção de boas práticas agropecuárias e maiores investimentos em treinamentos e assistência técnica de qualidade com o intuito de provocar melhorias na qualidade microbiológica do leite produzido nessa região.

Milk production in the middle region of northern Minas Gerais state is the lowest in the state. However we noticed a considerable growth in recent years. It is important to conduct socioeconomic and generators technicians guiding information for the adoption of policy measures to boost production diagnostics. The aim of this study was to diagnose the production of milk in 30 family dairy farms in Juramento (15) and Montes Claros (15) city, Northern Minas Gerais; by a case study, semi-structured questionnaires that included information about general and sanitary handling, socioeconomic characteristics and also surveyed the use of agro-ecological practices in milk production. A systemic approach was used in the application of questionnaires. Out of the 30 properties, 86% have the dairy activity as the main one, followed by 14% of mixed activities. They have low to average technology and most farmers have another source of income in addition to milk production. The absence of agro-ecological practices in the production process was observed in 100% of the properties. It was concluded that milk production in family farms is very widespread, and the main characteristics are of properties with general and sanitary handling problems; the socioeconomic characteristics are of families with low to average income and dependent on the milk production to complement it. Regarding the agro-ecological practices, it can be concluded that they were rarely used in the properties surveyed.

ResumoO objetivo deste trabalho foi avaliar a atividade antimicrobiana in vitro do óleo essencial do Lippia sidoides (OELs), conhecido popularmente como "alecrim-pimenta", e do extrato bruto seco do Stryphnodendron adstringens (EBSSa), ou "barbatimão", contra bactérias isoladas do leite total de rebanho, provenientes de unidades agrícolas familiares do norte de Minas Gerais. O EBSSa foi obtido a partir da casca do vegetal por extração estática em etanol 99,9% por oito dias. O OELs foi obtido por meio da hidrodestilação das folhas frescas. As bactérias Escherichia coli e Staphylococcus aureus isoladas de leite foram submetidas aos testes de disco-difusão e concentração bactericida minima (CBM), utilizando as concentrações de 320, 160, 80, 40, 20 e 0μl/mL do OELs e 400, 200, 100, 50, 25 e 0mg/mL do EBSSa. Todas as bactérias se mostraram sensíveis aos extratos vegetais, exceto Escherichia coli que não foi inibida pelos dois testes quando foi utilizado o EBSSa. Palavras-chave: CBM, Coliformes, Lippia sidoides, Plantas medicinais, Stryphnodendron adstringens AbstractAntimicrobial activity of rosemary-pepper essential oil and barbatimao dry crude extract against bacteria isolated from milk. The aim of this study was to evaluate the in vitro antimicrobial activity of Lippia sidoides essential oil (LsEO), popularly known as "rosemary-pepper", and the Stryphnodendron adstringens dry crude extract (SaDCE), or "barbatimao", against bacteria isolated from total milk fl ock, from small farms of northern Minas Gerais state. SaDCE was obtained from the peel of the vegetable through static distillation in ethanol 99.9% during eight days. LsEO was obtained through hydro-distillation of its fresh leaves. The bacteria Escherichia coli and Staphylococcus aureus isolated from milk underwent the test of disk-diffusion and minimum bacterial concentration (MBC), using concentrations of 320, 160, 80, 40, 20 and 0μl/mL of LsEO and 400, 200, 100, 50, 25 and 0mg/mL of SaDCE. All bacteria were sensitive to the vegetable extracts, except the Escherichia coli which was not inhibited by any test when SaDCE was used.