Pseudomonas spp. and P. fluorescens: population in refrigerated raw milk.Ciência Rural, v.47, n.1, 2017. IntRoDuCtIonGuidelines for cooling milk in dairy farms and its transportation were established in Brazil in 2002 (BRaSIl, 2002 as a response to international regulations and market demands. Since then, changes in milk chain production profile and qualitative advances in the regulation of total bacterial (TBC) and somatic cell (SCC) counts in raw milk have occurred (BRaSIl, 2002), and the guidelines were updated in 2011 (BRaSIl, 2011

<p class="Pa7">The aims of present study were to evaluate the effects of milk somatic cell count (SCC) and heat stress on yield and milk composition of cows in a herd for commercial production in a temperate region during the period 2008-2012. Data from the monthly milk test-day records of 161±9 Holstein, totaling 9,650 milkings, were provided by the Association of Holstein Cattle Breeders of Parana State, and analyzed by descriptive analysis, correlation, analysis of variance, and regression analysis. The average daily milk yield was 31.78 kg/cow, which decreased to 29.31% when the somatic cell score (SCS) was 9, and to 11% when the Equivalent Temperature Index (ETI) was 32 or above. Lactose content decreased from SCS 0 until 9 and fat content decreased from SCS 1 until 9, totaling decrease 7.88 and 9.23%, respectively, when the SCS was 9. An opposite effect was observed for the protein content, which increased by 3.6% at SCS 8, when compared to SCS 0. Losses were observed in the daily total solids production from the SCS 0, totaling 30.64% at SCS 9.The increase in ETI to 32 or above reduced all milk constituents as much as 3.42%, except protein. These results, combined with the losses in milk yield at that ETI level, led to a decrease of up to 12.74% of milk solids. It is concluded that since losses in milk quality and yield resulting from SCC and ETI are significant, actions to prevent infection in the mammary gland and to provide a comfortable environment for dairy cattle are needed even in temperate regions.</p>

The aims of present study were to evaluate the effects of milk somatic cell count (SCC) and heat stress on yield and milk composition of cows in a herd for commercial production in a temperate region during the period [2008][2009][2010][2011][2012]. Data from the monthly milk test-day records of 161±9 Holstein, totaling 9,650 milkings, were provided by the Association of Holstein Cattle Breeders of Parana State, and analyzed by descriptive analysis, correlation, analysis of variance, and regression analysis. The average daily milk yield was 31.78 kg/cow, which decreased to 29.31% when the somatic cell score (SCS) was 9, and to 11% when the Equivalent Temperature Index (ETI) was 32 or above. Lactose content decreased from SCS 0 until 9 and fat content decreased from SCS 1 until 9, totaling decrease 7.88 and 9.23%, respectively, when the SCS was 9. An opposite effect was observed for the protein content, which increased by 3.6% at SCS 8, when compared to SCS 0. Losses were observed in the daily total solids production from the SCS 0, totaling 30.64% at SCS 9.The increase in ETI to 32 or above reduced all milk constituents as much as 3.42%, except protein. These results, combined with the losses in milk yield at that ETI level, led to a decrease of up to 12.74% of milk solids. It is concluded that since losses in milk quality and yield resulting from SCC and ETI are significant, actions to prevent infection in the mammary gland and to provide a comfortable environment for dairy cattle are needed even in temperate regions. ResumoO objetivo deste estudo foi avaliar a influencia da contagem de células somáticas (CCS) no leite e o estresse térmico sobre a produção e composição do leite de vacas de um rebanho de produção comercial em região de clima temperado, durante o período de 2008 a 2012. Os dados do dia de controle leiteiro de 161±9 vacas Holandesas, totalizando 9650 ordenhas, foram fornecidos pela Associação Paranaense de Criadores de Bovinos da Raça Holandesa e analisados através de estatística descritiva, correlação, análise de variância e regressão. A produção média diária de leite foi de 31,78 kg/vaca, com diminuição de 29,31% quando o escore de contagem de células somáticas (ECS) foi 9 e até 11% quando o Índice de Temperatura Equivalente (ITE) foi 32 ou maior. Os teores de lactose decresceram a partir do ECS 0 até 9 e de gordura a partir de ECS 1 até 9, totalizando diminuição de 7,88 e 9,23%, respectivamente, quando o ECCS foi 9. Um efeito inverso foi observado em relação ao teor de proteína, o qual aumentou 3,6% com ECS 8, comparado com o ECS 0. A produção diária de sólidos totais iniciou perdas a partir do ECS 0 e totalizou perdas de 30,64% quando este foi 9. O aumento do ITE até 32 ou mais diminuiu a concentração de todos os componentes do leite, exceto de proteína, em valores de até 3,42% da concentração. Estes efeitos, somados a diminuição na produção diária de leite com este nível de ITE, totalizaram perdas de até 12,74% na produção de sólidos totais. Conclui-se que as perdas de produção e qua...

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