RESUMO
Here, we studied the composition of milk produced by a Holstein herd in the municipality of Nova Boa Vista, Rio Grande do Sul (RS), Brazil. The herd was first managed under a semi-confinement system and subsequently, in a compost bedded dairy barn system to facilitate animal management and, more importantly, family work. We monitored milk production by the herd under a semi-confinement system from January 2013 through September 2015, and then under a compost bedded dairy barn system from October 2015 through December 2017. The seasons of the year were spring (October to December), summer (January to March), autumn (April to June), and winter (July to September). Our results showed an increase in somatic cell count and total bacterial count with the change from semi-confinement to the compost bedded dairy barn system, possibly due to management factors; however, no changes were observed for any other of the variables under study, including lactose, fat, protein, and total solids. In addition, season markedly influenced milk composition and quality; thus, in winter and spring, milk was of a higher quality, whereas in the hotter months of summer and autumn fodder quality and availability, and the incidence of mastitis, as reflected by somatic cell count, affected milk quality negatively.(AU)
Objetivou-se estudar a composição do leite de um rebanho da raça Holandês no município de Nova Boa Vista - RS que era manejado em sistema semiconfinado e posteriormente evoluiu para Compost Bedded Dairy Barn (CBDB) como forma de facilitar o manejo dos animais e principalmente amenizar o trabalho da família. Os dados utilizados são referentes à composição e qualidade do leite entre os meses de janeiro de 2013 a outubro de 2015 em sistema semiconfinado e de novembro de 2015 a dezembro de 2017 em sistema confinado CBDB. As estações do ano foram consideradas da seguinte forma: Primavera (outubro, novembro e dezembro), Verão (janeiro, fevereiro e março), Outono (abril, maio e junho) e Inverno (julho, agosto e setembro). Os resultados mostraram um aumento da contagem de células somáticas (CCS) e da contagem bacteriana (CBT) com a mudança do sistema semiconfinado para o CBDB, ou seja, estes indicadores foram prejudicados quando as vacas estavam em sistema de CBDB, possivelmente em função dos fatores de manejo, porém, não havendo diferenças para as demais variáveis (lactose, gordura, proteína e EST). Além disso, as estações do ano influenciam a qualidade e composição do leite, sendo que no inverno e na primavera o leite apresentava melhor qualidade uma vez que nos meses mais quentes (verão e outono) a qualidade das forragens e a insciência de mastites (refletida na CCS) foram fatores determinantes.(AU)
Assuntos
Animais , Feminino , Estações do Ano , Bovinos , Leite/química , Contagem de Células , Indústria de Laticínios , Carga BacterianaRESUMO
This study was realized to evaluate the monthly production, composition and quality of milk (total and defatted dry extract, lactose, fat and protein) and their relation to somatic cell count (SCC) and total bacterial count (TBC) using multivariate statistical analyses. The data are from a dairy farm for the period of two years (from January 2015 to December 2016). The SCC and TBC variables were transformed to somatic cell score (SCS) and log10 (LogTBC). Factor analysis, discriminant analysis and cluster analysis were used. Through factor analysis, it was found two factors that together explained 69.5% of the total data variation. The first factor represented the inverse relationship between lactose versus fat and protein content, while the second factor represented the inverse relationship among monthly milk yield versus SCS and LogTBC. The discriminant analysis identified that lactose and protein contents and SCS were the variables that had the greatest participation in the separation of the groups formed by the cluster analysis. The groups differed mainly by the monthly production of milk, composition and SCS. Finally, there are important multivariate relations between the variables milk production, composition and quality.
Assuntos
Animais , Bovinos , Bovinos/microbiologia , Carga Bacteriana/veterinária , Leite/microbiologia , Leite/química , Análise FatorialRESUMO
This study was realized to evaluate the monthly production, composition and quality of milk (total and defatted dry extract, lactose, fat and protein) and their relation to somatic cell count (SCC) and total bacterial count (TBC) using multivariate statistical analyses. The data are from a dairy farm for the period of two years (from January 2015 to December 2016). The SCC and TBC variables were transformed to somatic cell score (SCS) and log10 (LogTBC). Factor analysis, discriminant analysis and cluster analysis were used. Through factor analysis, it was found two factors that together explained 69.5% of the total data variation. The first factor represented the inverse relationship between lactose versus fat and protein content, while the second factor represented the inverse relationship among monthly milk yield versus SCS and LogTBC. The discriminant analysis identified that lactose and protein contents and SCS were the variables that had the greatest participation in the separation of the groups formed by the cluster analysis. The groups differed mainly by the monthly production of milk, composition and SCS. Finally, there are important multivariate relations between the variables milk production, composition and quality.(AU)