ABSTRACT
BACKGROUND: Gyr cows are well adapted to tropical conditions, resistant to some tropical diseases and have satisfactory milk production. However, Gyr dairy herds have a high prevalence of subclinical mastitis, which negatively affects their milk yield and composition. The objectives of this study were (i) to evaluate the effects of seasonality, mammary quarter location (rear x front), mastitis-causing pathogen species, and somatic cell count (SCC) on milk composition in Gyr cows with mammary quarters as the experimental units and (ii) to evaluate the effects of seasonality and somatic cell count (SCC) on milk composition in Gyr cows with cows as the experimental units. A total of 221 lactating Gyr cows from three commercial dairy farms were selected for this study. Individual foremilk quarter samples and composite milk samples were collected once a month over one year from all lactating cows for analysis of SCC, milk composition, and bacteriological culture. RESULTS: Subclinical mastitis reduced lactose, nonfat solids and total solids content, but no difference was found in the protein and fat content between infected and uninfected quarters. Seasonality influenced milk composition both in mammary quarters and composite milk samples. Nevertheless, there was no effect of mammary quarter position on milk composition. Mastitis-causing pathogens affected protein, lactose, nonfat solids, and total solids content, but not milk fat content. Somatic cell count levels affected milk composition in both mammary quarters and composite samples of milk. CONCLUSIONS: Intramammary infections in Gyr cows alter milk composition; however, the degree of change depends on the mastitis-causing pathogen. Somatic cell count is negatively associated with reduced lactose and nonfat solids content in milk. Seasonality significantly affects milk composition, in which the concentration of lactose, fat, protein, nonfat solids and total solids differs between dry and wet seasons in Gyr cows.
Subject(s)
Mastitis, Bovine/microbiology , Milk/cytology , Animals , Asymptomatic Infections , Brazil , Cattle , Cell Count/veterinary , Corynebacterium , Corynebacterium Infections/veterinary , Fats/analysis , Female , Lactation/metabolism , Lactose/analysis , Mammary Glands, Animal/metabolism , Mammary Glands, Animal/microbiology , Mastitis, Bovine/metabolism , Milk/chemistry , Milk Proteins/analysis , Seasons , Staphylococcal Infections/veterinary , Streptococcal Infections/veterinaryABSTRACT
A brucelose canina é uma importante zoonose que tem sido investigada freqüentemente em cães como medida sanitária de controle da saúde pública. Foi conduzido um estudo sorológico para investigar a freqüência da brucelose canina por Brucella canis e por Brucella abortus, em 500 cães errantes na cidade de São João da Boa Vista/SP - Brasil, utilizando as técnicas de imunodifusão em gel de ágar (antígeno de parede celular de B. ovis) e imunoaglutinação em placa com antígeno acidificado tamponado. Este estudo mostrou baixa frequência de cães infectados por B. canis 4/500 (0,8%) e ausência de soros positivos para B. abortus
Dogs brucellosis may cause reprodutive problems and there are a risk factors for human health. The prevalence of brucellosis due to Brucella canis and Brucella abortus was investigated in dogs living in urban areas of São João da Boa Vista/SP - Brasil. For this purpose, 500 blood sample were collected and serum analysed by agar gel immuno diffusion test and Rose-Bengal test. The frequency of brucellosis due to B. canis was 4/500 (0,8%) and negative for B. abortus.
