The aim of this work was to evaluate the quality of raw cow's milk during the year depending on the breed. In two agricultural companies, respectively in three farms there were monitored total bacteria count (TBC), somatic cell count (SCC), residues of inhibitory substances (RIS), freezing point, protein content and fat content in 2015. Limits of TBC given by European Union (100,000/ml) were kept in all farms. Limits set for SCC (400,000/ml) were exceeded in 25% samples in breeding I and the average value was significantly increased (p <0.001) in comparison to breeding II and III. These results suggest a possible occurrence of subclinical mastitis. For the company it means a significant economic loss. RIS has not been found in any sample. Average protein content of monitored breeding was not too different (3.69; 3.70; 3.67%). Fat content in breeding I (3.84%) was statistically significantly decreased (p <0.001) in comparison to breeding II and III (4.18 4.12%).

The aim of thesis was to analyze results of raw bulk milk according to these quality indicators: total bacterial count (TBC), somatic cell count (SCC), fat content, protein content, casein content, freezing point, solids-not-fat (SNF) and urea content. Data were evaluated from March 2006 through December 2008 at three farms. All of quality indicators were evaluated in term of farm, year and month. The ANOVA showed a significant effect of farm, year and month on all quality indicators. Limits given by European Union of TBC ({$\leq$}100,000/ml) and SCC ({$\leq$}400,000/ml) were keep in all farms. In first farm were overall means 3.97 % fat, 3.56 % protein, 2.73 % casein percentage, freezing point -0.527 °C, 9.11 % solids-not-fat and 4.8 mmol/l urea. In second farm were overall means 3.89 % fat, 3.47 % protein, 2.68 % casein percentage, freezing point -0.523 °C, 9.01 % solids-not-fat and 3.6 mmol/l urea. In third farm were overall means 3.81 % fat, 3.33 % protein, 2.60 % casein percentage, freezing point -0.522 °C, 8.87 % solids-not-fat and 4.5 mmol/l urea. Results were compared and causes of difference and milk quality variation were explained.

Conselho Nacional de Desenvolvimento Científico e Tecnológico / Neosporosis is an economically important disease caused the protozoan Neospora caninum and is characterized by causing reproductive problems in cattle such as abortion, return to estrus and birth of calves persistently infected. The diagnosis is based mainly on detection of antibodies anti-N.caninum by serological tests, from samples of blood serum and also through milk. The control of this disease is related to the culling of positive animals that showing reproductive disorders, since no commercially available vaccine induces immune response able of preventing transplacental transmission and thus, the parasite remains in the herd. In this study, we performed studies involving the humoral response against the parasite and the detection of antibodies in individual and bulk milk samples for the indirect immunofluorescence assay (IFA). The results are presented in three manuscripts. In chapter one, the aim was to compare serum immunoglobulin G and M, in animals experimentally infected with tachyzoites of NC-1 strain, and animals vaccinated with an inactivated vaccine. The results showed a clear oscillation in antibody titers, revealing that the heifers inoculated immune response was more durable than in those vaccinated. In the second chapter, it was performed a diagnostic test of the anti-N.caninum antibodies from milk samples, using as a test, IFA. When analyzing individual samples of milk, there was a good correlation for samples of blood serum. The higher the serum titer, the greater the probability of detecting antibodies in milk samples, both individual and bulk milk. In chapter three, the aim it was to evaluate the use of bulk milk sample for herd diagnostic or for epidemiological studies, by detecting antibodies. Similar to results obtained in chapter two, the bulk milk sample, when analyzed by IFA demonstrated to be correlated with the number of positive animals in each herd as well as with the titles presented by these animals. Thus, through this study we emphasize that with regard to vaccination, more work needs to be better conducted in order to get an immune response able to protect the fetus longer more time and more importantly, that will prevent or reduce transplacental transmission. Regarding the diagnosis by using the milk samples it was observed that both samples in individual and bulk milk, the IFA can be used safely and is considered an easier way to carry out epidemiological studies in herd cattle. / Neosporose é uma doença economicamente importante causada pelo protozoário Neospora caninum e caracteriza-se por causar problemas reprodutivos em bovinos, como aborto, retorno ao cio e nascimento de bezerros persistentemente infectados. O diagnóstico é baseado, principalmente, na detecção de anticorpos anti-N. caninum através de testes sorológicos, a partir de amostras de soro sanguíneo e também através do leite. O controle dessa enfermidade está relacionado com o descarte dos animais positivos que apresentam desordens reprodutivas, uma vez que a vacina disponível comercialmente não induz resposta imune capaz de prevenir a transmissão transplacentária e assim, o protozoário se mantém no rebanho. Neste estudo, foram realizados trabalhos envolvendo a resposta humoral frente ao protozoário bem como a detecção de anticorpos em amostras individuais e coletivas de leite pela técnica de Imunofluorescência Indireta (RIFI). Os resultados estão apresentados em três artigos. No capítulo um, o objetivo foi comparar a concentração sérica de imunoglobulinas G e M, em animais infectados experimentalmente com taquizoítos da cepa NC-1 e, em animais vacinados com uma vacina inativada. Os resultados obtidos demonstraram uma evidente oscilação no título de anticorpos, sendo possível observar que nas novilhas inoculadas a resposta imune foi mais duradoura que nas vacinadas. No segundo capítulo, buscou-se diagnosticar anticorpos contra o N.caninum a partir de amostras de leite, utilizando como teste, a RIFI. Quando analisadas amostras individuais de leite, observou-se uma boa concordância em relação às amostras de soro sanguíneo. Quanto maior o título sérico, maior é a probabilidade de detectar anticorpos em amostras de leite, tanto individuais, como coletivas. No capítulo três, o objetivo foi avaliar a utilização de amostras coletivas de leite para diagnóstico de rebanho ou para estudos epidemiológicos, através da detecção de anticorpos. Semelhante aos resultados obtidos no capítulo dois, as amostras coletivas de leite, quando analisadas demonstraram estarem correlacionadas com o número de animais positivos de cada rebanho, assim como, com os títulos apresentados por esses animais. Assim, através desse estudo podemos ressaltar que em relação à vacinação, outros trabalhos precisam ser melhor conduzidos, visando buscar uma resposta imune capaz de proteger o feto por mais tempo e o mais importante, que consiga evitar ou reduzir a transmissão transplacentária. Com relação ao diagnóstico através do leite, pode-se determinar que tanto em amostras individuais como coletivas, a RIFI pode ser utilizada com segurança, sendo considerada uma maneira mais fácil de realizar estudos epidemiológicos em nível de rebanho.

The aim of my thesis was to analyze the quality parameters of raw bulk milk with a focus on hygienic and microbiological quality. For this purpose we choose two markers: somatic cell count (SCC) and total bacterial count (TBC). Data were obtained from two dairy farms Dolní Bukovsko and Popovice for the period from June 2008 to February 2011. For statistical evaluation was used MS Excel and Statistics 6.0. SCC and the average TBC values were recorded at higher density in Dolní Bukovsko. However, the averages for these two breeds are consistent with the legislation of the European Union and the Czech Republic (both TBC (?100,000/ml) and SCC (?400,000/ml)). Even though the average TBC value exceeded the limit of the breeding herd health PSB ? 200 thousand / ml, indicating the possible presence of subclinical mastitis and bonded with the considerable economic losses in milk production.