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The purpose of the present trial was to investigate the influence of lactation stage on milk cellularity and physicochemical characteristics. Thus, 143 milk samples from 33 Santa Ines ewes negative in the bacteriological examination and without any alteration in the strip cup test were used to determine the automatic and microscopic somatic cell count (SCC), and the fat, lactose, protein and total solids content. The results of the present study showed an augment in the SCC and in the fat and protein content, besides a reduction in lactose content at the last lactation stage. Otherwise, no alteration was observed in the total solids content during the lactation period. This study pointed out to a significant correlation between the automatic SCC and the microscopic SCC (r = 0.80), percentage of polymorphonuclear leukocytes (r = 0.45), percentage of mononuclear leukocytes (r = -0.45), lactose (r = - 0.44), protein (r = 0.37) and fat (r = 0.30) content. Nevertheless, significant correlation between the automatic SCC and the total solids content was not observed.

The measurement of pH in milk is one of the most important and frequent procedures performed in biochemistry practices. This variable is applied to the diagnosis of mammary gland disease, assessment of industrial yields, and identification of metabolic diseases. The objective of this study was to evaluate de effect of freezing the milk from healthy and infected mammary glands of Santa Ines ewes on the pH. The bacteriological culture of 183 milk samples was analyzed resulting in 146 negative and 37 positive samples. From these, the hydrogen ion concentration was determined on sampling day and after freezing at -20°C for 30 months. A reduction on pH was observed after freezing, and the bacteriological positive samples showed the highest pH values. A higher decrease of the pH after freezing was seen in positive samples. Thus, the kind of conservation of milk samples should be considered, as well as the results of parameters that could be influenced by such variation.

The objectives of the present study were the analysis of cell counts, the comparison between different methods for counting cells and the quantification of different types of cells observed in the milk of Lacaune sheep, using automatic somatic cell counts (SCC) and direct microscopic SCC. Milk smears were stained with methyl green-pyronin-Y and Rosenfeld stain. Mean of automatic cell counts was 0.145 x106 cells/mL of milk, and mean of direct microscopic counts using methyl green-pyronin-Y and Rosenfeld were respectively 0.157 and 0.193 x106 cells /mL of milk. Samples used in direct microscopic counts were evaluated according to the different types of cells and the following results were recorded: 0.094 and 0.14 x106 mononuclear cells /mL, 0.063 and 0.051 x106 polymorphonuclear cells /mL of milk using methyl green-pyronin-Y and Rosenfeld stain, respectively. It may be concluded that there were differences in the methods used for counting cells. The number of cells recorded was lower when methyl green-pyronin-Y and automatic counts were used, compared with direct microscopy using Rosenfeld stain.KEY WORDS: somatic cells and cytology, lacaune, milk, sheep. O presente estudo teve como objetivo a análise da celularidade, a comparação dos diferentes métodos de contagem celular e a quantificação dos diferentes tipos celulares presentes no leite de ovelha da raça Lacaune através da contagem de células somáticas (CCS) automática e da CCS microscópica. Coraram-se os esfregaços lácteos com os corantes verde de metil e pironina-Y e Rosenfeld. O valor mediano da contagem celular automática foi de 0,145 x106 células/mL de leite, e os valores das contagens microscópicas diretas utilizando verde de metil e pironina-Y e Rosenfeld foram respectivamente de 0,157 e 0,193 x106 células/mL de leite. Avaliaram-se as amostras destinadas às contagens microscópicas diretas de acordo com os diferentes tipos celulares, encontrando-se os valores de 0,094 e 0,14 x106 células mononucleares/mL, 0,063 e 0,051 x106 células polimorfonuclares/mL de leite na coloração de verde de metil e pironina-Y e Rosenfeld, respectivamente. Portanto, pode-se concluir que houve diferenças entre os métodos de contagem celular. Com o corante verde de metil e pironina-Y e a contagem automática, o número de células encontrado foi inferior, quando comparados com a microscopia direta utilizando o corante de Rosenfeld.PALAVRAS-CHAVES: Células somáticas e citologia, Lacaune, leite, ovelha.

O presente estudo teve como objetivo a análise da celularidade, a comparação dos diferentes métodos de contagem celular e a quantificação dos diferentes tipos celulares presentes no leite de ovelha da raça Lacaune através da contagem de células somáticas (CCS) automática e da CCS microscópica. Coraram-se os esfregaços lácteos com os corantes verde de metil e pironina-Y e Rosenfeld. O valor mediano da contagem celular automática foi de 0,145 x106 células/mL de leite, e os valores das contagens microscópicas diretas utilizando verde de metil e pironina-Y e Rosenfeld foram respectivamente de 0,157 e 0,193 x106 células/mL de leite. Avaliaram-se as amostras destinadas às contagens microscópicas diretas de acordo com os diferentes tipos celulares, encontrando-se os valores de 0,094 e 0,14 x106 células mononucleares/mL, 0,063 e 0,051 x106 células polimorfonuclares/mL de leite na coloração de verde de metil e pironina-Y e Rosenfeld, respectivamente. Portanto, pode-se concluir que houve diferenças entre os métodos de contagem celular. Com o corante verde de metil e pironina-Y e a contagem automática, o número de células encontrado foi inferior, quando comparados com a microscopia direta utilizando o corante de Rosenfeld. PALAVRAS-CHAVES: Células somáticas e citologia, Lacaune, leite, ovelha.