The objective of this study was to analyze colostrum and milk compositions of ewes kept in pasture receiving different types/levels of supplementation and to analyze milk composition variation throughout the initial third lactation period. After confirmation of pregnancy, 54 ewes were kept in pasture and supplemented from the final third of gestation until weaning with multiple mixture or concentrate (0.4% or 0.8% of body weight). Milk collections were carried out in the postpartum period to collect colostrum (day 0), and on the seventh, 14th, 21st and 28th milking days. Samples were obtained by manual milking and analyzed for protein, fat, casein, lactose, total solids and defatted dry extract. No effects from the different types of supplementation were observed on the colostrum composition or in relation to milk composition. An effect of supplementation was only found for lactose contents, which were higher for animals that consumed a higher level of supplementation. In relation to the milking days, a linear decrease in protein, casein, total solids and defatted dry extract contents was observed between the seventh and the 28th day of lactation. No interaction between type of supplementation and the milking days was observed. The different types of supplementation did not alter the colostrum composition of Santa Inês crossbred ewes, however they had an influence on milk composition. Protein, casein, total solids and defatted dry extract decrease linearly between the seventh and the 28th day of lactation.