Colostrum is the first secretion of the mammary gland and is used as an essential food for newborns in the first hours of life. The objective of this work is to evaluate the nutritional quality of colostrum in the postpartum period, its variation over 72 hours and its influence on lamb weight gain. The experiment was carried out using 38 crossbred ewes from Texel and Suffolk and their respective lambs, evaluating values of protein, fat, lactose, total solids, salts, density and freezing point. On the first day, mean values of 8.59%, 10.53%, 12.93%, 23.13%, 1.90%, 1071.72 g/dL and -2.28ºC were found, respectively. On the second day it showed 6.08%, 9.39%, 9.64%, 16.13%, 1.32%, 1050.58g/dL and -1.29ºC and on the third it showed 4.92%, 8.37%, 7.69%, 13.08%, 1.06%, 1043.22 g/dL and -0.93ºC. The lambs had an average weight gain of 0.33 kg in the first 24 hours of life and 0.32 kg in the following 48 hours. It is concluded that it proved to be efficient to verify the quality of the colostrum of the ewes and in the way in which the neonates respond physiologically