This Study was carried out to evaluate the changes in composition, heat stability and quality characteristics of Egyptian buffaloes' and cows' colostrum collected at calving, 4, 12, 24, 48, 72h and after 336h (14 days) of parturition. Total solids, total protein, whey proteins, fat, lactose and ash contents, some elements, vitamins (A and E) were determined. Heat stability, titrable acidity, pH value, specific gravity and viscosity were also estimated.
Total protein and whey proteins concentration were higher in cow than in buffalo colostrum, while total solids, fat, lactose and ash concentrations were higher in buffalo than in cow colostrum. All components decreased gradually as the transition period advanced except lactose which conversely increased. After 72h post-partum, concentration of total protein, whey proteins, fat, ash and total solids decreased by 47.2,72.2, 29.9, 30.0 and 28.9% for buffalo and by 45.1, 73.2, 31.5, 16.4 and 33.0% for cow colostrum. However, lactose concentration increased by 60.0% for buffalo and 68.4% for cow colostrum. The elements concentration of both colostrums tended to decline slightly toward normality on the 14^th day of parturition. Buffalo colostrum had a higher concentration of vitamin E than cow colostrum while, cow colostrum had a higher concentration of vitamin A in buffalo colostrum after 4h of partupition. The heat stability of  buffalo and cow colostrums after 4h postpartum milk was 5.5 and 7.0 min respectively, and gradually increased in consequent milking i.e. 12h ( 8.7and 12.0 min), 24h (15 and 20 min), 48h. (24 and 29), and 72h. (30 and 41min), respectively. No coagulation/precipitation was occurred in 14^th days postpartum milk. Average acidity, pH, specific gravity and viscosity of buffalo and cow colostrum after 4h.  postpartum milk was (0.39 and 0.33%), (6.3 and 6.35), (1.06 and 1.05), (5.8 and 5.05 cP) respectively, and significantly declined to (0.17 and 0.16%), (6.6 and 6.7), (1.o34 and 1.032) and (1.10 and 1.02cP), respectively in 14^th day  postpartum milk.
Therefore, the study recommends the need to address both bovine or buffalo colostrum during the first 72hours of birth and that of high nutritional value.