In the present review, the authors summarize the potential effects of energy, carbohydrate, protein, and amino acid supplementation on the reproductive performance of dairy and beef cattle, focusing on the development and quality of the ovum and the preimplantation embryo. Excess dry matter and energy intake can have a positive or negative effect on the development of the preovulatory follicle and embryo, depending on the body condition, the physiological status and the actual milk production of the cows. In this review, the importance of hormones (e.g. insulin, insulin-like growth factor and leptin) were taken into consideration regarding their role in the reproductive performance of the dairy and beef cattle. Feeding high levels of non-fibre car-bohydrates (NFC) can lead to hyperinsulinaemia and deteriorating results in embryo production. It is well-known that the type and composition of carbohydrates in the diet alter several physiological processes, but there is no exact information about the effects of carbohydrate-composition on the follicular development and embryo quality. High protein intake, particularly the rumen degradable protein (RDP), increases plasma urea concentration. High urea levels can lead to poor reproductive performance in cattle. Urea has a direct negative effect on the final stages of follicular development and indirectly alters embryonic development by decreasing pH in the uterine fluid. The levels of certain amino acids in the lumen of the pregnant uterus are significantly higher than before pregnancy. Methionine, lysine and histidine have the greatest rise at the presence of the preimplantation embryo. Feeding rumen-protected forms of these amino acids can positively alter embryo production, but further investigation is needed in this field. The authors deem that more research is needed to lay effective feeding strategies for the success of embryo production.