The knowledge ofthe importance of nutrition on animal reproduction is well known for producersand researchers for a long time. However, contemporary studies have broughtnew perspectives and further details of this relationship, allowing fine-tuningof diets handling in order to increase production and reproduction in ruminants.Nevertheless, especially in high-producing dairy cows, there are still seriousmultifactorial fertility problems, with a heavy nutritional involvement. Incontrast, addition of certain ingredients to the diet, such as fat rich in polyunsaturatedfatty acids and reducing the supply of rumen degradable protein have on severaloccasions, resulted in an increased reproductive performance in dairy and beefcattle. Thus, this article presents and discusses results of some relevant paperson this subject, especially those related to the influence of energy or proteinon reproduction.
