N-3 Polyunsaturated Fatty Acids as a Nutritional Support of the Reproductive and Immune System of Cattle—A Review

SIMPLE SUMMARY: This review focuses on two crucial aspects of cattle breeding: the reproduction of dairy cows and the health status and body condition of cows during the periparturient period, as well as the immunity of newborn calves. The energetic importance of fat in ruminant nutrition and lipids metabolism in the rumen, the regulatory role of n-3 fatty acids in the reproduction of ruminants, their importance in fetus developmental programming and embryo development, as well as the role of n-3 fatty acids a key component in the building of the immunity of newborn calves, are discussed. ABSTRACT: This paper focuses on the role of n-3 fatty acids as a nutrient crucial to the proper functioning of reproductive and immune systems in cattle. Emphasis was placed on the connection between maternal and offspring immunity. The summarized results confirm the importance and beneficial effect of n-3 family fatty acids on ruminant organisms. Meanwhile, dietary n-3 fatty acids supplementation, especially during the critical first week for dairy cows experiencing their peripartum period, in general, is expected to enhance reproductive performance, and the impact of its supplementation appears to be dependent on body condition scores of cows during the drying period, the severity of the negative energy balance, and the amount of fat in the basic feed ration. An unbalanced, insufficient, or excessive fatty acid supplementation of cows’ diets in the early stages of pregnancy (during fetus development) may affect both the metabolic and nutritional programming of the offspring. The presence of the polyunsaturated fatty acids of the n-3 family in the calves’ ration affects not only the performance of calves but also the immune response, antioxidant status, and overall metabolism of the future adult cow.