Supplementation of bovine females in grazing: Nutritional and reproductive aspects

Abstract

Brazil has a cattle production chain based on grazing production, which makes it inexpensive, but with a low profit margin. For that reason, it has gone through a series of changes due to competition with other animal protein production chains, such as pigs and poultry and also with the agriculture, which rapidly moves into areas that were previously occupied for the livestock farming. Thus, with a scenario of low profitability and high competition, it is necessary to find alternatives that allow its survival and profitability. Even with the largest commercial herd in the world, Brazilian livestock presents levels below its true potential, especially due to the low reproductive efficiency of the females of the herd. So that the activity becomes sustainable, it is important the inclusion of technologies to make use of the maximum productive capacity of these animals. Recently, many studies have been done regarding the supplementation of grazing females, and it presents itself as an essential alternative in both the birth or rearing processes, in view of the fact that the adequate intake of nutrients is essential for reproductive development in cattle. The Zebu extensive management system, which is used in most of the cattle farms in Brazil, is the main cause of the delayed puberty of these animals, which will interfere in the age they went into the breeding season and the age of the first calving.  Also during pregnancy the proper nutritional support is extremely important, evidence shows that the development of the skeletal muscle and deposition of adipose tissue of the fetus may be altered in cases of malnutrition, with long-term effects on their performance in adulthood. This study aimed at pointing out some aspects that confirm the influence of nutrition on reproductive physiology of grazing females receiving supplementation.