Desempenho da recria sob o efeito do histórico alimentar com silagens de ração total na gestação.

Abstract

This study aimed to assess the performance of offspring during the rearing phase, taking into account the supplementation of their dams with two distinct SRTs in the second third of gestation and possible interaction of maternal nutrition (MN) with offspring sex (OS). The study involved 33 Tabapuã beef cows initially managed on aUrochloabrizantha cv Marandu pasture. At the beginning of the second third of pregnancy, these cows were transitioned from the pasture to confinement with individual pens. The cows were divided into two groups, each receiving different SRTs. One group was fed Marandu grass and DDG (DDG, n = 17), while the other received Marandu grass, soybean hulls, and urea (SH, n = 16). Both diets were isoproteic. At the end of the second third of gestation, the cows returned to the pasture area and received only a mineral mixture. Subsequently, the offspring were evaluated throughout the rearing period, lasting 94 days. Males demonstrated significantly higher (P < 0.05) intake of dry matter (DM), crude protein (CP), neutral detergent fiber (NDF), ether extract (EE), and organic matter (OM) compared to females. An MN × OS interaction was verified for the weaning weight (P = 0.04), with males in the CS treatment exhibiting greater weight than those in the other treatments. During the 35 and 64 days of the rearing phase, CS-males maintained higher weights (P = 0.05). A trend towards a MN × OS interaction was verified for the final weight (P = 0.07), in which CS-males were heavier. The average daily gain (ADG) at 35 days of rearing was higher for DDG-males (P = 0.04). In the same period, females had a smaller gain compared to males (P < 0.01). There was a difference in the sex of the progeny to total ADG (P < 0.01), where males had a greater ADG compared to females. Maternal nutrition had an impact on CA (P = 0.01), with better CA in DDG-treated animals compared to the CS treatment. Maternal nutrition did not exert a significant influence on the other carcass measurements (P > 0.05). Females had a lower initial P8 area than males (P < 0.01). There was an MN × OS interaction for the final P8 area, where CS-treated males had a greater area compared to the other treatments. The different levels of undegraded protein in the rumen (RUP), during the middle third of gestation can affect the performance and carcass characteristics of the progenies throughout their postnatal life.