Influence of Maternal Nutrition During Gestation on Feed Efficiency, Productive Performance, and Reproductive Traits of Finishing Beef Bulls

Fetal programming refers to the lasting changes in offspring physiology, productivity, and reproduction that are induced by maternal nutrition during gestation. This study evaluated the effects of maternal nutrition on performance, reproductive traits, and carcass characteristics of Nellore bulls during the finishing phase. Twenty-eight bulls, all sired by the same bull and born to nulliparous dams, were used. During gestation, dams received either mineral supplementation (Non-Programmed group [NP]; 0.3 g/kg of body weight) or protein-energy supplementation (Fetal Programming group [FP]; 5 g/kg of BW). After birth, all calves were managed under similar conditions throughout the cow-calf, growing, and finishing phases. Reproductive traits, including scrotal circumference, sperm motility, vigor, swirling, and defects, were evaluated at 16 and 20 months. Carcass characteristics were assessed by ultrasound every 28 days during a 97-day feedlot period, along with dry matter intake, body weight, and feed efficiency. Maternal nutrition did not affect growth or carcass traits (P ≥ 0.18). However, FP bulls showed reduced minor and total sperm defects (P ≤ 0.04) and a trend toward lower motility (P = 0.06). Protein-energy supplementation during gestation did not affect productive performance but did influence sperm quality, suggesting specific effects of fetal programming on male reproductive development.