Performance and feed intake of Nellore steers in extensive, intensive, and integrated pasture-based beef cattle production systems

Abstract

This study evaluated the effects of five pasture-based production systems on the backgrounding-finishing phase performance and feed intake traits of Nellore steers. Over two years (2019–2021), steers (three/year/experimental unit) were randomly assigned to five treatments (with two replicates): 1) degraded pasture without nitrogen (N) fertilization (DP0); 2) silvopastoral with 200 kg N ha⁻¹ (SP200); 3) rainfed pasture with 200 kg N ha⁻¹ (RP200); 4) rainfed pasture with 400 kg N ha⁻¹ (RP400); and 5) irrigated pasture with 600 kg N ha⁻¹ (IP600). Animals grazed exclusively, receiving water and mineral-protein supplement ad libitum. IP600, RP400, and RP200 resulted in the highest Forage and Total Dry Matter Intake (DMI), correlating to superior performance. Supplement DMI was highest in DP0 and lowest in IP600. Considering the seasons, higher stocking rates [expressed in Animal Units (AU) and Equivalents (AE)] were observed in IP600 compared with SP200 (spring and winter), and with RP200, DP0 and SP200 (summer and autumn). Forage allowance and feed efficiency varied seasonally across treatments, influenced by defoliation frequency, intake patterns, and leaf preference during grazing intensity adjustments. During the dry period, performance declined across most treatments due to reduced pasture production, except for IP600, RP400, and RP200, which demonstrated resilience to drought and seasonal variability. Intensified and well-managed systems (IP600, RP400, and RP200) enhanced animal performance and feed intake, suggesting their potential as sustainable pasture management strategies. SP200 and DP0, however, may require tailored management strategies to optimize their benefits.