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Gamba grass (Andropogon gayanus Kunth) is a tussock-forming forage species adapted to acid soils of Brazilian savannas and cultivated for grazing pastures. Four decades since its release, Planaltina prevails as the most commercialized cultivar of the species, even though the new cultivar BRS Sarandi could be a better alternative for Gamba-grass-based farms by presenting a greater leaf:stem ratio. The objective of this study was to evaluate the average daily live weight gain (ADG) of Nellore bulls (Bos indicus) for two Gamba grass cultivars—Planaltina and Sarandi. The experiment was conducted in Planaltina, Federal District, Brazil, for 3 years, namely 2018, 2018–2019, and 2020. The experimental design was a completely randomized block design with two treatments and three replicates, each one continuously stocked at three stocking rates (SR)—1.3, 2.6, and 4 young bulls/ha. Canopy height (CH), forage mass (FM), plant-part proportion (green leaf, stem, and dead material), and nutritive value were evaluated. In 2018, mean ADG for Sarandi pastures was greater (0.690 kg/bull/d) than that of Planaltina (0.490 kg/bull/d) (p < 0.10). In the subsequent year (2018–2019), there was no effect of cultivar (p > 0.10), while in 2020 the ADG was again affected by cultivar (p < 0.10), confirming the advantage of Sarandi (0.790 kg/bull/d) over Planaltina (0.650 kg/bull/d). In 2018 and 2020, the percentage of stems for Sarandi was about 3–6 pp less than for Planaltina (p < 0.10). As well as for stems, Sarandi pastures presented a shorter CH in 2028 and 2020 (6–7%) (p < 0.10). The positive high correlation of leaf:stem ratio with ADG (r = 0.70) probably predisposed the superiority of Sarandi over Planaltina. The distinguishing plant-part composition of Sarandi canopy promotes increasing weight gain of beef cattle when compared to cv. Planaltina. [ABSTRACT FROM AUTHOR]

This study estimated genetic and phenotypic parameters, heritabilities, correlations, selection accuracy, and expected gain from selection for dry matter yield and nutritional traits in 178 half-sib ruzigrass families. Eight traits were evaluated, with nutritional quality measured via NIRS. Data analysis using mixed models and clustering revealed significant differences between progenies. Narrow-sense heritability ranged from 0.26 to 0.42, and selection accuracy ranged from 0.51 to 0.65. Genetic variation was lower for nutritional quality traits compared to dry matter yield. Dry matter yield had positive genetic correlations with neutral and acid detergent fiber and cellulose, but negative correlations with crude protein and hemicellulose. Clustering identified two groups of families: one correlated with in vitro dry matter digestibility and crude protein, and the other with remaining traits. Selecting for dry matter yield may reduce crude protein content but not affect digestibility; selecting for low fiber or high crude protein may improve forage quality. [ABSTRACT FROM AUTHOR]