In situ dry matter and crude protein disappearance dynamics in stockpiled limpograss

Abstract

AbstractStockpiling warm‐season perennial grasses for winter grazing is an important management practice for beef cattle production systems in tropical and subtropical regions. Limpograss [Hemarthria altissima (Poir.) Stapf et C.E. Hubb.] has greater digestibility at late maturity than other commonly used warm‐season perennial grasses; however, decreased crude protein (CP) concentration may limit livestock performance. The objective of this study was to evaluate the in situ dry matter (DM) and CP ruminal disappearance kinetics of stockpiled limpograss herbage. Forage for the in situ study derived from a 2‐yr field experiment in which treatments were the factorial combinations of three cultivars (‘Kenhy’, ‘Gibtuck’, or ‘Floralta’) and three stockpiling periods (8, 12, or 16 wk) distributed in three replicates of a randomized complete block design. Effective degradability of DM was greater for Kenhy and Gibtuck compared with Floralta (614 and 611 vs. 575 g kg−1), and it declined linearly as stockpiling period increased from 8 to 16 wk (623 vs. 586 g kg−1). Herbage CP concentration (48–32 g kg−1 DM) also declined linearly from 8 to 16 wk, but rumen‐unavailable CP increased during stockpiling (257–438 g kg−1 CP), causing effective CP degradability to decrease (637–489 g kg−1 CP). Limpograss is a good option for stockpiled forage, and both new releases outperformed Floralta; however, concentration and availability of CP must be considered when defining a supplementation strategy.