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

Abstract

Stockpiling 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.

Herbage accumulation and nutritive value of stockpiled limpograss and ‘Tifton 85' bermudagrass

“…In accordance with our study, Wallau et al. (2020) indicated that limpograss CP decreased linearly from 8 to 16 wk of stockpiling period.…”

“…This was probably because the average temperature in January 2017 was greater than in January 2016 (Table 1), resulting in the growth of new plant material with greater nutritive value. In accordance with our study, Wallau et al (2020) indicated that limpograss CP decreased linearly from 8 to 16 wk of stockpiling period.…”

Canopy characterization and nutritive value of stockpiled ‘Floralta’ limpograss

“…Studies report limpograss as a successful alternative to stockpiling pastures during the cold season or mild winters in subtropical regions (Quesenberry & Ocumpaugh, 1980). The use of stockpiled pasture in beef cattle production systems is a management practice that aims to extend the grazing season and reduce the need for costly supplements (Wallau et al., 2020). Limpograss has been widely planted in beef cattle operations in the southeastern United States due not only to cold tolerance, but also due to a slower decrease in digestibility with increasing plant maturity (Quesenberry et al., 2004; Vendramini et al., 2008; Wallau et al., 2015).…”

“…Wallau et al. (2020) evaluated the in‐situ kinetics of dry matter (DM) and the disappearance of crude protein (CP) from a stockpiled pasture of limpograss for 2 yr, and obtained an average forage accumulation variation of 5,300 and 7,700 kg ha −1 , between the start and end date of evaluation, respectively. In addition to a faster growth rate than bahiagrass ( Paspalum notatum Fluggé), a grass widely used in Florida, limpograss has similar leaf and stem digestibility (Pitman et al., 1994).…”

“…Limpograss has been widely planted in beef cattle operations in the southeastern United States due not only to cold tolerance, but also due to a slower decrease in digestibility with increasing plant maturity (Quesenberry et al, 2004;Vendramini et al, 2008;Wallau et al, 2015). Wallau et al (2020) evaluated the in-situ kinetics of dry matter (DM) and the disappearance of crude protein (CP) from a stockpiled pasture of limpograss for 2 yr, and obtained an average forage accumulation variation of 5,300 and 7,700 kg ha −1 , between the start and end date of evaluation, respectively. In addition to a faster growth rate than bahiagrass (Paspalum notatum Fluggé), a grass widely used in Florida, limpograss has similar leaf and stem digestibility (Pitman et al, 1994).…”