beef cattle production, farm feed profile, feed conversion efficiency (FCE), metabolic energy budgeting (MEB), Oil Palm Silvopastoral Systems (OPS), Agriculture (General), S1-972, Plant culture, SB1-1110

Abstract Background Oil palm is a tropical crop with worldwide plantings approaching 20 million ha and large areas in Indonesia, Malaysia and Thailand. The plantations are readily managed as silvopastoral systems incorporating cattle grazing (Oil Palm Silvopastoral System for Cattle, OPSC) but there is a need for analytical tools and data to understand system herbage supply and feed conversion efficiency (FCE). Methods Metabolic energy budgeting was used to estimate herbage harvested by cattle in three OPSC subsystems, 9 and 12 years after oil palm establishment, and FCE of the subsystems was determined. Understorey herbage was also analysed for nutritive value, botanical composition and herbage accumulation within one grazing‐regrowth cycle. Results The herbage‐harvested estimate was 2.0−2.4 t dry matter (DM) ha−1 year−1 for 9 year old subsystems and 1.4−1.7 t DM ha−1 year−1 for a 12 year old subsystem. Herbage metabolisable energy (ME) was 8.3−8.5 MJ kg−1 DM and crude protein (CP) was 15%−16% DM. FCE values for subsystems ranged from 32 to 94 kg DM kg−1 liveweight‐gain. Conclusions Herbage DM yield is declining, while herbage ME is marginal but CP is adequate. FCE is suboptimal but can be optimised by defining the trajectory of declining herbage production with canopy closure as plantations age and matching stocking rate to herbage supply using a comparative‐stocking‐rate‐type statistic.