Temperate pasture- or concentrate-beef production systems: steer performance, meat nutritional value, land-use, food–feed competition, economic and environmental sustainability

Abstract

The objective was to evaluate steer performance, meat nutritional value, land-use, food–feed competition and both economic and environmental sustainability within temperate pasture-based suckler weanling-to-beef systems with or without (forage-only) concentrates. Post-weaning, 8-month-old, late-maturing breed steers (333 kg) were assigned to one of three systems: (1) grass silage + 1.2 kg concentrate DM (148 days), followed by pasture (123 days) and finished on ad libitum concentrates (120 days) – slaughter age, 21 months (GRAIN); (2) as per (1) but pasture (196 days) and finished on grass silage ad libitum + 3.5 kg concentrate DM (124 days) – slaughter age, 24 months (SIL + GRAIN); and (3) grass silage-only (148 days), pasture (196 days), silage-only (140 days) and finished on pasture (97 days) – slaughter age, 28 months (FORAGE). The mean target carcass weight was 390 kg for each system. Data generated were used to parameterize a farm-level beef systems model. Concentrate DM intake was 1187, 606 and 0 kg/head for GRAIN, SIL + GRAIN and FORAGE, respectively. The forage-only (FORAGE) system offers several advantages, including improved farm profitability, enhanced meat fatty acid profile and only utilized inedible human feed. Consequently, associated greenhouse gas (GHG) emissions per net human edible food produced were more favourable for FORAGE. However, compared to GRAIN, the FORAGE system had an older age at slaughter and associated increased pasture land-use and GHG emissions per animal, meat weight gain and essential amino acids gain. There are therefore inevitable trade-offs, as one beef system does not improve all sustainability and GHG emission metrics.