Optimising Sheep Diets for Sustainability: Corn or Barley with Alfalfa?

Forages like alfalfa haylage (AH), which are high in crude protein (CP), require energy-rich supplements to optimise nutrient intake, improve digestibility, and enhance nitrogen use efficiency thereby promoting sustainability in livestock production. The objective of the study was to determine whether corn or barley serves as better supplement to AH for achieving these goals. A feeding trial was conducted as an incomplete change-over design with four treatments, four periods, and four animals per period. The concentrate was fed at a rate of 30 g kg−1 M0.75 wether sheep d−1 and consisted of: (i) 100% corn (CG), (ii) 67% corn and 33% barley (CG67), (iii) 33% corn and 67% barley (BG67), and (iv) 100% barley (BG). CG67 showed lower dry matter intake (DMI) (p < 0.001) but higher dry matter (DM) digestibility (p < 0.01). BG had the highest intake of neutral detergent fibre (NDF) (p < 0.01), CP (p < 0.001), and CP digestibility (p < 0.001). Both BG and BG67 exhibited higher N balance than CG and CG67 (p < 0.001). The results suggest that, given the quality of AH and the concentrate level of 30 g kg−1 M0.75 used in this study, supplementing barley to an AH-based diet is more beneficial for enhancing sustainability in sheep nutrition than supplementing corn.