Multi-omics insights into triticale silage as a sustainable alternative to corn silage in heifer diets

Intensive ruminant production systems rely heavily on corn silage (CS) as a primary forage source; however, its resource-intensive cultivation and environmental constraints necessitate the development of sustainable alternatives.

In a 90-day feeding trial, 24 growing heifers were assigned to diets in which CS was replaced by triticale silage (TS) at 0, 25, 50%, or 100% (DM basis). Growth performance, rumen fermentation, ruminal fatty acid (FA) profiles, and integrated rumen microbiome-metabolome interactions were evaluated.

A 25% substitution (TS25) as the optimal level, maintaining growth performance comparable to the control while achieving the lowest feed cost of gain. TS25 improved rumen fermentation (lower A: P and high total VFA), promoted more efficient nitrogen utilization (higher MCP with lower ammonia N), and enriched functionally relevant bacteria associated with fiber degradation and fermentation (e.g., Ruminococcus, Prevotella, and Rikenellaceae_RC9_gut_group). Consistently, TS inclusion shifted ruminal lipid metabolism, increasing UFA proportions and elevating PUFA (TS25 and TS50 increased PUFA by 15.2 and 23.7% vs. control), alongside metabolomic signals indicating upregulation of linoleic acid metabolism and aromatic amino acid biosynthesis pathways. In contrast, TS substitution ≥50% reduced DMI and ADG, impairing feed utilization.

Partial replacement of CS with TS at 25% provides a practical, data-supported strategy to improve economic efficiency while maintaining productivity and promoting favorable rumen microbial-metabolic features. This feeding approach may be applicable in water-limited or double-cropping regions, where TS can enhance forage system sustainability without compromising heifer growth.