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

Background: 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. Methods: 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. Results: 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., Conclusion: 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.