Inclusion of Unqualified Cacao Pod in Mineral Feed Block: A Novel Strategy to Improve Rumen Fermentation and Mitigate Methane Emissions in Beef Cattle.

Objective: This study aimed to evaluate the effects of incorporating unqualified cacao pod powder into beef cattle diets on nutrient digestibility, rumen fermentation, greenhouse gas emissions, and blood metabolites.

Methods: A 4 × 4 Latin square design was used with four of Brahman × Thai native crossbred steers (207.1 ± 45.1 kg BW). Treatments included; T1: a control (no supplement), T2: supplemented with 50 g/day of cacao powder, T3: supplemented with mineral block containing cacao powder and T4: both supplemented with 50 g/day of cacao powder and mineral block containing cacao powder.

Results: Results showed no significant effect on feed intake, but polyphenol and tannin intake increased (P < 0.01). Apparent digestibility of dry matter, organic matter, protein, and both detergent fiber increased with cacao supplementation (P < 0.01). Rumen pH, total volatile fatty acid, and acetate concentrations increased, while methane and carbon dioxide emissions were reduced (P < 0.01). Blood urea nitrogen levels decreased (P < 0.05), while concentration of white blood cell, red blood cell, hemoglobin and lymphocyte percentage remained unchanged. The neutrophil percentage tended to decrease, as same as, the neutrophil to lymphocyte ratio in the supplemented groups (P = 0.06 and P = 0.08, respectively).

Conclusion: These findings suggest that unqualified cacao pods can enhance nutrient utilization and mitigate enteric methane emissions, offering a sustainable strategy for valorizing cacao byproducts in ruminant production.