Partial replacement of concentrate with fermented cassava products in Thai native × Lowline Angus cattle: effects on nutrient utilization and rumen fermentation

Context In tropical regions where cassava (Manihot esculenta) is widely cultivated, its byproducts (tops and pulp) represent underutilized feed resources despite their nutritional potential. Aim The study evaluated the effects of replacing concentrate with dried cassava tops fermented cassava pulp (CtFCp) on feed intake, nutrient digestibility, and rumen fermentation in growing 75% Thai native × 25% Lowline Angus crossbred cattle. Methods Twelve heifers (initial bodyweight (BW) 97 ± 18.10 kg) were assigned to three dietary treatments in a completely randomized design: 100% concentrate (CON), 67% concentrate + 33% CtFCp (CtFCp-33), and 33% concentrate + 67% CtFCp (CtFCp-67), on a dry-matter (DM) basis. Data were analyzed using one-way ANOVA, with treatment means compared by Duncan’s multiple-range test. Key results Total feed and organic-matter (OM) intakes were not affected by dietary treatment. However, crude protein (CP), DM, neutral detergent fiber (NDF), acid detergent fiber (ADF), and total digestible nutrients (TDN) were significantly affected. The CON treatment showed greater digestibility and TDN than did CtFCp-67, whereas CtFCp-33 exhibited intermediate values and did not differ significantly from either treatment. These results indicate that a higher CtFCp inclusion level reduces nutrient utilization. Rumen fermentation parameters showed increased total volatile fatty acids (VFA) and butyrate, but decreased acetate and propionate 4 h post-feeding in CtFCp-67. At 0 h post-feeding, treatments CtFCp-33 and CtFCp-67 produced more methane (CH4) than did CON. However, at 4 h post-feeding, CtFCp-33 produced significantly more CH4 than did both CON and CtFCp-67. Conclusion The current study found that replacing 67% of the concentrate with CtFCp enhanced the digestibility of NDF and TDN. Furthermore, incorporating CtFCp into cow feed can reduce feed costs while utilizing agricultural by-products. Moreover, further research is warranted to assess long-term growth performance and economic viability. Implications Replacing 67% of concentrate with CtFCp may enhance nutrient digestibility, reduce feed costs, and support sustainable cattle production.