Valorization of cassava-based agro-industrial byproducts as ensiled total mixed fiber for sustainable roughage replacement in early-lactating dairy cows.

Abstract

Background and aim: Sustainable utilization of agro-industrial byproducts offers an opportunity to reduce feed costs and dependence on conventional forages in tropical dairy production. Cassava pulp and cassava bioethanol waste are abundant residues with potential as alternative roughage sources, yet their application as ensiled total mixed fiber (TMF) in early-lactating dairy cows has not been systematically evaluated. This study investigated the effects of ensiled TMF formulated with cassava pulp or cassava bioethanol waste as complete roughage replacements for guinea grass on feed intake, nutrient digestibility, rumen fermentation, blood metabolites, milk yield, and milk composition in early-lactating dairy cows.

Materials and methods: Eighteen multiparous Holstein Friesian crossbred cows (25 ± 15 days in milk) were allocated to three dietary treatments in a randomized complete block design (n = 6/group): fresh guinea grass (control), ensiled TMF containing cassava pulp (TMFc), or ensiled TMF containing cassava bioethanol waste (TMFe). All diets were offered ad libitum with a roughage-to-concentrate ratio of 40:60 over a 90-day feeding period. Feed intake, apparent nutrient digestibility, rumen fermentation characteristics, blood urea nitrogen, milk yield, and milk composition were determined.

Results: Cows fed TMFe showed significantly greater dry matter intake (15.6 ± 0.61 kg/day), nutrient intake, and metabolizable energy intake (36.10 ± 1.26 Mcal/day) than those receiving guinea grass (p < 0.01). Apparent digestibility of dry matter, organic matter, crude protein, neutral detergent fiber, and acid detergent fiber remained unchanged among treatments (p > 0.05). Ruminal pH and temperature were maintained within physiological ranges. At 4 h post-feeding, TMFc increased blood urea nitrogen (21.2 ± 1.89 mg/dL; p = 0.047), ruminal ammonia nitrogen (14.24 ± 0.35 mg%; p = 0.001), and butyrate production, whereas the control diet produced higher propionate concentrations (p = 0.044). Milk composition was unaffected by dietary treatment, while TMFc showed a tendency toward greater milk yield (15.5 ± 0.82 kg/day; p = 0.069).

Conclusion: Ensiled TMF formulated from cassava-based agro-industrial byproducts can effectively replace conventional guinea grass without compromising nutrient digestibility, rumen stability, or milk composition in early-lactating dairy cows. Cassava bioethanol waste-based TMF improved voluntary feed intake and energy supply, whereas cassava pulp-based TMF enhanced ruminal nitrogen metabolism and tended to increase milk yield. These findings demonstrate the potential of cassava-derived byproducts as sustainable alternative roughage resources that support circular bioeconomy principles and improve feed resource utilization in tropical dairy production systems.