CONCLUSION

This study demonstrated that locally available agricultural and agro-industrial by-products can be effectively utilized to formulate nutritionally balanced and economically viable concentrate rations for cattle raised under smallholder conditions in Bangkalan Regency, Indonesia. Progressive replacement of tofu waste with cassava waste produced predictable changes in nutrient composition, characterized by reduced CP and EE contents and increased NFE and fiber fractions, while maintaining relatively stable dietary energy density. Consequently, all four concentrate formulations supported comparable digestibility, LWG, FCR, and IOFC, indicating that varying proportions of cassava waste and tofu waste can be used without compromising productive performance.

Breed exerted a more pronounced influence than dietary treatment on nutrient intake and productive responses. Madrasin bulls consistently exhibited greater DMI, higher digestible nutrient intake, superior fiber utilization, and greater LWG and IOFC than Madura bulls. These findings confirm the superior growth potential and economic advantages of crossbred cattle under improved feeding systems. Nevertheless, the ability of indigenous Madura cattle to maintain satisfactory performance under the same nutritional conditions highlights their continued importance for sustainable cattle production in resource-limited, harsh tropical environments.

A major strength of this study lies in its integrated evaluation of feed composition, intake behavior, digestibility, growth performance, and economic returns under realistic communal village production conditions rather than under research station environments. This approach enhances the applicability of the findings to practical smallholder systems. In addition, the direct comparison between pure Madura and Madrasin bulls that receive identical locally formulated diets provides novel information on breed-specific responses to agricultural by-product-based feeding strategies.

In conclusion, concentrate formulations incorporating cassava waste, tofu waste, and copra meal can effectively support productive and profitable cattle production under smallholder conditions. While Madrasin bulls exhibited superior productive and economic performance, the conservation of indigenous Madura cattle remains essential because of their unique adaptive characteristics and genetic value. Sustainable cattle development in Indonesia will therefore require feeding innovations that maximize the use of local by-products while simultaneously preserving valuable indigenous cattle genetic resources.