Valorization of Palm Kernel Meal as a Sustainable Feed Resource for Cattle: Chemical Composition and Ruminal Digestibility

Palm kernel meal (PKM), the solvent-extracted counterpart of palm kernel expeller (PKE), is generated in growing volumes as the palm oil industry expands, yet remains underexploited as a sustainable feed resource for ruminants. This study evaluated its nutritive value and valorization potential for cattle. Eight commercial PKM sources were analyzed and compared with PKE, corn gluten feed, and beet pulp by in vitro ruminal fermentation. Major nutrients were consistent across sources, with coefficients of variation ≤3.1% for organic matter, neutral detergent fiber (NDF, 765 g/kg dry matter), and crude protein (185 g/kg), whereas ether extract (24 g/kg) and the insoluble fractions varied more widely. Amino acid and fatty acid profiles were similar to those of PKE. The 48 h NDF digestibility (NDFD) was significantly higher in PKM (71.9%, p < 0.05) than PKE (53.7%) and did not differ from beet pulp (63.6%). The total digestible nutrients, estimated from composition and NDFD, were numerically higher in PKM (68.3%) than PKE (63.6%) despite its lower fat content and similar to beet pulp (70.3%), attributed to its higher truly digestible NDF. PKM is a reliable non-forage fiber source for ruminant diets, and its valorization as a secondary feed resource reduces dependence on conventional feed ingredients.