Adequate but not excessive dietary energy supply is crucial for growth and productivity in cattle. This study aimed to evaluate the effects of three incremental changes in metabolizable energy (ME) levels in concentrate mixes, i.e., low (LEC, 10.4 MJ/kg DM), medium (MEC, 10.8 MJ/kg DM), and high (HEC, 11.0 MJ/kg DM), on growth performance and comprehensive physiological parameters in Hanwoo steers. Thirty steers, averaging 499 ± 38.0 kg, were randomly allocated to one of the treatments. Each steer received up to 8 kg of concentrate mix, with ad libitum access to tall fescue. Body weights were measured every four weeks. In week 12, rumen samples were collected, followed by fecal and blood samples. The HEC group exhibited a 16.5% higher average daily gain compared to the other groups (p = 0.035). Forage and total dry matter (DMI) were 46% and 12% lower in the HEC group (p < 0.001). Fiber digestibility increased with energy content (p < 0.05). Total volatile fatty acid and the acetate-to-propionate ratio decreased in the HEC group (p < 0.001), while blood creatinine concentration increased (p < 0.01). In conclusion, feeding Hanwoo steers with a high-energy concentrate mix (up to 11.0 MJ ME/kg DM) improved growth and feed efficiency without compromising rumen health.

Adequate but not excessive dietary energy supply is crucial for growth and productivity in cattle. This study aimed to evaluate the effects of three incremental metabolizable energy (ME) levels in concentrate mixes: low (LEC, 10.4 MJ/kg DM), medium (MEC, 10.8 MJ/kg DM), and high (HEC, 11.0 MJ/kg DM) on growth performance and comprehensive physiological parameters in Hanwoo steers. Thirty steers, averaging 499 ± 38.0 kg, were randomly allocated to one of the treatments. Each steer received up to 8 kg of concentrate mix, with ad libitum access to tall fescue. Body weights were measured every four weeks. In week 12, rumen samples were collected, followed by fecal and blood samples. The HEC group exhibited a 16.5% higher average daily gain compared to the other groups (p = 0.035). Forage and total dry matter (DMI) were 46% and 12% lower in HEC (p < 0.001). Fiber digestibility increased with energy content (p < 0.05). Total volatile fatty acid and the acetate-to-propionate ratio decreased in HEC (p < 0.001), while blood creatinine concentration increased (p < 0.01). In conclusion, feeding Hanwoo steers with a high-energy concentrate mix (up to 11.0 MJ ME/kg DM) improved growth and feed efficiency without compromising rumen health.

Detecting feeding behavior in cattle is important but can be cumbersome when done manually. This study aimed to validate two wearable biosensors─RumiWatch noseband (RW) and Nedap SmartTag Neck (ND)—for monitoring feeding behavior in Hanwoo cattle. Specifically, we assessed the agreement between feeding behaviors recorded by RW and ND and those obtained manually through video observation (VO), focusing on eating time (ET) and ruminating time (RT). Three Hanwoo cows (540 ± 24.12 kg) were fitted with both sensors and continuously video-recorded for three consecutive days. Data from both 1 h (n = 216) and 24 h (n = 9) summaries were used to compare RW with VO, while ND data were analyzed only at the 24 h level. The RW showed strong agreement with VO for RT, with concordance correlation coefficients (CCC) of 0.98 (1 h) and 0.95 (24 h). In contrast, RT from ND showed poor agreement with VO (CCC = 0.12 for 24 h). Least squares means for RT (min/24 h) did not differ between VO (460 min) and RW (461 min), but ND significantly underestimated RT (211 min; p < 0.001). Both RW and ND performed poorly in detecting ET (CCC = 0.05 for RW and −0.15 for ND at 24 h). However, when time spent on both eating and other jaw movements was combined in VO, the combined time did not differ significantly from ET reported by RW (441 min vs. 454 min; p > 0.05), with improved agreement (CCC = 0.62). Cow, day, and their interaction had no significant effect on the deviation between VO and RW for RT (p > 0.05). Overall, these results indicate that RW accurately detects RT but tends to overestimate ET, whereas ND significantly underestimates both ET and RT with poor concordance in Hanwoo cows.

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.