Effects of feeding ethanol on growth performances, carcass characteristics, and lipid metabolism of finishing Korean cattle (Hanwoo) steers

Objective: The purpose of this study was to determine the effects of feeding ethanol on growth performances, carcass characteristics, and lipid metabolism of finishing Korean cattle (Hanwoo) steers. Methods: Thirty (30) Hanwoo steers (average 25.1 months of age, body weight 660.1 kg) were assigned to three treatments: control (0% ethanol), E-3 (1.44% ethanol for 3 months), or E-5 (0.72% ethanol for 2 months followed by 1.44% ethanol for 3 months). The animals were allotted by treatment group into six pens and fed concentrate and perennial ryegrass. Ethanol (30%, v/v) was supplemented into drinking water twice a day to meet final concentrations based on average water consumption of finishing Hanwoo steers. Results: There were no statistical differences among the groups in final body weight, average daily gain, or carcass yield grade indices such as cold carcass weight, fat thickness, and loin area. The marbling score tended (p = 0.228) to increase with the highest score (6.7) in the E-5 group followed by 6.3 and 6.0 in E-3 and control groups, respectively. The appearance frequencies of quality grades of $1^{{+}{+}}$ (the best), $1^{+}$, 1, and 2, were; 30%, 50%, 0%, and 20% for control, 10%, 80%, 10%, and 0% for E-3, and 10%, 80%, 0%, and 10% for E-5 groups, respectively, indicating improvements of quality grades by feeding ethanol. Concentrations of serum glucose tended to decrease whereas those of insulin and non-esterified fatty acid to increase by feeding ethanol (E-3 and E-5; p>0.05). Conclusion: Feeding ethanol directly into drinking water of finishing Hanwoo steers stimulated lipogenesis in intramuscular adipose tissue (marbling) and thereby improved carcass quality grade. The serum metabolites results supported the hypothesis of lipolysis of existing adipose tissue, such as abdominal fats, and lipogenesis in intramuscular adipocytes.