Effect of Rumen Protected Methionine and α-Tocopherol on Growth Performance, Carcass Characteristics, and Meat Composition of Late Fattening Hanwoo Steer in High-Temperature Seasons

SIMPLE SUMMARY: Over the past 100 years, the average temperature in Korea has risen by 1.8 ℃, more than double the world average (0.75 ℃). High temperatures in summer can cause a decrease in feed intake, body weight gain, rumen mobility, and liver function. This study was conducted to investigate the effects of rumen-protected methionine and α-tocopherol (RPMT) on the growth performance, carcass characteristics, and meat composition of late fattening Hanwoo steers in high-temperature seasons. In this study, supplementations with RPMT are considered to be beneficial to average daily gain, feed conversion ratio, and Commission Internationale de l’Eclairage color stability without adversely affecting the feed intake of the late fattening Hanwoo steers in high-temperature seasons. Thus, supplementations of RPMT has desirable effects on the performance traits in beef cattle and prevents oxidation of longissimus muscle. Henceforward, further studies with more animals and increase the mounts of addition are needed. ABSTRACT: This study was conducted to investigate the effects of rumen-protected methionine and α-tocopherol (RPMT) on growth performance, carcass characteristics, and meat composition of late fattening Hanwoo steers in high-temperature seasons. Fourteen steers were randomly assigned to one of two diets; control (commercial concentrate) and treatment (commercial concentrate + 20 g of RPMT). Average daily gain was 34% higher in the treatment group than in the control group; however, there was no significant difference due to the small number under investigation. Feed conversion ratio was lower in the treatment group than in the control group (p < 0.05). Supplementation of RPMT had little effect on the fatty acid composition of longissimus muscle. Metmyoglobin in the longissimus muscle was significantly lower in treatment group compared to the control group at the ninth day of storage (p < 0.05). The redness of the longissimus muscle was higher in the treatment group than in the control group on day 9 of storage (p < 0.01). Thus, the results suggest that RPMT have positive effects on growth performance, and Commission Internationale de l’Eclairage color stability in the longissimus muscle of late fattening Hanwoo steers in high-temperature seasons.