Journal of Animal Science and Technology
Korean Society of Animal Science and Technology

Effects of Energy Levels on Growth Performance, Carcass Characteristics, and Fatty Acid Composition of Holstein Steers at different slaughter ages

Sung Il Kim1,*, Sungkwon Park2, Hyun Soo Lee3, Ji Hong Lee1, Do Hyung Kim1, Jung Hwan Myung3, Keun Ki Jung4
1Department of Animal Science, Gyeongbuk Provincial College, Yecheon 36830, Korea.
2Department of Food Science and Biotechnology, Sejong University, Seoul 05006, Korea.
3Deahan Livestock & Feed CO, Incheon 22300, Korea.
4Moksan Hanwoo Research Institute, Gyeongsan 38507, Korea.
*Corresponding Author: Sung Il Kim, Department of Animal Science, Gyeongbuk Provincial College, Yecheon 36830, Korea, Republic of. E-mail:

© Copyright 2023 Korean Society of Animal Science and Technology. This is an Open-Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License ( which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Received: Feb 09, 2023; Revised: Apr 10, 2023; Accepted: May 16, 2023

Published Online: May 17, 2023


We investigated the effect of energy levels on growth performance, carcass characteristics, and fatty acid composition of Holstein steers at different slaughter ages. Forty Holstein steers with an average body weight (BW) of 234.21 kg ± 7.42 and 7.78 ± 0.22 months were randomly allocated to two experimental groups; a 22-month-old experimental group and a 24-month-old experimental group. Total digestible nutrients (TDN) for each group were set to 70% (T1) and 72% (T2) during fattening phase and 74% (T3) and 76% (T4) for the finishing phase, respectively. No difference was observed in the final BW between the experimental groups during the fattening phase. However, in the finishing phase, the final BW of T4 (820.31 kg) group was significantly higher than that of T1 (745.57 kg; <italic>p</italic> &lt; 0.05 ). The average daily gain (ADG) of T2 group in the finishing phase and overall period were 1.27 kg and 1.26 kg, respectively, which were significantly higher than those of T1 (1.11 kg and 1.12 kg; <italic>p</italic> &lt; 0.05). The feed conversion ratio (FCR) and TDN conversion ratio of T2 group in the finishing phase also decreased by 10.23% and 7.73%, respectively, compared to those of T1. The cold carcass weight of T4 group was significantly higher (<italic>p</italic> &lt; 0.05) than that of T1, whereas back fat thickness, longissimus area, and marbling score were not significantly different among groups. No differences were observed in physicochemical characteristics of the carcass including moisture, crude protein, and crude fat content among groups. However, the composition of fatty acids differed significantly between the groups. The content of C18:0 was significantly lower (<italic>p</italic> &lt; 0.05) in T4 than in T1 group, and the content of C18:2 was higher in T4 than in T1 and T3 (<italic>p</italic> &lt; 0.05). Therefore, feeding Holstein steers at a high-energy feeding level during the fattening and finishing phases improves ADG and reduces the slaughter age from 24 months to 22 months.

Keywords: Holstein steer; Average daily gain; Feed conversion ratio; Fatty acid composition