Kim Sung Il, Park Sungkwon, Myung Jeong Hwan, Jo Young Min, Choi Chang Bon, Jung Keun Ki
Department of Animal Science, Gyeongbuk Provincial College, Yecheon 36830, Korea.
Department of Food Science and Biotechnology, Sejong University, Seoul 05006, Korea.
J Anim Sci Technol. 2021 Sep;63(5):1008-1017. doi: 10.5187/jast.2021.e84. Epub 2021 Sep 30.
This study was conducted to investigate the effect of different fattening periods on the growth performance, carcass characteristics, and economic traits of Holstein steers. Sixty Holstein steers (8.0 ± 0.28 months old) with an average body weight (BW) of 231.88 ± 2.61 kg, were randomly allocated to five different fattening period treatments: 20, 21, 22, 23, and 24 months (n = 12 in each treatment group). Final BW and average daily gain (ADG) did not differ among the treatment groups during the early fattening period. At the late stage of the fattening period, the final BW of steers in the 24-month treatment group (812.84 kg) was greater ( < 0.05) than that of steers in the 20-month treatment group (750.39 kg). During the same period, steers in the 20- and 21-month treatment groups had a significantly higher ( < 0.05) ADG than those in the 22-month treatment group. The highest ADG (1.36 kg/day) was found in the 20-month treatment group (1.36), followed by the 21- (1.33 kg/day), 22- (1.22 kg/day), 23- (1.21 kg/day), and 24- (1.14 kg/day) month treatment groups. The feed conversion ratio (FCR) increased as the fattening period increased, and the FCR was 12.88% lower in the 20-month treatment group than in the 24-month treatment group. However, no significant differences were detected in back-fat thickness, loin area, marbling score, and chemical characteristics (water, crude protein, and crude fat content) among the treatment groups. The composition of fatty acids including C18:0, C18:1, saturated fatty acids, unsaturated fatty acids, and poly-unsaturated fatty acids did not differ among the experimental groups. As the fattening period increased, production costs increased, resulting in a decrease in gross income. The gross income for steers in the 24-month treatment group was 35.8% and 23.5% lower than that for steers in the 20- and 21-month treatment groups, respectively. Taken together, the best performance, including the ADG, FCR, and gross income, was obtained when the fattening program of the Holstein steers lasted 20 months.
本研究旨在调查不同育肥期对荷斯坦公牛生长性能、胴体特征和经济性状的影响。选取60头荷斯坦公牛（8.0±0.28月龄），平均体重（BW）为231.88±2.61千克，随机分为五个不同育肥期处理组：20、21、22、23和24个月（每组n = 12）。在育肥前期，各处理组的最终体重和平均日增重（ADG）无差异。在育肥后期，24个月处理组公牛的最终体重（812.84千克）大于（<0.05）20个月处理组公牛的最终体重（750.39千克）。同一时期，20个月和21个月处理组的公牛ADG显著高于（<0.05）22个月处理组。ADG最高的是20个月处理组（1.36千克/天），其次是21个月处理组（1.33千克/天）、22个月处理组（1.22千克/天）、23个月处理组（1.21千克/天）和24个月处理组（1.14千克/天）。饲料转化率（FCR）随着育肥期的增加而升高，20个月处理组的FCR比24个月处理组低12.88%。然而，各处理组在背膘厚度、腰部面积、大理石花纹评分和化学特性（水分、粗蛋白和粗脂肪含量）方面未检测到显著差异。各实验组中包括C18:0、C18:1、饱和脂肪酸、不饱和脂肪酸和多不饱和脂肪酸在内的脂肪酸组成没有差异。随着育肥期的增加，生产成本增加，导致总收入下降。24个月处理组公牛的总收入分别比20个月和21个月处理组公牛低35.8%和23.5%。综上所述，当荷斯坦公牛的育肥期为20个月时，可获得包括ADG、FCR和总收入在内的最佳性能。
