108 Supplemental tannin has improved daily weight gain and gain efficiency in feedlot cattle (Barajas et al. 2010, 2011) owing to decreased ruminal protein degradation, resulting in greater metabolizable amino acids supply (Min et al. 2003), and the decreased methane production (Goel and Makkar 2012). However, with conventional feeding practices, limitations on metabolizable amino acid supply in feedlot cattle is unlikely except during the receiving and initial growing phases (Zinn and Shen 1998, Zinn et al. 2007). The effects of supplemental tannins on mitigation of methane production were observed in cattle fed high fiber diets (Woodward et al. 2004, Puchala et al. 2005), whereas conventional feedlot finishing diets have a minimal fiber (8–9% forage in diets; Vasconcelos and Galyean et al. 2007). Nevertheless, in recent years increased amounts of dry distiller grains with solubles (DDGS) were incorporated into finishing diets as a partial replacement for grain. Due to the high fiber content of DDGS, this replacement resulted in increased methane production as a proportion of digestible energy intake (Luebbe et al. 2011, Carrasco et al. 2013). There is limited information on the effects of tannins supplementation on growth performance and carcass characteristics of yearling cattle fed finishing diets contained DDGS. The objective of the present experiment was to determine the effect of tannins supplementation on growth performance, dietary energetics and carcass characteristics in yearling steers fed a finishing diet containing DDGS. Finishing diets containing 15% of DDGS were fed to 150 crossbred steers for 152-d experiment following all procedures involving animal care and management were in accordance with and approved by the University of California, Davis, Animal Use and Care Committee. Cattle originated from southeast Texas and were received Indian Journal of Animal Sciences 86 (1): 108–111, January 2016/Short communication Influence of tannins supplementation on growth performance, dietary net energy and carcass characteristics of yearling steers fed finishing diet containing dried distillers grains with solubles CARLOS R RIVERA-MÉNDEZ 1 , ALEJANDRO PLASCENCIA 2 , NOEMÍ TORRENTERA 3 and RICHARD A ZINN 4 Department of Animal Science, University of California, Davis 95616 USA Received: 13 April 2015; Accepted: 8 June 2015 Key words: Carcass, Dietary energy, Feedlot, Finishing, Tannins at the University of California Desert Research Center, El Centro. Upon arrival, cattle were vaccinated for bovine rhinotracheitis-parainfluenza 3 , clostridials, treated for parasites, injected subcutaneously with 500,000 IU vitamin A, and 1,200 mg ceftiofur , branded, ear-tagged, and implanted with Revalor-IS. Bull steers were castrated and horns, if present, were tipped. During initial 49-d adaptation period all steers were fed receiving and transition diets. On d 28 of the transition period steers weighed and given their vaccine booster shots. Steers were then blocked on day 28 th by weight and randomly assigned within weight groupings to 30 pens, 5 steers/pen and 10 pens/treatment. Subsequently, all steers received the same basal finishing diet (Control diet, Table 1) for 14 d prior to initiation of the experiment which lasted 152 days. Pens were 78 m 2 with 33 m 2 of overhead shade, automatic waterers, and fence- line feed bunks. Dietary treatments consisted of a steam- flaked corn-based growing-finishing diet (Table 1) supplemented with 0, 0.32, and 0.64% CT (70% condensed tannin;CT) which correspond to 0, 2.2 and 4.4 g of condensed tannins/kg DM. Diets were prepared at weekly intervals and stored in plywood boxes located in front of each pen. Steers were allowed ad lib. access to experimental diets. Fresh diet was provided twice daily. Feed and refusal samples were collected daily for DM analysis, which involved oven drying the samples at 105°C until constant weight (method 930.15, AOAC 2000). Fifty days after experiment began, all steers were again injected subcutaneously with 500,000 IU vitamin A and implanted with Revalor-S. For estimation of dietary net energy, energy gain (EG) was calculated by the equation: EG = ADG 1.097 0.0557W 0.75 , where EG, daily energy deposited (Mcal/d); W, mean shrunk BW (kg; NRC 1984). Maintenance energy (EM) was calculated by the equation: EM = 0.077W 0.75 (NRC 1984). Dietary NE g was derived from NE m by the equation: NE g = 0.877 NE m - 0.41 (Zinn 1987). Dry matter intake is related to energy requirements and dietary NE m according to the equation: DMI = EM/ NE m + EG/ (0.877NE m - 0.41), and can be resolved for estimation of Present address: 1 PhD student (crriveram@hotmail.com), Consejo Nacional de Ciencia y tecnología, México. 2,3 Senior Scientist (alejandro.plascencia@uabc.edu.mx, torrenteranoemi @uabc.edu.mx) Instituto de Investigaciones en Ciencias Veterinarias, Universidad Autónoma de Baja California, Mexicali, México. 4 Professor (razinn@ucdavis.edu).