Animal Feed Science and Technology 99 (2002) 1–11 Performance and carcass characteristics of beef cattle fed diets containing silage from intercropped barley and annual ryegrass M.S. Zaman a,∗ , Z. Mir a , P.S. Mir a , A. El-Meadawy a , T.A. McAllister a , K.-J. Cheng b , D. ZoBell c , G.W. Mathison d a Agriculture and Agri-Food Canada, Lethbridge Research Centre, P.O. Box 3000, Lethbridge, Alberta, Canada T1J 4B b Faculty of Agricultural Sciences, 2357 Main Mall, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z4 c Department of Animal, Dairy and Veterinary Sciences, Utah State University, 4815 Old Main Hill, Logan, UT 84322-4815, USA d Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada T6G 2P5 Received 7 November 2001; received in revised form 24 April 2002; accepted 14 May 2002 Abstract A feeding trial was conducted to compare intercropped barley/annual ryegrass silage (B/RS) and barley silage (BS) on average daily gain (ADG), dry matter intake (DMI) and carcass character- istics of beef steers in a randomized complete block design experiment. Both B/RS and BS were prepared in plastic tube silos, ensiled for 168 days and then used in a feeding trial. Steers (n = 120) were housed in individual pens and fed a backgrounding diet containing 350 g steam-rolled barley grain (SBG) and 600 g kg -1 B/RS or 600 g kg -1 BS and 50 g kg -1 supplement until they weighed 445 kg, after which they were adapted to a finishing diet consisting of 860 g SBG and 100 g kg -1 B/RS or 100 g kg -1 BS and 40 g kg -1 supplement. Steer weight and back-fat depth (determined by ultra-sonography) were measured every 3 weeks. Steers were slaughtered when back-fat depth was greater than 7 mm and carcass data were obtained. Content of ADF in B/RS was lower (P< 0.05) than in BS, while protein content of the silages was similar. During backgrounding, ADG and DMI of steers fed B/RS (1.43, 8.5 kg per day) were higher (P< 0.05) than those fed BS (1.31, 8.0 kg per day) and feed conversion efficiency were similar between two groups of steers. Acetic:propionic ratio of rumen fluid from steers fed either B/RS or BS-based diets in the backgrounding trial were similar. Steers fed B/RS and BS diets had similar ADG, DMI and feed conversion efficiency in the finishing ∗ Corresponding author. Present address: Department of Animal and Range Sciences, Department 3-1, New Mexico State University, Box 30003, Las Cruces, NM 88003-8003, USA. Tel.: +1-505-646-4316; fax: +1-505-646-5441. E-mail address: szaman@nmsu.edu (M.S. Zaman). 0377-8401/02/$ – see front matter © 2002 Elsevier Science B.V. All rights reserved. PII:S0377-8401(02)00148-7