Performance of growing and finishing cattle supplemented with a slow-release urea product and urea Academic Article uri icon


  • Two growth trials were conducted to study the performance of Angus Crossbred steers supplemented with a slow-release urea product (Optigen 1200, O) and urea (U). The base diets were composed of corn silage alone during the growth period and corn silage plus cracked corn during the finishing period. Trial 1 consisted of 40 animals [272 4 kg body weight (BW)] individually fed the base diets and six treatments, which were based on corn silage alone and cracked corn supplemented with U or O to supply 50 (U50, O50) or 100% (U100, O100) of the ruminal N deficiency (U50, O50, U100, and O100) as predicted by the Cornell Net Carbohydrate and Protein System (CNCPS), or with U and O each supplying half of the CNCPS predicted N deficiency (U25O25). In trial 2, 120 pen-fed animals (241 7 kg BW) received the base diets and four combinations of U and O ( U100O0, U66O34, U34O66, and U0O100), which were designed to supply 100% of the ruminal N deficiency predicted by the CNCPS. In trial 1, no differences (P > 0.05) in performance were observed between the U100 and O100 treatments, but animals in the U50 treatment had a greater average daily gain (ADG) (P < 0.05) and feed conversion (P < 0.05) than animals on O50 treatment. In trial 2, combinations of U and O did not affect animal performance (P > 0.05). No differences were observed in carcass characteristics and predicted carcass and empty body fat for both trials (P > 0.05). We concluded there was no improvement in animal performance when urea was substituted by a slow-release urea/NH3 product at levels normally found in feedlot cattle diets. Key words: Cornell net carbohydrate and protein system, modeling, nutrition, growth, non-protein nitrogen

published proceedings


author list (cited authors)

  • Tedeschi, L. O., Baker, M. J., Ketchen, D. J., & Fox, D. G.

citation count

  • 38

complete list of authors

  • Tedeschi, LO||Baker, MJ||Ketchen, DJ||Fox, DG

publication date

  • December 2002