Comparison of Urea and Biuret as Nitrogen Supplements to Low-quality Forage: Daily and Alternate Day Supplementation

Cow Performance

An experiment was conducted to determine the influence of supplemental non-protein N (NPN) provided daily (D) or every-other-day (2D) on cow performance.  Treatments included an unsupplemented control (CON) and a urea (28.7% CP) or biuret (28.6% CP) supplement provided D or 2D at 0700.  Eighty Angus x Hereford cows (540 ± 8 kg BW) in the last third of gestation were used to determine the effect of NPN source and supplementation frequency (SF) on cow performance.  The NPN treatments were formulated to provide 90% of the estimated degradable intake protein requirement.  The supplemented treatments received the same amount of supplemental N over a 2-d period; therefore, the 2D treatments received double the quantity of supplemental N on their respective supplementation day compared with D treatments.  Pre-  and post-calving (within 14 d and 24 h after calving, respectively)  cow weight and body condition score change  were more positive (P < 0.05) for supplemented groups compared with CON.  These results suggest that supplements containing urea or biuret as the primary source of supplemental N can be effectively used by cows consuming low-quality forage, even when provided every-other-day.

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Currier, T.A., D.W. Bohnert, S.J. Falck, and S.J. Bartle. 2004.  Daily and alternate day supplementation of urea or biuret to ruminants consuming low-quality forage: Effects on cow performance and the efficiency of nitrogen use in wethers.  J. Anim. Sci.82:1508-1527. (DWB PDF#2)