Influence of Rumen Protein Degradability and Supplementation Frequency on Ruminants Consuming Low-Quality Forage



Efficiency of Nitrogen Use in Lambs


An experiment was conducted to determine the influence of crude protein degradability (CPD) and supplementation frequency (SF) on efficiency of N use in lambs consuming low-quality forage.  Treatments included an unsupplemented control (CON) and degradable intake protein (DIP; 18% UIP) or undegradable intake protein (UIP; 60% UIP) provided daily, every 3 days, or every 6 days.  The DIP supplement was composed of soybean meal and the UIP supplement was composed of expeller processed soybean meal and blood meal.  The experiment was a nitrogen balance study using 7 wethers (36 ± 1 kg BW) in an incomplete 7 × 4 Latin square design with four 24-day periods.  The basal diet consisted of low-quality (5% CP) meadow hay.  Forage dry matter intake and nitrogen intake decreased (P < 0.05) linearly as SF decreased.  Dry matter intake, organic matter intake, nitrogen retention, nitrogen digestibility, and digested nitrogen retained were greater (P < 0.01) for supplemented wethers compared with CON with no difference (P > 0.10) due to CPD.  Nitrogen balance, dry matter intake, and organic matter intake decreased linearly (P < 0.05) as SF decreased.  Plasma urea (mM) was measured over a 6-day period with supplemented lambs having increased  (P < 0.01) plasma urea compared with CON.  Plasma urea linearly decreased (P < 0.01) as SF decreased.  Results suggest CP supplements consisting of 20 to 60% UIP can be effectively used by ruminants consuming low-quality forage without adversely affecting N efficiency, even when provided as infrequently as once every 6 days.


Click here for full journal article:            

Bohnert, D.W, C.S. Schauer, S.J. Falck, and  

T. DelCurto. 2002. Influence of rumen protein  

degradability and supplementation frequency on  

performance and nitrogen use in ruminants

consuming low-quality forage: Cow performance  

and efficiency of nitrogen use in wethers.

J. Anim. Sci. 80:1629-1637   (DWB PDF #10)  

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