Effects of Supplemental Dried Distillers Grains or Soybean Hulls on Growth and Internal Parasite Status of Grazing Lambs1

The objectives of this study were to determine the effects of supplementation of grazing lambs with dried distillers grains with solubles (DDGS) or soybean hulls (SBH) on growth rate and nematode-parasite status. Over the course of four experiments in consecutive years, 312 lambs were grazed on the same four or six paddocks. Grazing lambs were allotted to one of three supplementation treatments: 1) control, no supplementation (CONT), 2) DDGS, or 3) SBH (Exp. 3 and 4 only). Supplemental DDGS improved (P < 0.01) ADG when compared to CONT, and SBH supplemented lambs were intermediate. An analysis comparing CONT vs. DDGS supplementation across all four experiments revealed a reduction in anthelmintic-treatment rate required when DDGS were supplemented (81.2 percent vs. 30.1 percent for CONT and DDGS, respectively; P < 0.01). Measures of FAMACHA© score, packed-cell volume (PCV), and fecal-egg count (FEC) were recorded in weeks 3, 5, and 10. An analysis comparing just CONT and DDGS supplementation across all four experiments revealed that DDGS supplementation reduced (P < 0.01) FAMACHA score in weeks 3, 5, and 10, but only reduced FEC in week 3 compared to CONT lambs. Supplementation of grazing lambs with DDGS in this study allowed for increased growth, reduced anthelmintic-treatment rate, and reduced risk of becoming anemic as a result of internal parasites.