EVALUATION OF DRIED DISTILLERS GRAINS COMPARED TO BARLEY IN EXTENSIVE GRAZING SCENARIOS FOR STOCKER CATTLE
Three experiments were conducted to determine the effects of dry distillers grains (DDGS) on calf performance, forage utilization, and production costs. In addition, a digestibility trial was conducted using ram lambs to determine the effects of supplement on nutrient digestibility and intake. In 3 field grazing trials, 54 crossbred yearling beef calves (mean BW±SD; 258.1±7.3kg) were stratified by body weight (BW) and randomly allocated to 1 of 3 replicated (n=2) supplement strategies. Calves were managed on fall stockpiled crested wheatgrass pasture (OMD=48.1%, CP=6.2% (DM)) in experiment one (EXP 1) and summer pasture in experiment three (EXP 3) (OMD=57.0%, CP=14.4% (DM)). For experiment two (EXP 2) the same calves form EXP 1 were managed on a bale grazing (OMD=45.3%, CP=7.1% (DM)) program on dormant pasture. EXP 1 supplement treatments were (1) 70% barley + 30% canola meal (CONT); (2) 70% barley + 30% DDGS (70:30); and (3) 100% DDGS. EXP 2 and EXP 3 supplementation treatments were (1) 100% barley (CONT); (2) 50% barley + 50% DDGS (50:50); and (3) 100% DDGS. Forage utilization was measured for all grazing trials using the herbage weight disappearance method. Calf BW was measured at start and end of trial and every 14 d throughout. There was no effect (P>0.05) of supplementation on forage utilization in EXP 1 or EXP 2. Pasture utilization was greater (P=0.04) in EXP 3 for CONT and 50:50 supplement strategies compared to DDGS supplemented calves. There was no effect (P>0.05) of supplement strategy on calf performance in terms of body weight change in all 3 field grazing studies. Costs per calf per d in EXP 1 were $0.80, $0.79 and $0.77 for DDGS, 70:30 and CONT, respectively. Costs per calf per d in EXP 2 were $1.53, $ 1.51, and $1.53 for DDGS, 50:50 and CONT, respectively. Costs per calf per d for EXP 3 were $1.84, $1.78, and $1.71 for DDGS, 50:50 and CONT, respectively. In experiment four (EXP 4), 24 Suffolk ram lambs (mean BW±SD; 43.5±5 (kg)) were fed a grass legume hay (OMD=54.17%, CP=7.17% (DM)) and supplemented with either (1) 100% DDGS; (2) 50% barley and 50% DDGS; (3) 100% barley (CONT). Forage intake and apparent total tract digestibility were measured. Forage intake was not (P>0.05) affected by supplementation strategy. Digestibility of CP (P=0.01) and ADF (p=0.02) were significantly higher for DDGS supplemented calves, compared barley supplemented calves. However, organic matter digestibility (OMD) and dry matter digestibility (DMD) were not different between supplement strategies. The results of all 4 experiments suggest that DDGS can be used as a suitable supplement for growing beef calves or sheep in extensive pasture scenarios, while consuming grass-legume hay. DDGS had similar effects on calf performance, forage utilization, and digestibility. Because of this, the inclusion of DDGS as a supplement for ruminants will depend on the initial price of the supplement.
Wheat DDGS, backgrounding, extensive grazing, barley, sheep
Master of Science (M.Sc.)
Animal and Poultry Science