NUTRITIONAL-EVALUATION OF POULTRY BY-PRODUCT MEAL AS A PROTEIN-SOURCEFOR RUMINANTS - EFFECTS ON PERFORMANCE AND NUTRIENT FLOW AND DISAPPEARANCE IN STEERS

We conducted three studies with steers to evaluate poultry by-product meal (PBM) as a supplemental N source for ruminants. An in situ study compared the solubility, degradation rate, and ruminal escape of PBM N with blood meal (BM), corn gluten meal (CGM), and soybean meal (SBM) N. Additionally, an 84-d growth study(n = 95, 228 +/- 5 kg BW) and a d igestion trial (6 x 6 Latin square) were conducted. The basal diet for the growth and digestion studies consisted of 49% corn silage, 36% co ttonseed hulls, and 15% supplement (DM basis). Sources of supplemental N (% of total supplemental N) were 100% SBM and 0, 25, 50, 75, and 10 0% PBM, with urea used to balance for N. In situ ruminal escape N (25. 2, 55.3, 86.7, and 98.9% for SBM, PBM, CGM, and BM, respectively) was greater (P < .05) for PBM than for SBM; however, a greater (P < .05) p roportion of BM and CGM N escaped ruminal degradation compared with PB M. Dry matter intake, ADG and gain/ feed increased linearly (P < .003) as PBM increased; however, no differences (P > .48) were observed in these variables for 100% PBM compared with 100% SBM. Duodenal N flow a nd small intestinal N disappearance increased linearly (P < .05) as PB M increased in the diet. Bacterial N flow to the small intestine was n ot affected (P > .19) by treatment; however, 100% SBM decreased (P < . 04) bacterial CP synthesis (g bacterial N/kg OM disappearance from the stomach) compared with 0 and 100% PBM. In vivo ruminal escape N of PB M and SBM was 40.6 and 13.7%, respectively. Ruminal NH3 N decreased li nearly (P < .001) as PBM increased. These data suggest that PBM can re place SBM as a source of supplemental N for steer calves that consume a diet based on corn silage and cottonseed hulls.