Effects of supplemental protein source and metabolizable energy intake on nutritional status in pregnant ewes

Two experiments were conducted to evaluate effects of supplemental protein source and ME intake (Exp. 1) on ewe nutritional status during pregnancy. Forty-two mature Targhee ewes were allotted randomly in Exp. 1 to one of six treatments (n = 7) using a 2 x 3 factorial arrangement. Ewes were individually fed chopped barley straw and supplements containing either urea (U), soybean meal (SBM), or blood meal (BM) plus SBM during the 84-d experiment. Straw and supplement intakes were adjusted to meet either 80 or 100% of ME requirements. In Exp. 2, 30 pregnant Targhee ewes that were allotted randomly to one of three groups (n = 10) were individually fed protein supplements similar to those in Exp. 1 and had group access to long-stem barley straw. In Exp. 1, ewes fed BM + SBM gained more (P less than .05) weight, lost less (P less than .05) body condition, and had increased (P less than .05) wool fiber length compared with ewes fed U; SBM ewes were intermediate (P less than .05) in response. Ewes fed BW + SBM had increased (P less than .05) blood urea N and albumin concentrations compared with ewes fed U. Metabolizable energy intake did not affect (P greater than .05) ewe performance or serum metabolite concentrations. Ewes fed BM + SBM in Exp. 2 gained more (P less than .05) weight than ewes fed either SBM or U, and ewes fed SBM lost less weight (P less than .05) than ewes fed U.(ABSTRACT TRUNCATED AT 250 WORDS)