title: Supplemental protein and energy for beef cows consuming endophyte-infected tall fescue.
abstract: Effects of energy and protein supplementation of endophyte (Acremonium coenophialum)-infected (E+) and noninfected (E-) tall fescue (Festuca arundinacea Schreb.) on forage intake, digestibility, N flow to the small intestine, and cow-calf productivity was evaluated in two experiments. In Exp. 1, 10 ruminally and duodenally cannulated steers were fed either E- or E+ hay with four supplements or E- or E+ hay unsupplemented. Four supplements formulated with either cracked corn or soybean hulls with 100 or 200 g/d of ruminally undegraded intake protein (UIP) were compared. Levels of UIP were varied by adding soybean meal or blood meal. Hay OM intake was not affected (P > .20) by source of energy of level of UIP; however, intake of E- was greater (P < .05) than that of E+. True ruminal OM digestion tended to be greater (P < .12) for steers fed 200 g/d of UIP than for steers fed 100 g/d. Steers receiving 200 g/d of UIP had increased (P < .10) total N flow to the duodenum compared with steers receiving 100 g/d but similar (P > .20) microbial efficiencies. In Exp. 2, 30 cows (average initial BW 459 +/- 26 kg) and their calves (average initial BW 74 +/- 5 kg and 74 +/- 5 d of age) grazed an 8.1-ha E+ pasture from late May to late July. Cows were individually fed supplements used in Exp. 1 each day. Cows that received cracked corn lost .10 kg/d when fed 100 g/d of UIP but gained .33 kg/d when fed 200 g/d. Cows fed soybean hulls and 100 g/d of UIP gained .07 kg/d, whereas cows provided 200 g/d lost .10 kg/d. Calves nursing cows supplemented with 100 g/d of UIP gained more (P < .08) BW because of increased (P < .07) milk consumption and slightly greater (P < .19) forage intake than calves nursing cows supplemented with 200 g/d of UIP.
authors.affiliation: Department of Animal Sciences, University of Missouri, Columbia 65211, USA.
authors.forename: J C
authors.initials: JC
authors.lastname: Forcherio
authors.forename: G E
authors.initials: GE
authors.lastname: Catlett
authors.forename: J A
authors.initials: JA
authors.lastname: Paterson
authors.forename: M S
authors.initials: MS
authors.lastname: Kerley
authors.forename: M R
authors.initials: MR
authors.lastname: Ellersieck
mesh_terms: D000164:Acremonium / Q000302:isolation & purification* / Q000502:physiology; D000818:Animals; D002417:Cattle / Q000378:metabolism / Q000502:physiology*; D004044:Dietary Proteins / Q000008:administration & dosage*; D004063:Digestion / Q000502:physiology; D004386:Duodenum / Q000378:metabolism / Q000502:physiology; D004435:Eating / Q000502:physiology*; D002149:Energy Intake / Q000502:physiology; D004734:Energy Metabolism / Q000502:physiology*; D004879:Ergotamines / Q000032:analysis; D008297:Male; D009584:Nitrogen / Q000378:metabolism; D006109:Poaceae / Q000737:chemistry / Q000382:microbiology*; D012417:Rumen / Q000378:metabolism / Q000502:physiology; D013025:Glycine max / Q000592:standards; D003313:Zea mays / Q000592:standards
chemical_list: D004044:Dietary Proteins; D004879:Ergotamines; C076760:ergovaline; D009584:Nitrogen