title: Truly Absorbed Microbial Protein Synthesis, Rumen Bypass Protein, Endogenous Protein, and Total Metabolizable Protein from Starchy and Protein-Rich Raw Materials: Model Comparison and Predictions.
abstract: This study was carried out to measure truly absorbed microbial protein synthesis, rumen bypass protein, and endogenous protein loss, as well as total metabolizable protein, from starchy and protein-rich raw feed materials with model comparisons. Predictions by the DVE2010 system as a more mechanistic model were compared with those of two other models, DVE1994 and NRC-2001, that are frequently used in common international feeding practice. DVE1994 predictions for intestinally digestible rumen undegradable protein (ARUP) for starchy concentrates were higher (27 vs 18 g/kg DM, p < 0.05, SEM = 1.2) than predictions by the NRC-2001, whereas there was no difference in predictions for ARUP from protein concentrates among the three models. DVE2010 and NRC-2001 had highest estimations of intestinally digestible microbial protein for starchy (92 g/kg DM in DVE2010 vs 46 g/kg DM in NRC-2001 and 67 g/kg DM in DVE1994, p < 0.05 SEM = 4) and protein concentrates (69 g/kg DM in NRC-2001 vs 31 g/kg DM in DVE1994 and 49 g/kg DM in DVE2010, p < 0.05 SEM = 4), respectively. Potential protein supplies predicted by tested models from starchy and protein concentrates are widely different, and comparable direct measurements are needed to evaluate the actual ability of different models to predict the potential protein supply to dairy cows from different feedstuffs.
authors.affiliation: †Department of Animal Science, Ferdowsi University of Mashhad, 9177948978 Mashhad, Iran.
authors.forename: Ehsan
authors.initials: E
authors.lastname: Parand
authors.affiliation: †Department of Animal Science, Ferdowsi University of Mashhad, 9177948978 Mashhad, Iran.
authors.forename: Alireza
authors.initials: A
authors.lastname: Vakili
authors.affiliation: †Department of Animal Science, Ferdowsi University of Mashhad, 9177948978 Mashhad, Iran.
authors.forename: Mohsen Danesh
authors.initials: MD
authors.lastname: Mesgaran
authors.affiliation: §Wageningen UR Livestock Research, De Elst 1, 6708 WD Wageningen, The Netherlands.
authors.forename: Gert
authors.initials: G
authors.lastname: van Duinkerken
authors.affiliation: #College of Animal Science and Veterinary Medicine, Tianjin Agricultural University, Tianjin 300384, China.|⊥Department of Animal and Poultry Science, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5A8, Canada.
authors.forename: Peiqiang
authors.initials: P
authors.lastname: Yu
mesh_terms: D000821:Animal Feed / Q000032:analysis; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D001426:Bacterial Proteins / Q000096:biosynthesis / Q000378:metabolism*; D002417:Cattle; D003612:Dairying; D004044:Dietary Proteins / Q000378:metabolism*; D004063:Digestion; D002523:Edible Grain; D007408:Intestinal Absorption; D008954:Models, Biological; D012417:Rumen / Q000378:metabolism* / Q000382:microbiology*; D013213:Starch / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D004044:Dietary Proteins; D013213:Starch
keywords: DVE/OEB system; NRC-2001 model; concentrates; dairy cows; protein evaluation