title: Performance and meat quality traits of beef heifers fed with two levels of concentrate and ruminally undegradable protein.
abstract: The effects of two levels of concentrate and ruminally undegradable protein (RUP) on performance, intake, digestibility, carcass characteristics, meat quality traits, and commercial cuts yield were assessed. Twenty crossbred heifers (240 kg average body weight) were used. At the beginning of the trial, four animals were slaughtered as reference group and the 16 remaining animals were randomly assigned to four treatments, in a 2 × 2 factorial design: two levels of concentrate (40% and 80%, dry matter (DM) basis) and two levels of RUP (48.79% and 27.19% of CP). At the end of the trial, all the animals were slaughtered. There was no interaction (P > 0.05) between concentrate and RUP levels. Dry matter intake and nutrients digestibility was not affected (P > 0.05) by RUP level. Heifers fed the highest RUP level had greater (P < 0.05) average daily gain (ADG). Concentrate level did not affect (P > 0.05) DMI and ADG. Heifers fed diets with 80% concentrate had greater intake of TDN and EE, and lower intake of NDF (P < 0.05). The digestibilities of all nutrients, except the NDF, were greater (P < 0.05) for the 80% concentrate diets. The RUP levels did not affect (P > 0.05) the carcass characteristics and carcass gain composition. Heifers fed 80% concentrate diets had larger (P < 0.05) longissimus muscle area and lower gain of bones (P < 0.05). Concentrate level did not affect (P > 0.05) the composition of carcass gain. There was no effect (P > 0.05) of RUP and concentrate levels on meat quality traits and commercial cut yields.
authors.affiliation: Departamento de Zootecnia da Universidade Federal de Viçosa, Viçosa, MG, 36570-000, Brazil. marcio_dsouza@hotmail.com
authors.forename: Marcio de Souza
authors.initials: Mde S
authors.lastname: Duarte
authors.forename: Pedro Veiga Rodrigues
authors.initials: PV
authors.lastname: Paulino
authors.forename: Sebastião de Campos
authors.initials: Sde C
authors.lastname: Valadares Filho
authors.forename: Mario Fonseca
authors.initials: MF
authors.lastname: Paulino
authors.forename: Edenio
authors.initials: E
authors.lastname: Detmann
authors.forename: Joanis Tilemahos
authors.initials: JT
authors.lastname: Zervoudakis
authors.forename: João Paulo Ismerio dos Santos
authors.initials: JP
authors.lastname: Monnerat
authors.forename: Gabriel da Silva
authors.initials: Gda S
authors.lastname: Viana
authors.forename: Luiz Henrique P
authors.initials: LH
authors.lastname: Silva
authors.forename: Nicola Vergara Lopes
authors.initials: NV
authors.lastname: Serão
mesh_terms: D000821:Animal Feed; D000822:Animal Husbandry; D000818:Animals; D002417:Cattle / Q000254:growth & development / Q000502:physiology*; D004032:Diet; D004044:Dietary Proteins / Q000378:metabolism; D004063:Digestion; D002149:Energy Intake; D004734:Energy Metabolism; D008460:Meat; D011897:Random Allocation; D012417:Rumen / Q000378:metabolism*; D015430:Weight Gain
chemical_list: D004044:Dietary Proteins