title: Flint corn grain processing and citrus pulp level in finishing diets for feedlot cattle.
abstract: Four trials were conducted to evaluate the effects of flint corn processing and the replacement of corn with citrus pulp (CiP) in diets for Nellore feedlot cattle. In a 103-d finishing trial, 216 Nellore bulls (350 ± 24 kg initial BW) were used in a randomized complete block design with a 2 × 4 factorial arrangement of treatments. Factors included 2 processing methods, either ground corn (GC) or steam-flaked corn (FC), with CiP replacing each corn type at 4 levels (0, 25, 50, and 75% of DM). All diets contained 12% sugarcane bagasse and 88% concentrate (DM basis). Treatments were also evaluated in metabolism trials, in which 10 ruminally cannulated Nellore steers (389 ± 37 kg) were assigned to 2 independent but simultaneous 5 × 5 Latin squares, each using 1 method of corn processing (GC and FC). Interactions ( < 0.05) between corn processing and CiP inclusion level were observed for final BW, DMI, ADG, G:F, and HCW. With FC-based diets, added CiP linearly decreased final BW ( = 0.04), whereas with GC-based diets, added CiP quadratically increased final BW ( = 0.002). With FC-based diets, the inclusion of CiP linearly increased DMI ( = 0.03) and linearly decreased ADG ( = 0.03) and G:F ( = 0.001). Increasing CiP in GC-based diets quadratically increased DMI ( = 0.001), ADG ( = 0.005), and HCW ( = 0.003). In FC-based diets, CiP inclusion had no effect on HCW ( = 0.21). Dressing percent, LM area, and 12th-rib fat were not affected by diet ( ≥ 0.05). For steers fed GC diets, CiP inclusion in the diet quadratically decreased the molar proportion of isovalerate ( = 0.001) but linearly increased ruminal butyrate ( = 0.006). No differences ( ≥ 0.16) were observed for total VFA concentrations, acetate:propionate ratio, and ruminal NH-N as CiP replaced GC. For steers fed FC diets, the molar proportion of acetate linearly increased ( = 0.002) whereas the proportion of propionate was linearly decreased ( < 0.001), resulting in a linear increase ( = 0.001) in the acetate:propionate ratio. Replacing corn with CiP linearly reduced NEm ( = 0.001) and NEg ( < 0.001) of FC-based diets but did not affect ( = 0.15) NE values of CG-based diets. Steam flaking flint corn improved cattle performance in this trial more than has been reported for dent corn in the published literature.
authors.forename: V N
authors.initials: VN
authors.lastname: Gouvêa
authors.forename: F
authors.initials: F
authors.lastname: Batistel
authors.forename: J
authors.initials: J
authors.lastname: Souza
authors.forename: L J
authors.initials: LJ
authors.lastname: Chagas
authors.forename: C
authors.initials: C
authors.lastname: Sitta
authors.forename: P R B
authors.initials: PR
authors.lastname: Campanili
authors.forename: D B
authors.initials: DB
authors.lastname: Galvani
authors.forename: A V
authors.initials: AV
authors.lastname: Pires
authors.forename: F N
authors.initials: FN
authors.lastname: Owens
authors.forename: F A P
authors.initials: FA
authors.lastname: Santos
mesh_terms: D000821:Animal Feed / Q000032:analysis*; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D002417:Cattle / Q000378:metabolism*; D002482:Cellulose / Q000737:chemistry; D002957:Citrus / Q000737:chemistry*; D004032:Diet / Q000662:veterinary*; D005511:Food Handling / Q000379:methods*; D008297:Male; D008903:Minerals / Q000378:metabolism; D013227:Steam; D003313:Zea mays / Q000737:chemistry* / Q000378:metabolism
chemical_list: D008903:Minerals; D013227:Steam; D002482:Cellulose; C027433:bagasse