Semina: Ciências Agrárias (Feb 2015)

Site and extent of amino acid digestion in dairy cattle fed with corn and its byproducts

  • Reginaldo Nassar Ferreira ,
  • Jane Maria Bertocco Ezequiel ,
  • Rosemary Laís Galati ,
  • Juliana Borsari Dourado Sancanari,
  • Sérgio do Nascimento Kronka ,
  • Cristine dos Santos Settimi Cysneiros

DOI
https://doi.org/10.5433/1679-0359.2015v36n1p421
Journal volume & issue
Vol. 36, no. 1
pp. 421 – 430

Abstract

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The study was conducted to evaluated the site and extent of dry matter (DM), crude protein (CP), methionine (Met), lysine (Lys), and threonine (Thr) digestion of corn and byproducts obtained from corn germ mixed with different amounts of extruded or non-extruded ether extract (EE) in dairy cattle. Treatments consisted in eight types of feed and two processing in a 4 × 2 factorial design. There were four feeds: corn grain cracked (Corn), corn germ meal with 1% EE (CG1), corn germ meal with 7% EE (CG7), and corn germ meal with 10% EE (CG10). The feeds were processed in one of two ways: extruded (Ex) and not extruded. In situ techniques were used to determine DM, CP, Met, Lys, and Thr partial and total tract digestion. A basic diet was compounded of corn germ meal, soybean meal and coastcross hay in a 70:30 roughage to concentrate ratio. There was no interaction (P>0.05) between feeds and processing method. Extrusion improved (P0.05) for corn and corn germ meal mixed with 7 and 10% EE, regardless of EE processing method. The CP total tract digestibility of corn germ meal with 1% nonextruded EE was 16.62% higher (P<0.05) than that of the extruded form. The best total CP digestibility was obtained for corn germ meal with 7% EE, independently of the processing method. The effects of EE processing method on partial and total digestibility differed between amino acid. Corn and corn byproduct extrusion may improve dry matter digestibility, but do not necessarily influence crude protein digestion. Ruminal and intestinal digestibility of Met, Lys, and Thr depends on both feed type and processing method. Therefore, amino acid availability should be considered individually.

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