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|Title:||The Nutritive Value of Normal and Brown Midrib Sorghum X Sudangrass Genotypes: Ruminal Characteristics and Site and Extent of Nutrient and Phenolic Compound Digestion by Sheep and Holstein Steers and Heifers|
|Author(s):||Wedig, Cindy Louise|
|Doctoral Committee Chair(s):||Jaster, E.H.,|
|Department / Program:||Animal Science|
|Degree Granting Institution:||University of Illinois at Urbana-Champaign|
|Subject(s):||Agriculture, Animal Culture and Nutrition|
|Abstract:||Objectives were to determine the influence of cell wall composition on extent of fiber degradation of brown midrib and normal genotypes of sorghum x sudangrass hybrids, and to determine differences in concentrations of lignin phenolics, liquid and particulate turnover rates in the rumen, and digestion of cell wall polysaccharides between normal and brown midrib genotypes of sorhgum x sudangrass in ruminants.
Normal and brown midrib genotypes of Redlan x Greenleaf and Redlan x Piper varieties of sorghum x sudangrass were utilized as dietary treatments. Four ruminally cannulated Holstein steers and eight yearling Holstein heifers were assigned to treatments in 4 x 4 Latin squares. Heifers and steers received ensiled first cutting forages at early head stage of maturity. Four sheep with ruminal, duodenal, and ileal cannulae received second cutting hays from prehead state of maturity.
Brown midrib silages were lower in ADF and ADL than were corresponding normal genotypes. Hays showed no genotypic differences in cell wall composition. Higher amounts of arabinose, galactose and uronic acids were detected in brown midrib mutants of silages than in normal genoytpes. Vanillin was higher and p-coumaric acid lower in brown midrib genotypes compared with normal genotypes for hays and silages.
Redlan x Greenleaf brown midrib mutant had higher digestibilities of organic matter and cell wall fractions than did its normal counterpart in growing Holstein heifers. Disappearance of the alkali labile phenolic acid, p-coumaric acid, was greater for normal genotypes than for brown midrib mutants in both heifers and steers. Digestibilities of the hemicellulosic monosaccharides, arabinose, xylose, and uronic acids by heifers were higher for brown midrib genotypes than for normal genotypes.
Extent of 72 h DM, NDF, ADF, hemicellulose, cellulose, and ADL digestion in situ was significantly higher for brown midrib mutants than for normal genotypes of sorghum x sudangrass varieties. Hemicellulosic monosaccharides, xylose and uronic acids, were more digestible in brown midrib mutants than in normal genotypes.
Ruminal digestibilities of NDF, ADF, and cellulose in sheep were higher for the brown midrib mutants than for normal genotypes. A higher total tract digestibility of cellulose was also detected for brown midrib mutants compared with corresponding normal genotypes.
Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1988.
|Date Available in IDEALS:||2014-12-16|