Fiber and nitrogen fractions of forages and by-product feeds determined by in vitro and in situ procedures

Objectives were to determine dry matter, fiber and nitrogen fractions, and in vitro and in situ degradability of forages and by-product feeds, and to compare in vitro methods of estimating rumen degradability with the in situ bag technique. Feeds analyzed with number of samples in parentheses included alfalfa as baled hay (23), alfalfa ensiled in conventional (43), and. oxygen limiting silos (39), ammonia· treated (25), and untreated corn silage from conventional (17) and bunker silos (17), rye (25), sorghum (7), wheat (6), barley (5), and orchardgrass (4) silages, orchardgrass (19) and fescue hay (3), and dried distillers grains dark colored (2) and light (1), wet brewers grains (1), and whole cottonseeds (3). Samples were analyzed for dry matter, crude protein, buffer-soluble protein, protease insoluble nitrogen, neutral and acid detergent fiber and insoluble nitrogen, and in situ degradability of nitrogen, dry matter, and fiber. Protease insoluble nitrogen, buffer-insoluble protein, and neutral detergent insoluble nitrogen were lowest for alfalfa from conventional upright silos. Oxygen limiting silo samples had greater dry matter, insoluble protein, and bound nitrogen compared to conventional upright silo samples. Oxygen limiting silos had 35.9% of samples with bound nitrogen greater than 15% of total nitrogen compared to 14% of conventional upright silo samples. Baled hay and oxygen limiting silo samples had similar protease insoluble nitrogen, however, ensiled samples had greater bound nitrogen. In situ nitrogen degradability was greatest for ensiled forages compared to hays. Ensiled forages had the greatest A fraction (rapidly solubilized), alfalfa hay the greatest B fraction (slowly degraded), and orchardgrass hay the greatest C fraction (not degraded). Degradation of dry matter and fiber followed similar patterns for each forage and by-product. Significant results were found by comparing in vitro and in situ techniques for estimating degradability. Due to differences between hay and silage, use of one technique can not be recommended at this time to predict degradability. For silage, the best measure related to in situ degradability was buffer-soluble protein; for hay, the best measure was neutral detergent insoluble nitrogen.

Name thesis:degree_name

Ph. D.

Level thesis:degree_level

doctoral

Discipline thesis:degree_discipline

Animal Science

Department dc:contributor.department

Animal Science

Grantor dc:publisher

Virginia Polytechnic Institute and State University

Year dc:date.issued

1986

Author dc:creator

• Janicki, Francis John

Chair dc:contributor.committeechair

• Stallings, Charles

Committee members dc:contributor.committeemember

• Polan, Carl E.
• Jones, Gerald M.
• McGilliard, Michael L.
• Webb, Kenneth E. Jr.
• Vinson, William E.

Statement dc:rights

• In Copyright

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Handle dc:identifier.uri

http://hdl.handle.net/10919/49798

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/49798