Phosphorus excretion in beef steers as impacted by increasing levels of corn gluten feed

Overfeeding of phosphorus (P) is a contributing factor to P levels in surface waters. The objective of this study was to determine the impact of increasing levels of corn gluten feed (CGF) as a supplemental source of P on fecal P excretions. Eight Hereford steers (427±79 kg) were randomly assigned to one of four dietary treatments in a 4 x 4 replicated Latin square design. Steers were fed chopped grass hay ad libitum (0.13% P) and 0, 0.5, 1.0 or 1.5 kg/d of dried CGF pellets. All steers were supplemented with 0.91 kg/d beet pulp, 0.34 kg/d rumen-inert fat supplement and 18.14 g/d trace mineral salt. Urea was added to the respective diets at levels of 95.25, 72.57, 49.90, and 31.75 g/d to ensure equal dietary protein across treatments. Steers were housed individually and fitted with total fecal collection bags. Steers were adjusted to each diet for 9-d followed by a 5-d collection period. Following the final collection of each period, a 10 ml jugular blood sample was collected and analyzed to determine serum inorganic P. Dietary total P increased (P < 0.05) as CGF level increased: 8.72, 12.59, 16.75 and 20.88 g/d. Dry matter digestibility increased linearly (P < 0.05) as dietary P increased: 50.35, 53.66, 54.25 and 55.42%. Total P excretion increased linearly (P < 0.05) with increasing CGF level: 9.66, 11.71, 14.29, 16.96 g/day. Inorganic P excretion increased linearly (P < 0.05) with increasing CGF level: 4.11, 5.93, 8.36 and 9.92 g/day. Total P excretion was highly related (P < 0.05; r2 = 0.79) to inorganic P excretion. Serum inorganic P increased linearly (P < 0.05) with increasing dietary P content: 5.61, 5.87, 6.64 and 6.80 mg/dL. Fecal P increased as CGF level increased in steers fed varying dietary levels of P from plant sources. Management of P intake can be a strategic practice to reduce P fecal excretions in beef cattle.

Name thesis:degree_name

Master of Science

Level thesis:degree_level

masters

Discipline thesis:degree_discipline

Animal and Poultry Sciences

Department dc:contributor.department

Animal and Poultry Sciences

Grantor dc:publisher

Virginia Tech

Year dc:date.issued

2014

Author dc:creator

• Harmon, Deidre Danielle

Chair dc:contributor.committeechair

• McCann, Mark A.

Committee members dc:contributor.committeemember

• El-Kadi, Samer Wassim
• Hanigan, Mark D.

• Beef Cattle
• Phosphorus
• Fecal Excretions

Statement dc:rights

• In Copyright

Licence dc:rights.uri

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

Dc Identifier Other

vt_gsexam:3690

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/50510