Premium
Steer Intake, Digestion, and Ingestive Behavior of Switchgrass and Alfalfa Hays
Author(s) -
Burns J. C.,
Fisher D. S.
Publication year - 2013
Publication title -
crop science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.76
H-Index - 147
eISSN - 1435-0653
pISSN - 0011-183X
DOI - 10.2135/cropsci2012.07.0458
Subject(s) - dry matter , panicum virgatum , zoology , hay , neutral detergent fiber , biology , perennial plant , ruminant , digestion (alchemy) , chemistry , agronomy , bioenergy , microbiology and biotechnology , pasture , biofuel , chromatography
Perennial, warm‐season grasses cut for hay frequently have inadequate crude protein (CP) concentrations for acceptable ruminant performance. This study determined the influence of alfalfa ( Medicago sativa L.) as a CP supplement to steers ( Bos taurus ) fed switchgrass ( Panicum virgatum L.) hay harvested at the early‐heading stage. Diets of 100% switchgrass (SG) and 100% alfalfa (AL) were included along with 25, 50, and 75% mixtures of the hays making five treatments. Steer dry matter intake (DMI), whole tract dry matter digestibility (DMD), eating behavior, and masticate characteristics were estimated. Steer DMI averaged 1.35 kg 100 kg −1 body weight (BW) for 100% SG and increased linearly ( P < 0.01) to 2.93 kg 100 kg −1 BW for 100% AL. Also, DMD increased linearly ( P < 0.01) from 484 g kg −1 for 100% SG to 653 g kg −1 for 100% AL. Concentration of CP was 51 g kg −1 for SG and increased quadratically ( P < 0.01) to 241 g kg −1 with increasing AL while neutral detergent fiber (NDF) decreased quadratically ( P < 0.01) from 792 g kg −1 for SG to 407 g kg −1 for AL. Masticate in vitro dry matter disappearance (IVDMD) increased quadratically ( P < 0.01) from 509 g kg −1 for SG to 660 g kg −1 in AL whereas CP increased linearly ( P < 0.01) from 60 g kg −1 for SG to 230 g kg −1 in AL. Increasing AL of the as‐fed hay linearly decreased ( P < 0.01) chews per gram of dry matter, IVDMD, and CP but increased quadratically ( P < 0.01) chews per gram of NDF. Steers readily ate the SG:AL combinations; AL could thus provide a source of CP for SG based diets.