Time of daily supplementation for steers grazing dormant intermediate wheatgrass pasture

• Published in: Journal of animal science Vol. 70; no. 2; p. 547
• Main Authors: Barton, R.K. (Eastern Oregon Agricultural Research Center, Burns), Krysl, L.J, Judkins, M.B, Holcombe, D.W, Broesder, J.T, Gunter, S.A, Beam, S.W
• Format: Journal Article
• Language: English
• Published: United States 01.02.1992
• Subjects: ACIDE GRAS VOLATIL; ACIDO GRASO VOLATIL; ADDITIF; ADITIVOS; Animal Feed; Animals; Blood Glucose - analysis; Blood Urea Nitrogen; BOEUF; BUEY; Cattle - blood; Cattle - physiology; COMPORTEMENT ALIMENTAIRE; Cottonseed Oil - administration & dosage; Dietary Proteins - administration & dosage; DIGESTIBILIDAD; DIGESTIBILITE; DIGESTION; Eating; ELYMUS; Fatty Acids, Nonesterified - blood; Feeding Behavior; FERMENTACION; FERMENTATION; Food, Fortified; Gastrointestinal Transit; GRAINE DE COTON; HABITOS ALIMENTARIOS; Hormones - blood; INGESTION DE PIENSO; Kinetics; Male; METABOLITE; METABOLITOS; PASTOREO; PATURAGE; PESO; Poaceae; POIDS; PRISE ALIMENTAIRE (ANIMAUX); PROTEINAS; PROTEINE; RUMEN; Rumen - metabolism; SEMILLA DE ALGODON; SERUM SANGUIN; SUERO SANGUINEO; TEMPS; TIEMPO; Time Factors; TORTAS OLEAGINOSAS; TOURTEAU D'OLEAGINEUX
• ISSN: 0021-8812; 1525-3163
• DOI: 10.2527/1992.702547x

To compare the effects of time of daily protein supplementation on grazing behavior, forage intake, digesta kinetics, ruminal fermentation, and serum hormones and metabolites, 12 ruminally cannulated Holstein steers (449 and 378 kg average initial and final BW, respectively) were allotted to three groups. Treatments consisted of CON = no supplement, AM = cottonseed meal (.25% of BW) at 0600, and PM = cottonseed meal (.25% of BW) at 1200. Steers grazed a dormant (1.1% N) intermediate wheatgrass (Thinopyrum intermedium Host) pasture. Sampling trials occurred in December, January, and February. Supplementation altered (P = 0.01) time spent grazing; CON steers grazed approximately 1.5 h longer than supplemented steers. Supplemented steers lost less (P = 0.02) BW (-40 kg) than CON steers (-75 kg) did. Supplementation did not alter (P 0.15) forage OM intake; however, total OM intake was greater (P = 0.01) for supplemented steers (22.3 g/kg of BW) than for CON (18.4 g/kg of BW steers. Supplementation did not affect (P 0.15) digesta kinetics. Extent of in situ NDF (96 h) and rate (%/h) of disappearance for supplemented steers was greater (P = 0.01) than for CON steers. Across all periods, ruminal NH3 N and total VFA concentrations were lower (P = 0.01) for CON steers than for supplemented steers. Serum insulin (ng/mL) concentration was lower (P = 0.03) and concentration of serum growth hormone (ng/mL) was higher (P = 0.02) for CON steers than for supplemented steers. Cottonseed meal supplementation enhanced utilization of intermediate wheatgrass; however, supplementation time had minimal effects on the variables measured