Abstract #T278

# T278
Assessing potentially digestible NDF and energy content of canola meal from twelve Canadian crushing plants over four production years.
E. M. Paula*1, J. L. P. Daniel2, H. H. A. Costa3, A. Faciola1, 1University of Nevada, Reno, NV, 2Universidade Estadual de Maringa, Maringa, PR, Brazil, 3Universidade Estadual Vale do Acarau, Sobral, Ceara, Brazil.

The objective of this study was to assess NDF digestibility and energy content of canola meals (CM) produced in Canada over a 4-year period. Canola meal samples were collected from 12 Canadian crushing plants over 4 years (total = 48) and analyzed for chemical composition, potentially digestible NDF (pdNDF), total digestible nutrients at maintenance (TDN1x), and NEL simulating a cow consuming 3× maintenance (NEL3x). To estimate TDN1x and NEL3x, pdNDF was calculated as: (1) pdNDFOBS = (NDF − NDICP − iNDF), using observed CM iNDF values after 288-h in situ ruminal incubations; (2) pdNDFNRC = (NDF − NDICP − ADL) × {1 − [ADL/(NDF − NDICP)]0.667}, according to NRC 2001; (3) pdNDFCNCPS = (NDF − NDICP − iNDF), according to the CNCPS that calculates iNDF as acid detergent lignin (ADL) × 2.4. Concentrations of NDF, NDICP, and ADL in all equations were given in % of DM. Truly digestible NDF was estimated multiplying the observed and predicted pdNDF by 0.75. Then TDN1x and NEL3x were calculated assuming a diet with 74% of TDN1x according to NRC 2001 equations. Regressions of predicted (NRC or CNCPS) vs. observed values were performed using Proc Reg of SAS (Table 1). pdNDFOBS, pdNDFNRC, and pdNDFCNCPS averaged 15, 8, and 2.4% of DM, respectively. The TDN1x average were 73, 67, and 64%, respectively. The NEL3x average were 1.88, 1.73, and 1.63 Mcal/kg, and ranged from 1.73 to 2.08; 1.51 to 1.94; and 1.4 to 1.87 Mcal/kg DM for NEL3xOBS, NEL3xNRC, and NEL3xCNCPS, respectively. Our results indicate that NEL3x from CM diets may be underestimated in current nutritional models due to underestimations in CM NDF digestibility. More accurate information on CM NDF digestibility may improve energy content estimation, thus improving diet formulation accuracy. Table 1.

Key Words: acid detergent lignin, indigestible NDF, in situ