Abstract #T400
Section: Ruminant Nutrition
Session: Ruminant Nutrition: Dairy II
Format: Poster
Day/Time: Tuesday 7:30 AM–9:30 AM
Location: Gatlin Ballroom
Session: Ruminant Nutrition: Dairy II
Format: Poster
Day/Time: Tuesday 7:30 AM–9:30 AM
Location: Gatlin Ballroom
# T400
Effect of dietary energy source and protein supply on mammary amino acid metabolism of dairy cows.
Helio Rezende Lima Neto1, Helene Lapierre2, Lorraine Doepel*1, 1University of Calgary, Calgary, AB, Canada, 2Agriculture and Agri-Food Canada, Sherbrooke, QC, Canada.
Key Words: metabolizable protein, energy source, amino acid
Effect of dietary energy source and protein supply on mammary amino acid metabolism of dairy cows.
Helio Rezende Lima Neto1, Helene Lapierre2, Lorraine Doepel*1, 1University of Calgary, Calgary, AB, Canada, 2Agriculture and Agri-Food Canada, Sherbrooke, QC, Canada.
The objective of this study was to determine the interaction of dietary energy source and metabolizable protein (MP) supply on AA arterial concentration and mammary arterial-venous difference (AVdiff). Eight Holstein cows were used in a double 4 × 4 Latin square design with 21-d periods. Energy source and MP supply were tested in a factorial arrangement with the following dietary treatments: high fiber, high protein (HFHP); high fiber, low protein (HFLP); high starch, high protein (HSHP); and high starch, low protein (HSLP). Diets were formulated to supply 100% of the NEL requirement, and 100% (HP) or 70% (LP) of MP requirement. Arterial concentrations of Ile, Leu, Phe, and the branched-chain AA (BCAA) were higher with HF compared with HS, regardless of MP supply, whereas concentrations of His, Leu, and BCAA were higher, or tended to be higher, with HP compared with LP. Group 1 AA-N (His, Met, Trp, Phe+Tyr) concentration tended to be higher with HP than LP but Group 2 AA-N (Ile, Leu, Ly, Val) concentration was not different between HP and LP. Metabolizable protein supply did not affect AVdiff except for Ile, Leu and BCAA, in which it was greater for HP than LP (P < 0.10). Energy source did not affect AVdiff. The concentration of total essential AA-N (TEAAN) was higher with HF and HP relative to HS and LP, but AVdiff was not affected by treatment. Protein supply had a greater influence on AVdiff than did energy source, whereas energy source and MP supply influenced essential AA concentrations. Dietary energy source and MP affected several production variables; those data are presented in a companion abstract.
Table 1.
| Arterial concentration, μm | Treatments | SEM | P-value | ||||
| HFHP | HFLP | HSHP | HSLP | HF vs. HS | HP vs. LP | ||
| G1AAN | 327.9 | 287.4 | 306.9 | 291.9 | 19.24 | 0.56 | 0.07 |
| G2AAN | 540.8 | 481.5 | 448.4 | 432.4 | 24.89 | <0.01 | 0.12 |
| BCAA | 438.5 | 366.0 | 349.6 | 329.0 | 19.78 | <0.01 | 0.02 |
| TEAAN | 881.3 | 799.5 | 792.7 | 748.3 | 40.19 | 0.06 | 0.09 |
| Ile | 91.4 | 92.0 | 75.8 | 75.9 | 4.95 | <0.01 | 0.94 |
| Lys | 51.2 | 57.7 | 49.3 | 51.9 | 3.06 | 0.16 | 0.11 |
| Met | 22.9 | 21.9 | 22.8 | 21.1 | 1.07 | 0.62 | 0.13 |
| Phe | 59.2 | 51.6 | 47.2 | 49.7 | 3.08 | 0.02 | 0.36 |
Key Words: metabolizable protein, energy source, amino acid
