Abstract #M21
Section: ADSA Production PhD Poster Competition (Graduate)
Session: ADSA Production PhD Poster Competition (Graduate)
Format: Poster
Day/Time: Monday 7:30 AM–9:30 AM
Location: Exhibit Hall A
Session: ADSA Production PhD Poster Competition (Graduate)
Format: Poster
Day/Time: Monday 7:30 AM–9:30 AM
Location: Exhibit Hall A
# M21
Nitrogen metabolism in lactating dairy cows supplemented with N-acetyl-l -methionine as a source of rumen-protected methionine.
F. X. Amaro*1, E. J. C. Duvalsaint1, D. Kim1, R. Restelatto1, P. Carvalho1, A. Oyebade1, Y. Jiang1, A. P. Cervantes1, K. G. Arriola1, L. F. Ferraretto1, A. T. Adesogan1, J.-S. Eun2, J. S. Park2, S. H. Lee2, D. Vyas1, 1Department of Animal Sciences, University of Florida, Gainesville, FL, 2Institute of Integrated Technology, CJ CheilJedang, Suwon, South Korea.
Key Words: dairy cow, N-acetyl-l -methionine (NALM), nitrogen metabolism
Nitrogen metabolism in lactating dairy cows supplemented with N-acetyl-
F. X. Amaro*1, E. J. C. Duvalsaint1, D. Kim1, R. Restelatto1, P. Carvalho1, A. Oyebade1, Y. Jiang1, A. P. Cervantes1, K. G. Arriola1, L. F. Ferraretto1, A. T. Adesogan1, J.-S. Eun2, J. S. Park2, S. H. Lee2, D. Vyas1, 1Department of Animal Sciences, University of Florida, Gainesville, FL, 2Institute of Integrated Technology, CJ CheilJedang, Suwon, South Korea.
The objective was to determine if supplementing a methionine (Met) derivative, N-acetyl-l -Met (NALM; CJ CheilJedang, Seoul, South Korea) would affect nitrogen (N) metabolism and improve N efficiency in lactating dairy cows. Sixty multiparous Holstein dairy cows in early lactation (27 ± 4.3 DIM) were assigned to 4 treatments in a randomized complete block design. Cows were blocked by actual milk yield and calving date. Treatments were: (1) Control (no NALM); (2) 15 g/d NALM (15NALM); (3) 30 g/d NALM (30NALM); and (4) 45 g/d NALM (45NALM). The NALM product contained 78% Met with 99.5% purity and based on bioavailability values provided from manufacturer, adding 15, 30, and 45 g/d as top-dress onto corresponding experimental diets provided 8, 16, and 24 g/d of metabolizable Met, respectively. Diets were formulated to meet nutritional requirements of lactating dairy cows producing 42 kg/d and to under supply metabolizable Met (−8 g/d; Control) or provide adequate (15NALM), or excess (+8 g/d with 30 NALM; +16 g/d with 45 NALM) metabolizable Met. Samples (feces, urine, blood, rumen fluid, and milk) were collected during the covariate period (2 wk), and at wk 4, 8, 16, and 24 of the treatment period. Data were analyzed using GLIMMIX procedure of SAS using covariates for N intake, fecal-N, urine-N, blood urea nitrogen (BUN), milk urea nitrogen (MUN), ammonia-N (NH3-N) and N efficiency. Contrast statements were included to test linear and quadratic effects of NALM along with Control versus all NALM treatments. Intake of N (P = 0.40) and N loss in feces (P = 0.79), and urine (P = 0.50) and ruminal NH3-N concentration (P = 0.57) were not affected by NALM supplementation, compared with Control. The efficiency of N utilization, measured as conversion of intake N into milk protein, was quadratically (P = 0.03) improved with NALM. No effect was observed on MUN concentration; however, BUN levels were linearly (P < 0.01) and quadratically (P < 0.01) reduced with NALM supplementation. In summary, NALM supplementation improved efficiency of N utilization and decreased BUN concentration.
Key Words: dairy cow, N-acetyl-
