ORIGINAL PAPER
The effect of protected lysine and methionine on milk yield and its composition in lactating dairy cows fed grass silage-based rations
 
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1
Department of Human Nutrition, The Agricultural University of Cracow, Al. 29 Listopada 46, 31-425 Kraków, Poland
2
Department of Animal Nutrition, The Agricultural University of Cracow, Al. 29 Listopada 46, 31-425 Kraków, Poland
Publication date: 1999-07-05
 
J. Anim. Feed Sci. 1999;8(3):341–353
 
KEYWORDS
ABSTRACT
Five multiparous Polish Red-and-White cows, weeks 8-12 of lactation, in a 5 x 5 Latin square treatment were fed a total mixed ration with grass silage and concentrates (58 and 42% DM). The five treatments were dietary supplements of protected L-lysine and DL-methionine (Smartamine™ ML) and DL-methionine (Smartamine™M) fed in the following amounts: I : 0 g/d + 0 g/d; II: 35 g/d + 0 g/d; III: 35 g/d + 10 g/d; IV: 35 g/d + 20 g/d; and V: 35 g/d + 30 g/d. The corresponding intestinal concentrations of lysine and methionine (% PDI) were: I: 6.89 and 1.88; II: 7.37 and 2.05; III: 7.32 and 2.29; IV: 7.31 and 2.54; V: 7.28 and 2.78, respectively. The D MI and milk yield were similar among treatments. In contrast, milk protein content was significantly increased (P<0.05) over the II treatment and then varied little. Milk fat content and yield varied inconsistently. Plasma metabolites such as glucose and (3-hydroxybutyrate were not affected and fell within physiological limits. Plasma free amino acids responded to the treatments, particularly lysine (PO.05) and methionine (P<0.001), producing a pattern of responses similar to that described for milk protein. Significant increases in milk protein content in the second treatment (Smartamine™ ML, 35 g/d) as resulting from improved postruminal supply of lysine (equal to needs), confirm the validity of the assumed requirement for this amino acid (i.e. 7.3% PDI). These increases could have also been due to a higher supply of limiting methionine. However, further improvements in intestinal supply of methionine, gradually meeting the assumed requirement (i.e. 2.5% PDI), had no effect on milk protein content. This lack of responses to methionine (treatments III-V), could have resulted either from a higher postruminal supply of this amino acid than that predicted or from a lower methionine requirement than that assumed.
 
CITATIONS (4):
1.
Effect of rumen-protected methionine on feed intake, milk production, true milk protein concentration, and true milk protein yield, and the factors that influence these effects: A meta-analysis
R.A. Patton
Journal of Dairy Science
 
2.
Impacts of manipulating ration metabolizable lysine and methionine levels on the performance of lactating dairy cows: A systematic review of the literature
P.H. Robinson
Livestock Science
 
3.
Meta-analysis of lactation performance in dairy cows receiving supplemental dietary methionine sources or postruminal infusion of methionine
G.I. Zanton, G.R. Bowman, M. Vázquez-Añón, L.M. Rode
Journal of Dairy Science
 
4.
Effects of Dietary Supplements of Folic Acid and Rumen-Protected Methionine on Lactational Performance and Folate Metabolism of Dairy Cows
C.L. Girard, H. Lapierre, J.J. Matte, G.E. Lobley
Journal of Dairy Science
 
ISSN:1230-1388