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Effects of fat coated rumen bypass lysine and methionine on performance of dairy cows fed a diet deficient in lysine and methionine
Author(s) -
WATANABE Kazumasa,
FREDEEN Alan H.,
ROBINSON Peter H.,
CHALUPA William,
JULIEN William E.,
SATO Hiroyuki,
SUZUKI Hiroyuki,
KATOH Kazuo,
OBARA Yoshiaki
Publication year - 2006
Publication title -
animal science journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.606
H-Index - 38
eISSN - 1740-0929
pISSN - 1344-3941
DOI - 10.1111/j.1740-0929.2006.00377.x
Subject(s) - methionine , rumen , dry matter , lactation , lysine , neutral detergent fiber , zoology , dairy cattle , chemistry , food science , feces , excretion , biology , amino acid , biochemistry , fermentation , pregnancy , paleontology , genetics
Two experiments were conducted to evaluate the effect of fat coated rumen bypass lysine (RPLys) and methionine (RPMet) on the lactation performance of dairy cows. In Experiment 1, three lactating cows were supplied with RPLys and fat coated DL‐Met which was highly protected (H‐RPMet) as an indigestible marker, and total fecal emission was collected for 72 h following administration. Measuring the proportional difference in fecal excretion of lysine derived from RPLys relative to methionine derived from H‐RPMet, the intestinal availability of RPLys was estimated to be 66.2%. In Experiment 2, 20 multiparous Holstein cows producing approximately 40 kg/day of milk were assigned to two treatments; fed RPLys (16 g/day as lysine) and RPMet (6.5 g/day as methionine) or none (control) from 5 to 21 weeks postpartum. The consumption of dry matter, organic matter, crude protein, neutral detergent fiber and acid detergent fiber were significantly more in the control cows throughout the experimental period. Their milk protein yield, the contents of their milk protein and milk fat were higher by 0.03 kg ( P = 0.03), 0.06% ( P < 0.001) and 0.11% ( P = 0.07), respectively, in the treatment group compared to the control. These results suggest that the RPLys and RPMet used in this study improved the lactation performance of dairy cows.