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Free amino acid supplementation to steers: effects on ruminal fermentation and performance.
- Source :
-
Journal of animal science [J Anim Sci] 1997 Apr; Vol. 75 (4), pp. 1167-78. - Publication Year :
- 1997
-
Abstract
- Three studies were conducted to evaluate amino acid utilization by cattle. In Exp. 1, five steers (580 kg) were fed 86% rolled corn diets with mixtures of amino acids containing up to 6 g/d DL-Met, 24 g/d L-Lys, 6 g/d L-Thr, and 3 g/d L-Trp. Treatments had little effect on ruminal fermentation, diet digestibility, N flow to the duodenum, or microbial efficiency. Ruminal concentrations of Met and Lys increased linearly (P < .05) with amino acid supplementation, whereas Thr responded quadratically, and Trp was not altered. In Exp. 2, four steers (414 kg) were used to measure effects of dietary monensin or laidlomycin propionate in high-grain diets supplemented with amino acids. Ionophores had no significant effect on ruminal fermentation or outflows of amino acids from the rumen. In Exp. 3, 100 steers (287 kg initial BW) were fed diets containing 1% of a nonprotein N source. Treatments were 1) no supplemental N (UREA), 2) UREA plus soybean meal (SBM), 3) UREA plus 2 g/d DL-Met, 8 g/d L-Lys, 2 g/d L-Thr, and 1 g/d L-Trp, or 4) UREA plus 4 g/d DL-Met, 16 g/d L-Lys, 4 g/d L-Thr, and 2 g/d L-Trp. During the growing period (diets based on whole-plant milo silage), gains were higher for SBM-supplemented steers than for UREA steers and intermediate for steers supplemented with amino acids. Few significant differences in performance were observed among treatments during the finishing phase (diets based on dry-rolled corn) or for the entire experiment, but cattle fed SBM or amino acids tended to be fatter and have better marbling scores and quality grades. Amino acids did not greatly alter ruminal fermentation or cattle performance.
- Subjects :
- Amino Acids administration & dosage
Amino Acids metabolism
Animal Nutritional Physiological Phenomena
Animals
Body Composition drug effects
Body Composition physiology
Cattle physiology
Diet standards
Diet veterinary
Digestion drug effects
Digestion physiology
Edible Grain standards
Fermentation drug effects
Fermentation physiology
Food, Fortified
Ionophores pharmacology
Lysine administration & dosage
Lysine metabolism
Lysine pharmacology
Male
Methionine administration & dosage
Methionine metabolism
Methionine pharmacology
Nitrogen metabolism
Rumen drug effects
Rumen metabolism
Threonine administration & dosage
Threonine metabolism
Threonine pharmacology
Tryptophan administration & dosage
Tryptophan metabolism
Tryptophan pharmacology
Urea administration & dosage
Urea metabolism
Urea pharmacology
Amino Acids pharmacology
Cattle growth & development
Cattle metabolism
Rumen physiology
Subjects
Details
- Language :
- English
- ISSN :
- 0021-8812
- Volume :
- 75
- Issue :
- 4
- Database :
- MEDLINE
- Journal :
- Journal of animal science
- Publication Type :
- Academic Journal
- Accession number :
- 9110233
- Full Text :
- https://doi.org/10.2527/1997.7541167x