Effects of Dietary Protein Degradability and Casein or Amino Acid Infusions on Production and Plasma Amino Acids in Dairy Cows

• Published in: Journal of dairy science Vol. 73; no. 3; pp. 735 - 748
• Main Authors: Seymour, William M., Polan, Carl E., Herbein, Joseph H.
• Format: Journal Article
• Language: English
• Published: Savoy, IL Elsevier Inc 01.03.1990; Am Dairy Sci Assoc; American Dairy Science Association
• Subjects: abomasal infusion; Abomasum - metabolism; amino acids; Amino Acids - administration & dosage; Amino Acids - blood; Animal Feed; Animals; Biological and medical sciences; Body Weight; casein; Caseins - administration & dosage; Cattle - blood; Cattle - physiology; Dietary Proteins - metabolism; Digestion; Eating; Female; Food industries; Fundamental and applied biological sciences. Psychology; Lactation - physiology; Lysine - administration & dosage; Mammary Glands, Animal - metabolism; Methionine - administration & dosage; Milk and cheese industries. Ice creams; Nitrogen - metabolism; Rumen - metabolism; casein; abomasal infusion; amino acids; Plasma; Lactation; Nutrition; Ox; Cow; Proteins; Vertebrata; Mammalia; Casein; Aminoacid; Artiodactyla; Ungulata; Comparative study; Digestibility
• ISSN: 0022-0302; 1525-3198
• DOI: 10.3168/jds.S0022-0302(90)78727-9

Responses to daily abomasal infusions of 400g sodium caseinate, 400g hydrolyzed casein, or 11.3g L-methionine plus 30.1g L-lysine were compared in eight Holstein cows fed diets with estimated ruminal protein degradabilities of 70 and 60.5%. Basal diets contained corn silage and corn with either soybean meal or 66.7:33.3 soybean meal:corn gluten meal added. Infusion with Methionine plus lysine increased milk protein content when cows were fed either diet but increased milk fat content and yield only when the soybean meal diet was fed. Sodium caseinate increased milk and milk protein production and decreased milk fat percentage. Concentration of total essential amino acids, branched chain amino acids, and urea cycle amino acids were increased by the infusion of both casein sources. Methionine-lysine infusion increased plasma lysine and taurine, a metabolite of methionine, suggesting that absorbed methionine was extensively metabolized. Results demonstrate an impact of both ruminal degradability of dietary protein and form of infused protein on amino acid nutrition of lactaring dairy cows.