The effect of jugular or abomasal infusion of amino acids on milk yield in lactating cows fed a protein deficient diet.
The influence of first-pass splanchnic metabolism was investigated by comparing the response of 5 lactating cows to an infusion of an amino acid mixture into the abomasum or a jugular vein over 5 d according to a complete block design. The basal diet and the amino acid infusion provided 71% and 14% of crude protein requirements, respectively. The jugular infusion increased (P = 0.01) milk yield by 0.80 kg in comparison to the abomasal infusion, but milk protein yield was not altered. The jugular infusion tended to increase (P = 0.06) the arterial concentration of total essential amino acids by 11% relatively to the abomasal infusion. Mammary plasma flow and net fluxes of amino acids and glucose were not affected by the infusion sites. Variations in essential amino acid concentrations suggest that splanchnic metabolism alters peripheral delivery of amino acids but the recirculation of amino acids within the animal decreased the impact of the first-pass splanchnic metabolism on lactational performances.
Thivierge
M Carole
MC
Département des Sciences Animales, Université Laval, Sainte-Foy, QC, Canada.
Bernier
Jean F
JF
Dubreuil
Pascal
P
Lapierre
Hélène
H
D000018:Abomasum; D000596:Amino Acids / Q000008:administration & dosage*; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D002417:Cattle / Q000502:physiology*; D004044:Dietary Proteins / Q000008:administration & dosage; D019587:Dietary Supplements; D005260:Female; D007262:Infusions, Intravenous / Q000662:veterinary; D007267:Injections; D007774:Lactation / Q000378:metabolism*; D008892:Milk / Q000378:metabolism*; D008894:Milk Proteins / Q000032:analysis / Q000378:metabolism*; D011488:Protein Deficiency
D000596:Amino Acids; D004044:Dietary Proteins; D008894:Milk Proteins