title: [The effect of postruminal supplementation of energy or energy and proteins on feed intake in the ruminant calf].
abstract: Forty-eight Friesian bull calves were weaned at 8 weeks of age. They were divided into four groups (T, L, LS1 and LS2) 4 weeks before weaning. All the animals were fed a concentrate diet ad libitum, containing 16 p. 100 of crude protein on a DM basis, and hay. The animals of groups L, LS1 and LS2 also received a limited amount (24 p. 100 of the ingested DM) of a liquid supplement of deproteinized whey fed alone (group L) or mixed with 25 (group LS1) or 50 p. 100 (group LS2) of soybean oil-meal. The voluntary intake of DM/kg live weight0.75 was increased before weaning by giving the three liquid supplements (table 1). That effect lasted until 10 weeks of age in groups LS1 and LS2. On the contrary, the DM intake/kg0.75 decreased from 10 to 14 weeks of age in group L. From 15 to 19 weeks, the DM intake/kg0.75 was the same in group L as in group T, but was lower in groups LS1 and LS2. The plasma glucose level was higher in groups LS1 and LS2 than in group T; it was noticeably higher in group L than in group T (table 1). The plasma urea level was always very low in group L; the urea level of groups LS1 and LS2 was lower at 10 weeks of age than that of group T, but was as high (group LS1) or higher (group LS2) at 16 weeks (table 1). It is concluded that the voluntary intake of young ruminant calves is limited by rumen volume until 3 months of age; the supply of lactose or lactose and protein through the rumen bypass allows an increase in intake. After that period, voluntary intake is rapidly regulated by metabolic mechanisms in relation to the degree of satisfaction of energy and protein requirements; glycemia does not play a role in this regulation. As in monogastric animals, the nitrogen/energy ratio has a determining effect on the control of voluntary intake.
mesh_terms: D000375:Aging; D000821:Animal Feed; D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D002417:Cattle / Q000502:physiology*; D004032:Diet; D004044:Dietary Proteins / Q000008:administration & dosage / Q000494:pharmacology*; D004435:Eating / Q000187:drug effects*; D002149:Energy Intake; D008297:Male; D012417:Rumen / Q000502:physiology*; D014508:Urea / Q000097:blood; D014886:Weaning
chemical_list: D001786:Blood Glucose; D004044:Dietary Proteins; D014508:Urea
vernacular_title: Effet d'un apport postruminal d'énergie ou d'énergie et de protéines sur la prise alimentaire chez le veau ruminant.