Ruminal availabilities of protein and starch: effects on growth and ruminal and plasma metabolites of dairy calves.
Newborn Holstein calves (n = 75) were blocked by date of birth and sex and assigned randomly to one of eight isonitrogenous starters that contained protein and starch sources of different ruminal availabilities. Soybean meal or soybeans roasted to an exit temperature of 146 degrees C, raw or conglomerated corn, and urea at 1% of DM or no urea were used in a 2 x 2 x 2 factorial arrangement. The conglomeration process consisted of grinding the grain, adding water, pelleting the mixture, and roasting, which increased the degree of starch gelatinization fivefold. Starters were fed for ad libitum intake from 0.5 to 8 wk. Urea supplementation of conglomerated corn starters depressed performance, but the depression was greater when conglomerated corn was used with soybean meal than when it was used with roasted soybeans. Ruminal NH3 and plasma urea increased with increased RDP in starters, but the response varied according to corn type and soy protein source. Urea supplementation depressed plasma Lys, doubled plasma Cit with soybean meal and conglomerated corn starters, but depressed plasma Cit with roasted soybeans and conglomerated corn starters. Conglomerated corn depressed plasma Val and Gly, and roasted soybeans increased plasma Phe. Performance was similar when calves consumed starters containing ruminally synchronous or asynchronous CP and starch sources.
Abdelgadir
I E
IE
Department of Animal Sciences and Industry, Kansas State University, Manhattan 66506, USA.
Morrill
J L
JL
Higgins
J J
JJ
D000596:Amino Acids / Q000097:blood; D000641:Ammonia / Q000378:metabolism; D000821:Animal Feed; D000818:Animals; D000831:Animals, Newborn / Q000254:growth & development* / Q000378:metabolism; D001786:Blood Glucose / Q000378:metabolism; D002417:Cattle / Q000254:growth & development* / Q000378:metabolism; D002951:Citrates / Q000097:blood; D019343:Citric Acid; D004040:Dietary Carbohydrates / Q000378:metabolism*; D004044:Dietary Proteins / Q000378:metabolism*; D004435:Eating; D005232:Fatty Acids, Volatile / Q000378:metabolism; D005260:Female; D008297:Male; D012417:Rumen / Q000378:metabolism*; D013025:Glycine max; D013213:Starch / Q000378:metabolism*; D014508:Urea / Q000008:administration & dosage / Q000097:blood; D015430:Weight Gain; D003313:Zea mays
D000596:Amino Acids; D001786:Blood Glucose; D002951:Citrates; D004040:Dietary Carbohydrates; D004044:Dietary Proteins; D005232:Fatty Acids, Volatile; D019343:Citric Acid; D000641:Ammonia; D014508:Urea; D013213:Starch