| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
University of Nebraska,2, Lincoln 68583
Abstract
Two steer trials and one lamb trial were conducted to evaluate dried delactosed whey (DDW) as a source of rumen-degradable protein and its effect on microbial protein synthesis. In steer trial 1, four abomasally-cannulated yearling Hereford-Angus steers (275 kg) were randomly allotted in a 4 x 4 Latin square with a 2 x 2 factorial arrangement of treatments. All steers were fed 5.91 kg of feed dry matter daily. Supplementation of a 63% ensiled corncob-30% solka floc diet with .15 kg DDW/head daily tended to increase flow to the abomasum of nonammonia N (NAN), bacterial N and total amino acids compared with supplementation with urea only. Compared with supplementation with urea alone, supplementation of a 63% ensiled corncob-30% corn starch diet with DDW tended to increase amino acid flow, but did not affect bacterial N flow. In steer trial 2, six abomasally-cannulated yearling Hereford-Angus steers (310 kg) were randomly allotted in a 6 x 6 Latin square with a 2 x 3 factorial arrangement of treatments. All steers were fed restricted levels of feed based on ad libitum consumption of the urea control diet. Supplementation of the urea control diet with DDW tended to increase NAN flow, bacterial N flow (P<.09) and total amino acid flow (P<.06) to the abomasum. Supplementation of a soybean meal (SBM) diet with DDW did not affect NAN flow, bacterial N flow or total amino acid flow. Supplementation of a blood meal (BM)-urea diet with DDW tended to increase total amino acid flow, but did not affect NAN flow or bacterial N flow. Nonammonia N and total amino acid flows were greatest on diets supplemented with 38% BM >95% SBM >100% urea as proportions of supplemental N. In trial 3, six ruminally-cannulated Rambouillet-Suffolk lambs (33 kg) were randomly allotted in a 6 x 6 Latin square with a 2 x 3 factorial arrangement of treatments. All lambs were fed restricted levels of feed based on ad libitum consumption of the urea control diet. Supplementation of the urea control diet with DDW increased (P<.05) diaminopimelic acid as a percentage of ruminal organic matter, and increased the molar proportions of iso-butyrate (P<.05) and isovalerate (P<.05) in ruminal fluid. It was concluded that when urea supplied all the supplemental N in low protein-high roughage diets, DDW increased microbial protein synthesis. Supplementation of SBM or BM-urea diets with DDW did not increase microbial protein synthesis.
1 Published as Paper No. 7843, Journal Series, Nebraska Agr. Exp. Sta.
3 Dept. of Anim. Sci., Kansas State Univ., Manhattan 66506.
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
