Effects of source of supplemental nutrients on forage intake, digestive kinetics and protein supply to the small intestine of grazing calves /
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| Other Authors: | , , |
| Format: | Thesis Book |
| Language: | English |
| Published: |
1991.
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| Subjects: | |
| Online Access: | ProQuest, Abstract Link to OAKTrust copy |
| Abstract: | The major aim of this research was to determine effects of source of supplemental nutrients on forage intake, kinetics of digestion and protein flow to the small intestine of calves grazing either common bermudagrass or annual ryegrass. Three markers of microbial protein (MM) and methods for utilizing them in partitioning feed from microbial protein were also compared. Trial one evaluated the effects of supplements containing primarily corn and urea (EN), solvent cottonseed meal (CSM), feather meal (FE) or Menhaden fish meal (FI) fed to calves grazing bermudagrass. Trial two evaluated the effects of supplements containing primarily minerals only (MIN), corn (CORN), solvent cottonseed meal (CSM), blood meal (BL), feather meal (FE), Menhaden fish meal (FI) or a commercial condensed molasses product containing cottonseed meal (PDQ) all fed to calves grazing ryegrass. Treatments FE and CSM depressed forage intake and FI and BL (on ryegrass only) stimulated forage intake. True protein from BL, FE and FI appeared to have the greatest potential to escape ruminal degradation. The fraction of protein escaping ruminal degradation was less for all supplements for animals grazing ryegrass because of a faster turnover of ryegrass vs bermudagrass. Forage residues had slower turnovers than supplemental residues for both pasture trials. Digestibility appeared increased slightly with supplementation of corn or high protein supplements (except CSM). Comparison of trichloroacetic acid insoluble (TCAI) [^32]P, TCAI [^35]S and diaminopimelic acid (DAPA) suggested that either TCAI [^35]S or DAPA were appropriate MM provided that duodenal contents were used to determine the ratio of MM to microbial protein rather than ruminal contents. The fraction of intake protein escaping ruminal degradation was essentially equal whether estimated from ruminal rates of protein degradation (determined in two in situ trials) coupled with the in vivo residue turnover or estimated in vivo. Correction for microbial attachment to residues after in situ incubation appeared necessary to accurately estimate ruminal degradation of feed proteins. Residues uncorrected for microbial attachment consistently yielded a slower rate of ruminal protein degradation. Collectively, these data imply that composition of feed amino acids escaping to the duodenum have nutritional consequences in regulating forage intake. |
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| Item Description: | Typescript (photocopy). Vita. "Major subject: Nutrition." |
| Physical Description: | xii, 170 leaves : illustrations ; 29 cm |
| Bibliography: | Includes bibliographical references. |