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Effects of diets differing in rumen soluble nitrogen on poor quality roughage utilization by sheep
Dissertation (MSc(Agric))--University of Pretoria, 2012.
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University of Pretoria
2013
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| _version_ | 1867613476179935232 |
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| access_status_str | Open Access |
| author2 | Van Niekerk, Willem A. |
| author_browse | Van Niekerk, Willem A. |
| author_facet | Van Niekerk, Willem A. |
| collection | Thesis |
| dc_rights_str_mv | © 2012, University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria |
| description | Dissertation (MSc(Agric))--University of Pretoria, 2012. |
| format | Thesis |
| id | oai:repository.up.ac.za:2263/29326 |
| institution | University of Pretoria (South Africa) |
| last_indexed | 2026-06-10T12:36:45.136Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UPSpace — University of Pretoria Institutional Repository |
| publishDate | 2013 |
| publishDateRange | 2013 |
| publishDateSort | 2013 |
| publisher | University of Pretoria |
| publisherStr | University of Pretoria |
| record_format | dspace |
| source_str | UPSpace — University of Pretoria Institutional Repository |
| spelling | oai:repository.up.ac.za:2263/29326 Effects of diets differing in rumen soluble nitrogen on poor quality roughage utilization by sheep Van Niekerk, Willem A. annarietmentz@gmail.com Jooste, Anna Margarietha Rumen soluble nitrogen Poor quality roughage Sheep Diets UCTD Dissertation (MSc(Agric))--University of Pretoria, 2012. The aim of this study was to determine whether a rapid release N source can be substituted with a slow release N source without having any negative effects on intake, digestibility, rumen fermentation and microbial protein synthesis, if sheep are fed a poor quality roughage. Five rumen cannulated wethers were used in the trial in a 5x5 latin square design. Cannulated wethers were assigned to different treatments after each experimental period. The treatments studied had different proportions of urea to OptigenrII, with the same inclusion level of starch and a mineral premix between treatments. The five different treatments were: 100% urea; 75% urea:25% OptigenrII; 50% urea:50% OptigenrII; 25% urea:75% OptigenrII and 100% OptigenrII. Significant differences (P<0.05) between the 25% urea:75% OptigenrII and the other treatments in terms of intake suggested that a combination of urea and OptigenrII might be the preferred supplementation due to a significantly higher dry matter intake (DMI), organic matter intake (OMI), neutral detergent fibre intake (NDF intake) and digestible organic matter intake (DOMI). The intake variables of 100% urea and 100% OptigenrII did not differ (p>0.05). No differences (P>0.05) were recorded for dry matter digestibility (DMD), organic matter digestibility (OMD) and neutral detergent fibre (NDF) digestibility between treatments. However, the 100% OptigenrII treatment had a significant (P<0.05) lower apparent nitrogen digestibility, which might be the result of a slower rumen NH3-N release and higher nitrogen excretion than the other treatments. No differences were observed for pH and VFA between different treatments. The rumen NH3-N concentration of the 100% OptigenrII treatment was significantly (P<0.05) lower than the 100% urea treatment at 2 and 4 hours after infusion. The effective degradability of both DM and NDF did not differ (P>0.05) between treatments. Neither were there differences between treatments for total microbial crude nitrogen (MCN) production. Based on biological evaluation, it could be suggested that urea might be substituted with OptigenrII in supplements. From an economical point of view, urea might still be the preferred NPN source, as urea is cheaper than OptigenrII in terms of R/kg nitrogen. Copyright Animal and Wildlife Sciences unrestricted 2013-09-07T15:25:22Z 2012-11-12 2013-09-07T15:25:22Z 2012-09-07 2012-11-12 2012-11-08 Dissertation Jooste, AM 2012, Effects of diets differing in rumen soluble nitrogen on poor quality roughage utilization by sheep, MSc dissertation, University of Pretoria, Pretoria, viewed yymmdd < http://hdl.handle.net/2263/29326 > E12/9/96/gm http://hdl.handle.net/2263/29326 http://upetd.up.ac.za/thesis/available/etd-11082012-192718/ © 2012, University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria application/pdf University of Pretoria |
| spellingShingle | Rumen soluble nitrogen Poor quality roughage Sheep Diets UCTD Effects of diets differing in rumen soluble nitrogen on poor quality roughage utilization by sheep |
| title | Effects of diets differing in rumen soluble nitrogen on poor quality roughage utilization by sheep |
| title_full | Effects of diets differing in rumen soluble nitrogen on poor quality roughage utilization by sheep |
| title_fullStr | Effects of diets differing in rumen soluble nitrogen on poor quality roughage utilization by sheep |
| title_full_unstemmed | Effects of diets differing in rumen soluble nitrogen on poor quality roughage utilization by sheep |
| title_short | Effects of diets differing in rumen soluble nitrogen on poor quality roughage utilization by sheep |
| title_sort | effects of diets differing in rumen soluble nitrogen on poor quality roughage utilization by sheep |
| topic | Rumen soluble nitrogen Poor quality roughage Sheep Diets UCTD |
| url | http://hdl.handle.net/2263/29326 http://upetd.up.ac.za/thesis/available/etd-11082012-192718/ |