Full Text Available
Note: Clicking the button above will open the full text document at the original institutional repository in a new window.
Nitrogen use efficiency in South African commercial dairy farms
Thesis (MScAgric)--Stellenbosch University, 2025.
Saved in:
| Main Author: | |
|---|---|
| Other Authors: | |
| Format: | Thesis |
| Language: | English |
| Published: |
Stellenbosch : Stellenbosch University
2025
|
| Subjects: | |
| Tags: |
No Tags, Be the first to tag this record!
|
| _version_ | 1867614103012376576 |
|---|---|
| access_status_str | Open Access |
| author | Smit, Hendrik |
| author2 | Raffrenato, Emiliano |
| author_browse | Raffrenato, Emiliano Smit, Hendrik |
| author_facet | Raffrenato, Emiliano Smit, Hendrik |
| author_sort | Smit, Hendrik |
| collection | Thesis |
| dc_rights_str_mv | Stellenbosch University |
| description | Thesis (MScAgric)--Stellenbosch University, 2025. |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/132277 |
| institution | Stellenbosch University (South Africa) |
| language | English |
| last_indexed | 2026-06-10T12:46:42.610Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository |
| publishDate | 2025 |
| publishDateRange | 2025 |
| publishDateSort | 2025 |
| publisher | Stellenbosch : Stellenbosch University |
| publisherStr | Stellenbosch : Stellenbosch University |
| record_format | dspace |
| source_str | SUNScholar — Stellenbosch University Repository |
| spelling | oai:scholar.sun.ac.za:10019.1/132277 Nitrogen use efficiency in South African commercial dairy farms Smit, Hendrik Raffrenato, Emiliano Van Zyl, Brink Stellenbosch University. Faculty of AgriSciences. Dept. of Animal Science. Dairy farms -- South Africa Nitrogen in animal nutrition -- Feeding and feeds Nitrogen in the body -- Measurement Nitrogen in agriculture Milk yield Proteins in animal nutrition Nitrogen -- Environmental aspects UCTD Thesis (MScAgric)--Stellenbosch University, 2025. Smit, H. 2025. Nitrogen use efficiency in South African commercial dairy farms. Unpublished masters thesis. Stellenbosch: Stellenbosch University [online]. Available: https://scholar.sun.ac.za/items/e21a11a7-aecc-45c5-8efd-6af38e2825e9 ENGLISH ABSTRACT: In this thesis, a review was made of the current literature regarding dairy nitrogen use efficiency, as well as research measuring the cattle -, milk -, urinary -, and faecal nitrogen efficiency of South African dairy farms utilizing different feeding strategies. The review represents an overview of dairy nitrogen use efficiency in terms of measurement techniques, reasons for improvement, and factors affecting nitrogen use efficiency. Nitrogen use efficiency is measured by comparing the nitrogen output to the nitrogen input, and in dairy, this is typically measured with milk nitrogen efficiency, comparing the amount of nitrogen found in the milk and the amount of nitrogen found in the feed. It was found that using other ways to measure the nitrogen use efficiency might be beneficial, such as cattle nitrogen efficiency, which involves the nitrogen use efficiency of the of producing and non-producing animals. There are large incentives to improve nitrogen efficiency on dairy farms, as it was shown to have major impacts on the surrounding environments, as well as affect the profitability of the farm. Research suggests that to improve nitrogen efficiency use on dairy farms, changes have to be made to the diet of the animal, and that they should be in good health. As both these factors may differ between feeding strategies, a study was done measuring the Cattle Nitrogen Efficiency between farms using total mixed ration (TMR) and farms feeding with pasture. The cattle nitrogen efficiency model measures nitrogen use efficiency by measuring Replacement Nitrogen Efficiency, Lactation Nitrogen Efficiency, and Lifetime Nitrogen Efficiency. Replacement Nitrogen Efficiency measures the nitrogen use efficiency of calves and heifers, Lactation Nitrogen Efficiency measures the nitrogen use efficiency of producing cows, and lifetime nitrogen use efficiency represents the nitrogen use efficiency of both. The results found in this thesis suggest that no significant differences exist for both Lactation Nitrogen Efficiency and Lifetime Nitrogen Efficiency between feeding strategies, while it was found that the Replacement Nitrogen Efficiency was significantly higher (p < 0.05) for TMR farms. This indicated improved calf and heifer rearing practices for the TMR farms. A second study was conducted measuring the milk -, urinary -, and faecal nitrogen efficiency of the same farms. Any fed nitrogen not found in the milk, will be excreted through the urine and faeces, and thus the nitrogen use efficiency of urine and faeces was measured to explain any inefficiencies that might occur in milk nitrogen efficiency. The results showed that there were significant differences, with TMR farms having improved (p < 0.05) milk nitrogen efficiency compared to pasture farms, and pasture farms having higher (p < 0.05) values for both urine -, and faecal nitrogen efficiency. The results of the study would suggest that these significant differences are due to differences found in the amount of rumen degradable protein fed. AFRIKAANSE OPSOMMING: In hierdie tesis, was die huidige literatuur rakende die stikstof doeltreffendheid van melkdiere ondersoek, sowel as studies gedoen op die bees -, melk -, urinêre -, en fekale stikstof doeltreffendheid op Suid-Afrikaanse melkplase, wat verskillende voedings strategieë gebruik. Die hersiening verteenwoordig 'n samevatting van die literatuur rakende stikstof doeltreffendheid in melkdiere in terme van hoe dit gemeet word, redes om dit te verbeter, en faktore wat die stikstof doeltreffendheid beïnvloed. Stikstof doeltreffendheid word gemeet deur die stikstof uitset te vergelyk met die stikstof inset, en in melkdiere word dit tipies gemeet deur melk stikstof doeltreffendheid, wat die hoeveelheid stikstof in die melk vergelyk met die hoeveelheid stikstof in die voer. Daar bestaan wel ander maniere om dit te doen, byvoorbeeld “Cattle Nitrogen Efficiency” (CNE), wat die stikstof doeltreffendheid van produserende- en nie-produserende diere insluit. Daar is ‘n groot aansporing om stikstof doeltreffendheid op melkplase te verbeter, aangesien dit beide die omgewing en winsgewendheid van die plaas negatief kan affekteer. Navorsing stel voor dat om stikstof doeltreffendheid op melkplase te verbeter, moet daar veranderinge aan beide die dieet en gesondheid gemaak word. Aangesien hierdie faktore kan verkil tussen voedings strategieë, het ons 'n studie gedoen om die CNE te meet tussen plase wat totaal gemengde rantsoen gebruik en plase wat met weiding voer. Die CNE model meet stikstof doeltreffendheid deur Vervangings Stikstof doeltreffendheid, laktasie stikstof doeltreffendheid, en lewenslange stikstof doeltreffendheid te meet. Vervangings stikstof doeltreffendheid meet die stikstof doeltreffendheid van kalwers en verse, laktasie stikstof doeltreffendheid meet die stikstof doeltreffendheid van produserende koeie, en lewenslange stikstof doeltreffendheid verteenwoordig die stikstof doeltreffendheid van beide. Die resultate van hierdie studie dui aan dat daar geen beduidende verskille vir beide laktasie stikstof doeltreffendheid en lewenslange stikstof doeltreffendheid tussen voedings strategieë was nie, terwyl dit gevind is dat die vervangings stikstof doeltreffendheid beduidend hoër was (p < 0.05) vir totaal gemengde rantsoen plase teenoor weidings plase. Dit dui dan daarop dat totaal gemengde rantsoen plase moontlik beter kyk na hul kalwers en verse tenoor weidings plase. 'n Tweede studie was uitgevoer om die melk -, urinêre -, en fekale stikstof doeltreffendheid van dieselfde plase te meet. Enige voedings stikstof wat nie in die melk gevind word nie, sal deur die urine en mis uitgeskei word, en dus is die stikstof doeltreffendheid van urine en mis gemeet om enige verskille wat in melk stikstof doeltreffendheid mag voorkom, te verduidelik. Die resultate het getoon dat daar beduidende verskille was, met totaal gemengde rantsoen plase wat beduidend beter (p < 0.05) melk stikstof doeltreffendheid gehad het in vergelyking met weiding plase, en weiding plase wat hoër (p < 0.05) waardes vir beide urinêre- en fekale stikstof doeltreffendheid gehad het. Die resultate van die studie dui daarop dat hierdie beduidende verskille bestaan as gevolg van verskille in die hoeveelheid rumenafbreekbare proteïen wat gevoer word. Masters 2025-06-02T10:45:17Z 2025-06-02T10:45:17Z 2025-03 Thesis https://scholar.sun.ac.za/handle/10019.1/132277 en Stellenbosch University 70 pages application/pdf Stellenbosch : Stellenbosch University |
| spellingShingle | Dairy farms -- South Africa Nitrogen in animal nutrition -- Feeding and feeds Nitrogen in the body -- Measurement Nitrogen in agriculture Milk yield Proteins in animal nutrition Nitrogen -- Environmental aspects UCTD Smit, Hendrik Nitrogen use efficiency in South African commercial dairy farms |
| title | Nitrogen use efficiency in South African commercial dairy farms |
| title_full | Nitrogen use efficiency in South African commercial dairy farms |
| title_fullStr | Nitrogen use efficiency in South African commercial dairy farms |
| title_full_unstemmed | Nitrogen use efficiency in South African commercial dairy farms |
| title_short | Nitrogen use efficiency in South African commercial dairy farms |
| title_sort | nitrogen use efficiency in south african commercial dairy farms |
| topic | Dairy farms -- South Africa Nitrogen in animal nutrition -- Feeding and feeds Nitrogen in the body -- Measurement Nitrogen in agriculture Milk yield Proteins in animal nutrition Nitrogen -- Environmental aspects UCTD |
| url | https://scholar.sun.ac.za/handle/10019.1/132277 |
| work_keys_str_mv | AT smithendrik nitrogenuseefficiencyinsouthafricancommercialdairyfarms |