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The effect of vitreousness on starch disappearance rate and monetary value of yellow and white maize
Thesis (MScAgric)--Stellenbosch University, 2026.
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| Format: | Thesis |
| Language: | English |
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Stellenbosch : Stellenbosch University
2026
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| _version_ | 1867613892911300608 |
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| access_status_str | Open Access |
| author | Pollard, Naulette |
| author2 | Van Zyl, J. H. C. |
| author_browse | Pollard, Naulette Van Zyl, J. H. C. |
| author_facet | Van Zyl, J. H. C. Pollard, Naulette |
| author_sort | Pollard, Naulette |
| collection | Thesis |
| dc_rights_str_mv | Stellenbosch University |
| description | Thesis (MScAgric)--Stellenbosch University, 2026. |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/135932 |
| institution | Stellenbosch University (South Africa) |
| language | English |
| last_indexed | 2026-06-10T12:43:21.794Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository |
| publishDate | 2026 |
| publishDateRange | 2026 |
| publishDateSort | 2026 |
| publisher | Stellenbosch : Stellenbosch University |
| publisherStr | Stellenbosch : Stellenbosch University |
| record_format | dspace |
| source_str | SUNScholar — Stellenbosch University Repository |
| spelling | oai:scholar.sun.ac.za:10019.1/135932 The effect of vitreousness on starch disappearance rate and monetary value of yellow and white maize Pollard, Naulette Van Zyl, J. H. C. Cruywagen, C. W. Stellenbosch University. Faculty of AgriSciences. Dept. of Animal Science. Thesis (MScAgric)--Stellenbosch University, 2026. Pollard, N. 2026. The effect of vitreousness on starch disappearance rate and monetary value of yellow and white maize. Unpublished masters thesis. Stellenbosch: Stellenbosch University [online]. Available: https://scholar.sun.ac.za/items/5b14a1a0-6f9d-4328-8b04-297713f637b7 Maize (Zea mays L.) is the primary source of dietary starch in ruminant feed systems and plays an important role in production performance efficiency in intensive dairy operations. Although maize kernel vitreousness have been recognised as an important quality trait influencing ruminal starch degradation, its economic implications for animal production have not been sufficiently determined. This thesis investigated the effect of maize vitreousness on starch disappearance rate and evaluated the use of fermentation kinetics to estimate animal performance and the monetary value of maize for ruminant production systems, specifically dairy operations. Two studies were conducted. In the first study, yellow and white maize samples were evaluated to determine the relationship between kernel vitreousness and ruminal starch degradation kinetics. Maize hardness was quantified using the near-infrared spectroscopy technique, and starch disappearance rate (kd) was estimated using in vitro gas production techniques. The results demonstrated a strong inverse relationship between kernel vitreousness and starch degradation rate, confirming that increased vitreousness reduced starch degradation rate. Differences between maize colour and vitreousness interactions further highlighted the variability in fermentation characteristics among maize types. The second study applied the starch degradation rate values (kd) determined in the previous research within the Agricultural Modeling and Training Systems (AMTS) model to estimate animal production performance and evaluate the economic implications. By incorporating kd values into formulation modelling, predicted milk yield responses, feed efficiency, and maize breakeven prices were calculated. The findings indicated that maize with the lowest vitreousness and the highest starch degradation rates resulted in improved predicted production performance and greater economic value. Conversely, maize with higher vitreousness exhibited reduced ruminal starch utilisation, leading to lower predicted production outcomes and reduced economic returns. Overall, the results demonstrated that maize quality cannot be adequately evaluated based on chemical composition alone and that degradation kinetics play a major role in determining both animal performance and economic value. By including starch degradation rate into production modelling provided a practical framework for converting maize quality differences into financial outcomes. This study demonstrated the potential for developing a maize quality index for ruminants that incorporates vitreousness-related degradation characteristics, allowing more informed on-farm feed purchasing decisions and improve profitability, especially under volatile feed price conditions. Masters 2026-04-15T12:21:24Z 2026-04-15T12:21:24Z 2026-03 Thesis https://scholar.sun.ac.za/handle/10019.1/135932 en Stellenbosch University 87 pages application/pdf Stellenbosch : Stellenbosch University |
| spellingShingle | Pollard, Naulette The effect of vitreousness on starch disappearance rate and monetary value of yellow and white maize |
| title | The effect of vitreousness on starch disappearance rate and monetary value of yellow and white maize |
| title_full | The effect of vitreousness on starch disappearance rate and monetary value of yellow and white maize |
| title_fullStr | The effect of vitreousness on starch disappearance rate and monetary value of yellow and white maize |
| title_full_unstemmed | The effect of vitreousness on starch disappearance rate and monetary value of yellow and white maize |
| title_short | The effect of vitreousness on starch disappearance rate and monetary value of yellow and white maize |
| title_sort | effect of vitreousness on starch disappearance rate and monetary value of yellow and white maize |
| url | https://scholar.sun.ac.za/handle/10019.1/135932 |
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