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Co-variance component estimation for South African Hereford, Charolais, and Angus cattle for application in genetic evaluations
Dissertation (MSc Agric (Animal Science))--University of Pretoria, 2024.
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University of Pretoria
2025
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| _version_ | 1867613649363795968 |
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| access_status_str | Open Access |
| author2 | Van Marle-Koster, Este |
| author_browse | Van Marle-Koster, Este |
| author_facet | Van Marle-Koster, Este |
| collection | Thesis |
| dc_rights_str_mv | © 2023 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 (Animal Science))--University of Pretoria, 2024. |
| format | Thesis |
| id | oai:repository.up.ac.za:2263/100823 |
| institution | University of Pretoria (South Africa) |
| language | English |
| last_indexed | 2026-06-10T12:39:30.213Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UPSpace — University of Pretoria Institutional Repository |
| publishDate | 2025 |
| publishDateRange | 2025 |
| publishDateSort | 2025 |
| 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:2263/100823 Co-variance component estimation for South African Hereford, Charolais, and Angus cattle for application in genetic evaluations Van Marle-Koster, Este hannahkruger1@gmail.com Theron, Helena Kruger, Hannah UCTD Sustainable Development Goals (SDGs) Genetic parameters Heritability estimates Multi-trait animal model Genetic trends Genetic correlations Animal model Dissertation (MSc Agric (Animal Science))--University of Pretoria, 2024. This study developed (co)variance components and heritability estimates for growth traits in South African Angus, Charolais, and Hereford cattle, well-established breeds farmed locally for over a century. Genetic parameters are required for genetic evaluations. In this study genetic parameters were estimated for the specific populations by using single- and multi-trait models based on available data over 10-year (2012-2022) and 20-year (2002-2022) periods. Key traits analysed included birth weight, weaning weight, yearling weight, and 18-month weight, Average Daily Gain (ADG), hip height, body length and scrotal circumference. This study developed single and multi-trait models for (co)variance estimations. The single-trait models for Angus birth weight exhibited higher direct heritability estimates (0.41 to 0.49) compared to weaning weight (0.02 to 0.26), yearling weight (0.05 to 0.43), and 18-month weight (0.25 to 0.44) for the Angus breed. The Charolais exhibited similar results, and the Hereford estimates varied across the traits with large variability, birth weight (0.001 – 0.29), weaning weight (0.03 – 0.19), yearling weight (0.07 – 0.25) and 18-month weights (0.01 – 0.56). Single-trait models indicate the role of environmental effects such as inclusion of Sire by Herd (SXH) effects in breed models which raises residual variance, and the Permanent Environment (PE) effect which impacted traits from birth to 18 months, therefore they must be evaluated for inclusion. For Angus, multi-trait heritability estimates were (0.50 ± 0.02, 0.43 ± 0.02) for birth weight, (0.31 ± 0.24, 0.27 ± 0.02) for weaning weight, (0.50 ± 0.04, 0.36 ± 0.03) for yearling weight, and (0.35 ± 0.06, 0.39 ± 0.03) for 18-month weight in the 2012-2022 and 2002-2022 datasets, respectively. Charolais estimates showed birth weight heritability estimates of (0.36 ± 0.04, 0.42 ± 0.03), weaning weight at (0.19 ± 0.03, 0.20 ± 0.03), yearling weight at (0.07 ± 0.02, 0.13 ± 0.03) and 18-month weight at (0.10 ± 0.04, 0.17 ± 0.04) for the same periods. For Hereford (2012-2022 data only), heritability for birth weight was 0.32 ± 0.03, weaning weight 0.20 ± 0.03, yearling weight 0.32 ± 0.06, and 18-month weight 0.46 ± 0.08. Post-wean growth test traits heritability estimates were estimated on the larger data set of 2002-2022. Angus demonstrated moderate to high heritability for ADG (0.19 ± 0.05) and scrotal circumference (0.37 ± 0.07). Charolais exhibited moderate heritability for average daily gain (0.39 ± 0.30) and scrotal circumference (0.57 ± 0.28), and Hereford cattle showed moderate heritability for average daily gain (0.31 ± 0.10) but lower estimates for scrotal circumference (0.21 ± 0.10). The study emphasizes dataset limitations and recommends complete recording and genomic-based parentage testing to improve the accuracy of variance components and estimated breeding values for breeders. UP Postgraduate Masters Research Bursary Animal and Wildlife Sciences Msc Agric (Animal science) Unrestricted Faculty of Natural and Agricultural Sciences SDG-15: Life on land 2025-02-13T09:40:03Z 2025-02-13T09:40:03Z 2025-04 2024-10 Dissertation * A2025 http://hdl.handle.net/2263/100823 https://doi.org/10.25403/UPresearchdata.28400948 en © 2023 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 | UCTD Sustainable Development Goals (SDGs) Genetic parameters Heritability estimates Multi-trait animal model Genetic trends Genetic correlations Animal model Co-variance component estimation for South African Hereford, Charolais, and Angus cattle for application in genetic evaluations |
| title | Co-variance component estimation for South African Hereford, Charolais, and Angus cattle for application in genetic evaluations |
| title_full | Co-variance component estimation for South African Hereford, Charolais, and Angus cattle for application in genetic evaluations |
| title_fullStr | Co-variance component estimation for South African Hereford, Charolais, and Angus cattle for application in genetic evaluations |
| title_full_unstemmed | Co-variance component estimation for South African Hereford, Charolais, and Angus cattle for application in genetic evaluations |
| title_short | Co-variance component estimation for South African Hereford, Charolais, and Angus cattle for application in genetic evaluations |
| title_sort | co variance component estimation for south african hereford charolais and angus cattle for application in genetic evaluations |
| topic | UCTD Sustainable Development Goals (SDGs) Genetic parameters Heritability estimates Multi-trait animal model Genetic trends Genetic correlations Animal model |
| url | http://hdl.handle.net/2263/100823 https://doi.org/10.25403/UPresearchdata.28400948 |