DOCTORANDI SHINE!

Collaboration between the Western Cape Department of Agriculture and Stellenbosch University leads to two PhDs.

by Prof. Schalk Cloete

TTwo doctorandi completed their studies in the joint research programme of the Western Cape Department of Agriculture and Stellenbosch University at the AgriSciences graduation ceremony on 4 April 2022. Both newly promoted doctorandi were recently appointed as research scientists at the Directorate Animal Sciences of the Western Cape Department of Agriculture, where they will continue with their research. Their studies are briefly introduced here.

Cornelius Loftus (Nelius) Nel

Studies on genetic responses and genomic characterisation in South African and Australian sheep

The study conducted by Nelius demonstrated that direct selection for lambs weaned per ewe mated in the Elsenburg Merino flock induced substantial direct gains, also benefitting its components – fertility, twinning and rearing ability.

Selection impaired staple strength among the wool traits. Lamb survival benefited from selection, particularly under cold stress. Genomic analyses comparing common breeds across South Africa and Australia demonstrated that common breeds were closely related, thus benefitting future across-country evaluation. Genomic information added value to the evaluation of live weight, wool and reproduction traits in five institutional Merino resource flocks at Elsenburg, Grootfontein, Cradock, Tygerhoek and Langgewens as well as five selected commercial Merino flocks participating in sheep recording and managed by four prominent breeders. The study paved the way for further genomic studies on local sheep. as well as temperament were repeatable and/or heritable, allowing current flock and future generation gains. Selection under an assisted reproduction regime could enhance performance and the bird-human interface, thereby promoting ethical and sustainable ostrich farming.

Nelius’s study was conducted in collaboration with Drs Gretha Snyman and Willem Olivier, colleagues at the Grootfontein Agricultural Development Institute, as well as the Animal Genetics and Breeding Unit (AGBU) and the University of New England (UNE) at Armidale, Australia. Part of his study was indeed undertaken at AGBU and UNE under the supervision of respectively Dr Andrew Swan and Prof Julius van der Werf. He was supervised by Profs Schalk Cloete and Kennedy Dzama at Stellenbosch University and Dr Andrew Swan at AGBU.

Unfortunately, the COVID-19 pandemic prevented him from returning to Australia for additional joint studies with the team members situated there. This did not deter him and he was able to publish three papers in accredited international journals, namely the Journal of Thermal Biology (impact factor – 2.90), Animal Production Science (impact factor – 1.53) and BMC Genomics (impact factor – 3.97). He also had a four-page paper in the accredited, peer-reviewed Proceedings of the Association for the Advancement of Animal Breeding and Genetics (ISSN number – 1328-3227) and contributed two abstracts, one each to the Book of Abstracts of the SA Society for Animal Science Congress in 2019 and the Virtual Proceedings of the 6th International Conference for Quantitative Genetics in 2020.

Recently his paper submitted at the World Congress on Genetics Applied to Livestock Production (WCGALP) was also accepted as an oral communication at the 12th WCGALP meeting in Rotterdam during July 2022.

Three external examiners from South Africa, Australia and New Zealand were unanimous in their commendation of Nelius’s study for the volume and scientific depth it demonstrated.

The point of departure for Tonny’s study was that assisted reproduction and positive humanostrich interactions may improve fertility and docility.

Several external collaborators contributed to Tonny’s study. His study on seasonal influences was conducted in collaboration with Dr Lizette du Plessis and Prof John Soley, colleagues at the University of Pretoria (UP). He was supervised by Dr Maud Bonato and Prof Schalk Cloete at Stellenbosch University and Dr Irek Malecki of the University of Western Australia (UWA) in Perth.

He published two papers in accredited international journals, namely Tropical Animal Health and Production (impact factor – 1.56) and the Journal of Applied Poultry Research (impact factor – 1.15). Two further papers were accepted by the journals Animals (impact factor – 2.75) and Theriogenology (impact factor – 2.74). He also contributed three abstracts, one each to the 2019 and 2021 Books of Abstracts of the South African Society for Animal Science Congress, as well as to the Virtual Workshop of the World’s Poultry Congress (WPC) in 2021. Recently his abstract for the proceedings of the WPC meeting in Paris during August 2022 was also accepted.

Female Fertility And Reproduction Traits

Firstly, he established the seasonality of male and female reproductive traits, adapted sperm doses and insemination frequencies to maintain fertility in females, and demonstrated the hatching of live chicks after insemination. A female flock producing eggs without males was also established. The notoriously cantankerous temperament of ostriches was improved by habituating day-old chicks to humans during the post-hatching period. Key male and

Three external examiners, two from South Africa and one from Australia, praised Tonny’s study for the novelty, volume and scientific depth it demonstrated. Further studies on the artificial insemination of ostriches were recommended. AP

For more information, contact Prof Schalk Cloete