Journal article

Mapping quantitative trait loci (QTL) in sheep. IV. Analysis of lactation persistency and extended lactation traits in sheep

Elisabeth Jonas, Peter C Thomson, Evelyn JS Hall, David McGill, Mary K Lam, Herman W Raadsma



BACKGROUND: In sheep dairy production, total lactation performance, and length of lactation of lactation are of economic significance. A more persistent lactation has been associated with improved udder health. An extended lactation is defined by a longer period of milkability. This study is the first investigation to examine the presence of quantitative trait loci (QTL) for extended lactation and lactation persistency in sheep. METHODS: An (Awassi × Merino) × Merino single-sire backcross family with 172 ewes was used to map QTL for lactation persistency and extended lactation traits on a framework map of 189 loci across all autosomes. The Wood model was fitted to data from multiple lactatio..

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University of Melbourne Researchers


Funding Acknowledgements

The authors are particularly grateful to Dr Matthew Hobbs for his work on the QTL assembly and uploading the QTL onto the ovine genome browser. A special thanks also to Mrs Marilyn Jones and Mrs Gina Attard for their assistance in the genome scan, Mr Dave Palmer, Mr Joe Davis, Ms Renee Deever and the many casual staff who have contributed to the rearing of the lambs, the husbandry of the sheep, and the collation of data. The research was approved by the University of Sydney Animal Ethics Committee. The authors are grateful to the former CRC for Innovative Dairy Products, Australia for partial funding of this project. The resource flock and part of the sheep dairy was established with contributions from Mr Tom Grant and Mr Phillip Grant from Awassi Australia and a grant from the Australian Research Council.