Project snapshot: Reducing the effects of heat stress and ageing on sperm DNA in Thoroughbred stallions
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THOROUGHBRED HORSES
Project snapshot: Understanding a Recessive Embryo-Lethal Genotype in Australian Thoroughbred Horses
6 pages
Published: 7 May 2026
Author(s): Gibb, Z.
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Early pregnancy loss is a growing problem for the Australian Thoroughbred breeding industry. This AgriFutures project looks at a common inherited gene linked to these losses.
Around half of all Thoroughbreds carry one copy of this gene. No horses have been found with two copies, which suggests affected embryos fail very early, before a pregnancy can be detected. Researchers are working with major breeding regions across Australia. They will collect hair samples from 500–1,000 stallions and broodmares to see how common the gene is across bloodlines and locations.
The research will help explain pregnancy losses that currently have no clear cause. It will also give breeders clearer information about the risks linked to certain matings. Over time, this work may support a future genetic test. This would help breeders plan matings with more confidence.
By reducing repeat covers, vet costs and handling, the project aims to improve breeding efficiency, horse welfare and the long‑term future of the Australian Thoroughbred industry.
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