Reducing the Effects of Heat Stress and Ageing on Sperm DNA damage in Thoroughbred Stallions

The University of Newcastle

  • Project code: PRO-015570

  • Project stage: Current

  • Project start date: Sunday, July 31, 2022

  • Project completion date: Monday, September 29, 2025

  • National Priority: HOR-Thoroughbred horse welfare, workforce safety and environmental sustainability


Ageing and heat stress in Thoroughbred stallions is associated with compromised offspring performance, a decline in fertility, and decreased libido, all of which contribute to substantial economic losses for the industry. Following 11 years of collaborative research between the University of Newcastle and the Hunter Valley Equine Research Centre, we have shown that around 15% of stallions have age-related subfertility and that a further 20% are susceptible to heat stress, a phenomenon that was revealed during AgriFutures Project PRJ-011268. The downstream result of these stressors is damage to the sperm DNA, resulting in lower pregnancy rates due to early embryo death and late-term abortion, or poor offspring health and performance. This AgriFutures Project will facilitate the assemblage of prominent expert scientists and industry stakeholders to work collaboratively to benefit Australian Thoroughbred breeders by developing strategies to reduce the economic and welfare implications associated with declining reproductive performance in these stallion cohorts.
The overarching benefits of this study will be two-fold: by addressing causes of sperm DNA damage, we will improve the fertility of heat stress susceptible stallions, and prolong the breeding life of aged, but genetically valuable stallions. This will be achieved through both an advanced diagnostic route, identifying DNA damage and oxidative stress, and targeted management interventions that reduce oxidative stress and improve sperm DNA integrity. This will lead to improved breeding efficiency, reducing the number of covers required to achieve a pregnancy and reducing the incidence of pregnancy loss and poor offspring performance associated with paternal DNA damage.



Thoroughbred Horses

Research Organisation

The University of Newcastle