Oral Presentation ESA-SRB-AOTA 2019

From lab to paddock: fertility enhancements for the equine breeding industry (#66)

Zamira Gibb 1 , Aleona Swegen 1 , Roisin A Griffin 1 , Stephanie Waugh 1 , Robert J Aitken 1
  1. University of Newcastle, CALLAGHAN, NSW, Australia

The Australian equine industry is dominated by the production of the Thoroughbred (in which assisted reproductive technologies; ART, are prohibited) and the Standardbred (almost exclusively produced via ART) racehorse. These contrary breeding strategies present diverse obstacles for fertility enhancement, particularly for stallions. In the Thoroughbred, in vivo fertility improvements have been implemented through the development of an on-farm diagnostic test to identify periods of stallion subfertility, and via nutritional interventions using carnitine and omega-3 fatty acids to reduce sperm oxidative stress and improve membrane fluidity respectively. Current industry-focussed research is underway to develop an early pregnancy test for the mare and to identify stallions which are at risk of subfertility induced by heat stress. This information allows breeders to strategically manage these animals in such a way that will reduce the need for excessive veterinary interventions and reduce the crucial foaling-to-pregnancy interval so that horses are born as close to the 1st of August (and are therefore more mature at age-related sales and races) as possible. In contrast, to improve breeding efficiency for the AI-centric Standardbred, we have developed a synthetic sperm storage medium which preserves fertility for up to two weeks without the need to chill or cryopreserve, thereby overcoming the deleterious effects of cold shock and cryoinjury which are associated with increased sperm DNA damage, reduced longevity following thawing or warming and ultimately, reduced fertility. The fertility of spermatozoa stored in this medium is akin or higher than that of fresh spermatozoa, and being entirely devoid of biologically-derived components, its use will expedite sperm imports, facilitating the dissemination of valuable genetics across the globe. These improvements will translate to an increased rate of genetic gain, improved welfare and enhanced economic stability for this sustainable, culturally significant industry.