Every year, countless horses make the transition from a competitive athlete on the harness track to a life as a broodmare or breeding stallion. But will their years on the track and accompanying stresses impact their breeding careers? According to the results of a new study from Finland, it’s unlikely that racing has an effect (either positive or negative) on horses’ subsequent breeding careers, specifically their fertility.

Jenni Sairanen, MSc, a PhD candidate at the University of Helsinki, and colleagues reviewed the racing and breeding records of more than 60,000 Standardbred and Finnhorse mares and stallions (from 1991 to 2005) to see if and how competitive harness racing careers affected their fertility.

After analyzing foaling outcomes and racing performances, the team found that overall, each mare’s racing career had little effect on her future breeding career, and in some cases, some time on the track was beneficial to subsequent pregnancies.

"The mares with a small number of races get all the advantages–conditioning, feeding, and attention–but not too many of the disadvantages, like stress (which can decrease a mare’s chances of becoming pregnant)," Sairanen said