Variance in Stallion Semen Quality among Equestrian Sporting Disciplines and Competition Levels

Abstract

Most stallions within breeding programmes are expected to breed and compete concurrently. The exercising of stallions with regards to training regimes during the breeding season is a controversial subject. Daily exercise at low intensities is important for the mental and reproductive well-being of the stallion, however higher intensities of exercise, as seen in competing stallions, may have detrimental effects on seminal quality. To calculate if competition does affect semen quality, this study investigated the effect that equestrian discipline and timing of competition had on a range of stallion semen characteristics. This was a retrospective study that evaluated the seminal data of 1130 stallion semen collections from two UK based stud farms between 2009 and 2016. Competing stallion semen quality was significantly lower with regards to concentration (p < 0.05) and progressive motility (p < 0.05) than non-competing stallions. Semen volume was higher in competing stallions (p < 0.05) than non-competing stallions. There was a significant difference in seminal attributes among disciplines and competition levels (p < 0.05). The difference in semen quality among competing and non-competing stallions, as well as the difference among disciplines suggests endocrinological and physiological changes occur in relation to training intensity and competition.

Age-related linear and nonlinear modelling of semen quality parameters in Miranda donkeys

“…This contrasts the finding in horses by Wilson et al (2019), who suggested that younger stallions aged 2-4 years had 24% lower total and 21% gel-free ejaculate volume than stallions aged 5-9 years, while 10-14 years stallions presented 27% lower total and gel-free ejaculate volume. However, in young stallions (2 to 4 years) sperm concentration was 30% higher when compared to stallions aged 10-14 years.…”

“…This decline has been attributed to ageing stallions being more susceptible to substandard spermatogenesis and testicular degeneration. However, although previous research had reported stallion fertility to be optimal at 5-9 years, Wilson et al (2019) observed an increase of 23% in the total progressively motile sperm of stallions below the age of 20 years old, when compared to stallions aged 5-9 years.…”

“…For horses (Wilson et al 2019), age was found to significantly influence the quality of the seminal characteristics investigated, with a marked improvement in semen quality (sperm progressive motility, sperm concentration, sperm count and total progressively motile sperm) associated to stallions aged 20 years and above. These results differ from previous research within commercial breeding stallions, for which declines in semen quality by the age of 10 years have been consistently reported.…”

Dual use of breeding stallions is possible without affecting the sperm quality

“…Consequently, many stallions, especially at younger ages when they do not yet have a large number of competition‐aged offspring, are subject to dual use: They perform at high‐level sports competitions to improve their market value and are used as breeding stallions within the same season (de Oliveira & Aurich, 2021). It has, however, been established that active participation in competitive sports represents a considerable stress factor for horses (Cayado et al, 2006), which does not only have potentially negative effects on the overall health of the animals (Hardy, 2017) but has also been shown to significantly reduce sperm quality (Wilson et al, 2019).…”

“…cortisol, semen preservation, show horse, sperm quality, stallion semen, stress only have potentially negative effects on the overall health of the animals (Hardy, 2017) but has also been shown to significantly reduce sperm quality (Wilson et al, 2019).…”