Puberty in the Welsh stallion.

This research paper investigates when puberty occurs in Welsh pony stallions, examining related physical and behavioral changes, as well as observing the influence of seasonality on these processes. The study also aims to define the time connection between the start of androgenic and gametogenic in testicular functions.

Research Objectives

• The study seeks to understand the sexual development of living pony stallions from birth until the occurrence of spermatozoa in their ejaculates.
• Another goal of the paper is to analyse the time correlation between the initiation of androgenic and gametogenic functions in testicles. These are key indicators of sexual maturity in male horses.
• The effects of seasonality on puberty and semen composition were also examined in the context of this research. This could reveal if environmental changes like daylight lengthening impact sexual development.

Methodology

• The materials for the experiment were four Welsh stallions from the research unit’s herd. Three of these were monitored from birth, while the fourth was observed from the age of 15 months.
• The foals were weaned at 6 months and examined at 9 months (during mid-winter). It was noted that the testes were very small at this time and male behavior was not evident.
• Six weeks later, with longer daylight hours, the testes had grown in size and male behavior became apparent. This aligns with past observations on the behavior of young stallions.
• Semen was collected every week from the younger stallions until spermatozoa appeared in the ejaculate and from the older stallion from 15 to 27 months of age.
• The research measured various aspects of the ejaculate, including the volume of semen, the sperm density, and the citric acid concentration. The time interval between the stallion entering the ‘teaser’ paddock and ejaculation was also logged as the ‘reaction time’.

Results

• The ejaculate volume and citric acid concentration in the three younger stallions gradually increased over time, with the reaction time initially being longer but then developing a pattern that shortened as citric acid concentration increased.
• The seminal volume and citric acid concentration increased steadily from 5 ml and 2 mg/100 ml at the first attempt to 9 ml and 4 mg/100 ml 4 weeks later, further increasing to 18 ml and 14 mg/100 ml 12 weeks later.