Managing stallions who compete alongside breeding duties *H&H VIP*

Party Trick could be excused for having a bit of a swagger. Nick Gauntlett’s home-bred five-year-old stallion, a son of Badminton and Bramham winner Chilli Morning, is already making his mark in Burghley young event horse classes and is on his way to BE100. In addition, he can boast a grading as a champion stallion with Sport Horse Breeding of Great Britain and last year sired his first crop of foals.

Combining a competitive career with breeding duties was something his own sire accomplished with ease, but can Party Trick do the same? Managing a stallion that excels in both activities is certainly possible, but requires expertise, organisation and a thorough healthcare programme.

Good nutrition is crucial not only to maintain healthy condition for fertility, but also to provide the stallion with the energy required to compete. Feed intake will depend on an individual’s competition level and his optimum body condition. Some larger stud farms employ nutritional consultants to tailor each horse’s balance of energy, fat and protein. Vitamin E and ascorbic acid are recommended as a supplement, with some studies showing this to be beneficial for improving the quality of chilled or frozen semen.

The typical stallion will consume 2% to 3.5% of his bodyweight as dry forage. Ideally, he should be kept in a fit, athletic condition throughout the year. It is helpful to monitor his weight regularly, using scales or body condition scoring to record and highlight any fluctuations. Over- or under-conditioned stallions are more prone to gastrointestinal and orthopaedic conditions, such as laminitis, in addition to reduced libido and sperm longevity, and behaviour issues that could affect semen quality. With a competition stallion, exercise is therefore advantageous in maintaining correct bodyweight.

Sound feet are crucial for both competition and breeding duties. Hoof trimming may be necessary more often than the standard six to eight week intervals. Appropriate worming and dental checks are also necessary, along with annual vaccinations for equine influenza and tetanus. Stallions, particularly those that have been imported or worked abroad, may have been vaccinated against viruses such as equine herpes virus (EHV) 1 and 4, and equine viral arteritis (EVA).

All stallions intended for stud work really should have a thorough annual breeding soundness exam. Two sets of swabs are taken from the penile shaft, prepuce (foreskin), urethra and pre-ejaculatory fluid, at seven-day intervals, to detect sexually transmissible diseases such as contagious equine metritis (CEM, or Taylorella equigenitalis), Pseudomonas aeruginosa and Klebsiella pneumoniae. Blood tests are also taken for EVA and equine infectious anaemia (EIA).

Dummy run

As the breeding season nears, the stallion should ideally undergo a thorough reproductive exam. This procedure includes palpation and ultrasonography of the testicles and accessory sex glands. Semen is then collected by an artificial vagina using a dummy mare.

There is significant variability within stallions regarding fertility — and even more so for how the sperm reacts to the extenders that prolong its life and the processes required for chilling and freezing. The stud will determine the optimum temperature and pressure for the artificial vagina used for collection, along with the best type of extender and cryoprotectant (if freezing) for each stallion.

Semen evaluation is performed by microscope; the concentration of sperm, its motility (movement) and morphology (structure and shape) are checked for any abnormalities that may reduce fertility. These could be primary defects of sperm production or secondary, due to problems involving increased environmental heat or lack of recent breeding activity. More advanced testing is employed at the larger AI centres to assess the DNA structure and plasma membrane of the sperm.

Overall, the results dictate how the stallion should be used within an artificial insemination (AI) programme to maximise fertility and conception rates.

A fine balance

Being in peak competition condition can boost a stallion’s libido and benefit his breeding career. Yet keeping him mentally and physically fit without his exuberance posing a danger to handlers and other horses can be a fine balancing act.

Juggling competitions around a regular AI collection can be difficult. In addition, strenuous exercise, stress at events and heat can negatively affect sperm production and, therefore, fertility.

An alternative to making a stallion available throughout the season is to limit his time at stud. Set schedules require the mare’s oestrus cycle to be synchronised for these periods. As this may not be possible, frozen semen can provide an alternative, although at least 20% of stallions fail to produce semen suitable for freezing that can withstand the extenders, cryoprotectants and processes involved.

Injuries such as hindlimb strains can occur when a stallion is required to mount a dummy mare, so the collection area should have a soft but firm footing to prevent slipping. A padded dummy mare is generally considered safest for the stallion, rather than covering a mare “in season”. A kick to the stallion’s scrotum can be extremely serious and, at the very least, can curtail breeding for several weeks.

Maintaining a stallion with a level head, but with enough libido for breeding and fitness for competition requires experienced handlers and a safe environment. But it can be done — as Party Trick is proving.

Ref Horse & Hound; 25 January 2018