Breeding Soundness Evaluation of the Stallion
John Steiner
Hagyard-Davidson-McGee Associate PSC
Lexington, Kentucky USA

Assessing reproductive capacity of the stallion is a multifactorial process.  The Breeding Soundness Examination attempts to provide an estimate of a stallion’s future fertility.  The typical Breeding Soundness Examination consists of the following:

1.     Complete medical and reproductive history

2.     General physical examination

3.     Semen collection and evaluation

4.     Evaluation of libido and mating behavior

5.     Examination of the external genitalia and occasionally internal genitalia

6.     Bacteriological evaluation

7.     Ancillary procedures

Management of the stallion and mares also plays a large role in the fertility equation.  Unfortunately, no single seminal parameter correlates highly with fertility in the stallion.

It is the ancillary procedures that I would like to address in our discussion.  In my opinion, steps 1 – 6 above do not always give us an accurate assessment of the inherent reproductive capacity of the stallion.  I feel we should be looking in other directions to get a more complete picture of the “fertility” of the stallion.  Perhaps some of the areas we could discuss would be the following:

1.     Karyotype analysis

2.     Sperm-ova penetration tests

3.     Ultrasonography

4.     Acrosome evaluation

5.     Sperm chromatin assays

6.     Seminal proteins

7.     Endocrine evaluations

8.     Testicular biopsy

9.     New areas of research

 It is my hope that this discussion will at least get us thinking of newer and hopefully more fruitful ways to evaluate stallion fertility.  Perhaps, we can also discuss any thoughts on therapy for subfertility-infertility in the stallion.