Pre-seasonal breeding evaluation of the stallion

Fertility of the stallion is an essential factor in the success of a breedi ng operation as good semen quality is a prerequisite for a good breeding pe rformance. Therefore, pre-seasonal evaluation of stallion reproductive perf ormance is of importance. In the Netherlands almost all breeding associatio ns require a breeding soundness evaluation before a stallion is registered as a breeding stallion. Each year more than 600 young (mostly three-year-ol d) stallions are evaluated on reproductive characteristics as semen quality and external genital organs (testicles and epididymides). Criteria for acc eptance of a stallion for breeding vary between breeding associations Semen evaluation prior to breeding has been proven to be a valuable test fo r predicting stallion fertility in the first breeding season. As a high num ber of mares (> 300) can be inseminated from one stallion insight in the se men production is necessary. Therefore, this production should be evaluated (for ten days) to estimate the daily sperm output (DSO) at the beginning o f the breeding season. In an Al-program the semen can be used either locall y, shipped to the mare-owners place or to another stud farm. Shipment of se men requires an adequate storage procedure to ensure minimal loss of semen quality. Semen can either be stored chilled (short term) or frozen (long te rm). The quality of semen after storage is highly dependent on the quality of the semen before storage and will at best approximate, but never exceed the quality of fresh semen. Therefore the storage ability of chilled semen should also be tested at the beginning of the breeding season. Then the man agement of the stallion can be adapted depending on the semen quality and t he number of mares to be served to optimize breeding results and minimize c osts.