Want to select bulls with a heavy emphasis on semen fertility? This is your category! While the greatest variables affecting pregnancy rates are accuracy of heat detection, inseminator technique and other management factors,looking at all available fertility values of individual sires can help. Through evaluation of the Composite Fertility Index (CFI) and Sire Conception Rate (SCR), along with intense semen quality evaluations, these elite sires earn the designation of Superior Settler.
Some A.I. organizations currently are attempting to make quite an issue of semen fertility, as if measuring fertility were a new concept. They are right in saying you should buy the highest fertility semen that you can. However, the system to which they are pointing for comparison – Estimated Relative Conception Rates (ERCR) – was not designed to compare bulls between studs. Too many regional management factors can make comparison by ERCR between studs rather unreliable. For decades Select Sires has published information about the fertilizing capacity of semen from our bulls. Just as there are differences in genetic-transmitting ability between bulls, so are there differences in the fertilizing capacity of spermatozoa from different bulls. Select has created the Superior Settler listing to recognize those bulls that have achieved a superior fertility index that ranks them among the elite fertility bulls in the Select Sires lineup. Only the top 25 percent of Select’s active lineup is designated with Superor Settler status. This does not mean that 75 percent of the lineup has semen that is poor quality. It simply means that they don’t rank among the top 25 percent of Select’s lineup. The standards that each and every bull must meet illustrate why Superior Settlers are truly elite fertility bulls among a very competitive group. First, each bull housed at Select Sires has been given the very best housing and health care available. Second, semen has been collected, processed, packaged and frozen using the latest scientific technology. Then a sample is thawed and re-evaluated to determine whether the proper numbers of motile spermatozoa for optimum fertility are present. The sperm are also evaluated to see whether they are morphologically normal. If the quality standards are met, then the semen is released for sale. Next, cows are inseminated and fertility information is sent back to Select Sires. This information is computed and analyzed, and a non-return rate is generated. The non-return rate is the percentage of cows that Select Sires representatives have reported for first-service insemination and not reported for a second-service insemination within a defined period of time. The Superior Settler designation is based on six months of historical semen-quality data (including post-thaw motility, incubated motility, incubated intact acrosomes and spermatozoa morphology) combined with current non-return data in a model to provide an index. The highest 30 to 40 bulls in the lineup are considered further. If an individual bull has a lower-than-average non-return rate, he is removed from the Superior Settler list. Bulls that have a six-month history of above-average non-return rates, even though they do not place in the top 40 percent of the index list initially, are elevated in status. Because great emphasis is placed on semen quality traits during the previous six-month period, Superior Settlers can be considered more of a “predictive” estimate of what fertility will be on bulls in the next few months. As the program has developed, there are usually about 16 to 18 bulls identified as Superior Settlers that have non-return data of their own. Plus, there are about six to eight bulls that have no non-return data, but have significantly high semen quality values that earn them the Superior Settler designation. Select Sires always strives to keep you updated on the fertility status of our bulls. If you have a concern about fertility, Select Sires offers the most well-trained field staff and a team of reproductive specialists that can be a tremendous resource to you.