Introduction to Sexed Semen
The use of sexed semen has become increasingly common within the livestock industry, largely due to improvements in technology, reduced costs, and improved pregnancy rates. Sexed semen can be utilized as a tool to generate more calves of a desired sex, and in the process, improve the genetic merit and production efficiency of a herd. Beef producers can take advantage of female sexed semen to generate replacement heifers from their best performing cows, or male sexed semen to generate male calves for seedstock or beef production purposes.
When compared with conventional semen, sexed semen has been previously shown to have decreased pregnancy rates. However, recent research indicates that conception rate differences between sexed and conventional semen can be decreased through the use of estrus synchronization protocols tailored for sexed semen. A group of Reproductive Specialists from Universities across the USA, known as The Beef Reproduction Task Force, publishes a list of recommended protocols for use with sexed semen that gets updated yearly[i]. Beef producers can now take advantage of these specific synchronization protocols in order to achieve greater pregnancy rates with sexed semen in the field.
ABS Sexcel® Technology
ABS’ sexed product is called Sexcel® and is produced using cutting edge laser technology from IntelliGen® Technologies. Sexcel® is manufactured in a unique way using a technology platform containing low-pressure, continuous stream microfluidics. During the semen sexing process, unwanted male or female sperm cells are ablated (destroyed), depending on what the desired sex is. Sexcel® straws, therefore, contain both live viable sperm cells (predominantly the desired sex) and sperm cell fragments (predominantly the undesired sex). ABS Real World Data® has shown Sexcel® to be the highest performing sexed semen product in the industry and has now been used in over 3.2 million inseminations in the ABS Real World Database®.
Quality control
Sexcel® sexed semen undergoes a rigorous four-step quality control process before the semen is qualified as suitable for sale. These quality control steps include analyses of post-thaw insemination dose, sex skew percentage testing, genomic sire verification, and bacterial testing for unwanted pathogens. Therefore, producers can rest assured that they will receive a consistent sexed semen product with exceptional quality.
Strategic use of Sexcel® to make replacement heifers
Producers that utilize Sexcel® technology have the opportunity to purposefully select sires with greater maternal traits and generate superior replacement heifers. When selecting these sires, producers can focus on traits associated with fertility, milking ability, maintenance cost, and longevity. Moreover, by combining the use of female sexed semen and estrus synchronization, more replacement female calves can be born closer to the beginning of the calving season. These replacement heifers are then not only genetically superior for maternal traits, but are also older by the start of their first breeding season, which increases their chances of becoming pregnant.
Sexcel® 60/40 Synch Strategy
ABS has developed a fixed time insemination strategy called the 60/40 Synch which combines the use of estrus synchronization, female Sexcel® semen, and conventional semen to maximize the productivity and efficiency of a commercial cow-calf herd.
When following the 60/40 Synch, fixed-time AI is performed in females that have expressed estrus (approximately 60% of the herd) using female Sexcel® semen from maternally oriented sires, whereas females that have not expressed estrus (approximately 40%) are inseminated with conventional semen from terminally oriented sires, such as those of the ABS NuEra™ line. Clean-up bulls with terminal traits are then used to breed the females that did not conceive to artificial insemination. The resulting calf crop will be approximately 35% maternally-designed replacement heifer calves sired through sexed semen and 65% terminally-oriented bull and heifer calves sired through conventional semen and natural service.
Through this strategy, producers are able to target the production of maternally designed replacement females from their early calving cows and are then able to focus on adding more pounds and terminal value to their remaining calf crop. ABS NuEra™ sires are selected to maximize feeding performance, feed efficiency, carcass quality, growth rate, and carcass yield and are therefore a good option to use as terminal genetics.
Conception rate differences between conventional and sexed semen are minor between females that express estrus. Most differences in conception rates between conventional and sexed semen are observed within females that do not express estrus prior to fixed time AI; therefore, by utilizing the 60/40 Synch, commercial cow-calf producers can purposefully generate superior female replacements and terminal steers and heifers while maintaining good pregnancy rates.
In Summary
Improvements to sperm sexing technology are continually being made and will likely lead to further improvements. Research into fixed-time artificial insemination strategies for sexed semen has resulted in greater pregnancy rates with sexed semen, yet further research is required to obtain pregnancy rates similar to those of conventional semen. Nevertheless, a list of recommended estrus synchronization protocols for sexed semen is available from the Beef Reproduction Task Force and can help producers minimize differences in fertility between sexed and conventional semen.
Together with genetic selection, the use of sexed semen is a good strategy to produce genetically superior male or female calves of the desired sex. In addition, the 60/40 synch strategy can be used to generate superior female replacement heifers and more terminal offspring, and can help maximize herd reproductive efficiency and profitability, particularly when used with Sexcel® sexed semen and NuEra™ genetics. For more information visit www.absglobal.com, visit our social media channels or call 1-800-ABS-STUD or 608-846-3721.