Ultrasound & Fertility Testing
Over the last 14 years, Midland has collected as much if not more ultrasound data than just about any other location in the country.
All test bulls, not just sale bulls, are ultrasounded so that a complete comparison can be made amongst all the bulls evaluated on test. Collection of ultrasound data is done in accordance with the guidelines developed by the Ultrasound Governance Committee, which oversees ultrasound matters for the U. S. Beef Breeds Council. The images collected are submitted to UltraInsights, a centralized ultrasound processing lab. All bulls enrolled in their respective breed association’s performance program have data submitted to the breed association so that the ultrasound data is incorporated into genetic evaluation for the breeder. In that way, the most up to date EPDs are available for the bulls prior to the sale. Ultrasound results will be listed in the sale catalog and on our web page.
A major objective in a cow-calf operation is to produce one calf from each cow annually. The degree to which producers meet this goal influences their net income. A key component of efficient calf production is a high fertility level in each breeding animal in the herd. Since individual bulls service many females, a deficiency in the breeding ability of one bull has a larger impact on herd productivity than fertility problems in a single female. Using a subfertile bull may lead to longer calving intervals, a lower number of calves produced and increased costs from wintering open females. All of these results cause serious economic loss to the cow-calf producer.
It is not feasible to determine true fertility before a bull is used in the herd. Nevertheless, a bull can be evaluated for breeding soundness and this information used to assess his potential fertility. A few bulls may be sterile, but most have fertility levels ranging from very high to very low.
All sale bulls must adjust to a minimum of 32 cm testicle size at 365 days of age.
Measuring the scrotal circumference of young bulls is an accurate, repeatable method to assess current and future sperm-producing ability. The measurement gives an estimate of the weight of the testes, which is directly related to the level of sperm production. Scrotal measurement is also positively correlated with semen volume and quality. Bulls with adequate scrotal development for their age have a higher probability of becoming satisfactory breeders than bulls with smaller scrotal circumferences. Scrotal circumference is of medium to high heritability. Fertility of the male offspring can be increased by selection for this trait. The scrotal circumference of a bull is also positively related to the fertility of his daughters. Heifers from sires with larger than average scrotal circumference tend to reach puberty earlier than those from bulls with smaller scrotal circumferences. Increased scrotal circumference in sires is also favorably correlated to their daughter’s age at first breeding, pregnancy rate and days to rebreeding after calving.
The criteria commonly used to evaluate semen quality include sperm morphology (structure) and motility (rate and percent of progressive forward movement). Semen volume and concentration can also be used.