Refining the Reproductive Tract Scoring for More Assertive Selection of Beef Replacement Heifers

Commodities

Practices

Reproductive tract scoring (RTS) assesses the reproductive maturity of heifers by transrectal palpation of ovarian structures and uterine size and tone (1-3: prepubertal status; 4-5: puberty). Although widely used, it is subjective and poorly predicts fertility when heifers are treated with progesterone-based synchronization protocols for artificial insemination (AI). These treatments can induce puberty and improve conception rates in previously prepubertal heifers, making current RTS classifications unreliable. Moreover, RTS does not accurately reflect maternal fertility potential-many prepubertal heifers perform as well as pubertal counterparts.

This project will use transrectal ultrasonography before and after progesterone treatment to better characterize ovarian and uterine development, relate these changes to pregnancy outcomes, and link phenotypic and genomic fertility markers to improve heifer selection accuracy.

Research will be conducted with cooperating Missouri cow-calf herds and integrated with the Show-Me-Select Replacement Heifer Development Program. Producer and veterinary workshops will demonstrate ultrasound-based scoring as a practical, objective tool for field application. By refining RTS and advancing fertility and maternal prediction, this project will enhance reproductive efficiency, shorten calving seasons, and improve economic sustainability for small and medium-sized beef operations across the North Central region-combining reproductive physiology, ultrasonography, and genomics into a producer-driven innovation.

This project will refine the RTS system to improve the selection of fertile beef replacement heifers. Specifically, we will: (1) use ultrasonography to characterize ovarian and uterine variability within RTS classes before and after progesterone treatment; (2) relate these changes to pregnancy outcomes to identify heifers with inducible puberty; (3) enhance the accuracy and objectivity of RTS in predicting fertility; and (4) associate reproductive phenotypes with genomic maternal productive traits (e.g., stayability, fertility). Outcomes will support more reliable heifer selection tools and producer education across Missouri cow-calf operations participating in programs such as Show-Me-Select Heifer Development.