A three-year study compared growth and breeding-soundness measures in 114 yearling bulls.
Two feeding targets
A research abstract published on 29 September 2026 reports a three-year trial involving 114 yearling MARC II bulls. All received the same basal total mixed ration for 112 days, with feed amounts set for target gains of 1.8 or 1.13 kilograms per day. Actual average gains were 1.7219 and 1.1617 kilograms per day, respectively.
Breeding-soundness measurements
At day 112, the faster-gaining bulls had larger scrotal circumference. The researchers reported no significant treatment difference in total, motile or progressively motile sperm counts in the measurements described. The publication is a conference abstract, so the reported comparison covers these measured traits rather than subsequent pregnancy results.