The adjusted weaning weight calculations in CattleMax are based on the Beef Improvement Federation (BIF) standards. Page 18 of the BIF Guidelines document (http://www.beefimprovement.org/library.html) has the formula and page 17 has the age-of-dam adjustments that CattleMax uses for the calculations.

The age-of-dam adjustments can be changed by clicking the Settings button in CattleMax, choosing Preferences then clicking the Herd Adjustments tab.