I have my own (paper-based) system. Well, a card index actually. Every registered pedigree breeding animal has a card with details of dam, sire, date of birth, registration details and so forth. I also add information on lambing, using: oho - on her own; jap - just-a-pull; gm - good mother. I also add notes on how well the lambs did. It does allow me to trace back six generations and follow trends in the flock. I've culled out triplet bearers, poor mothers, prolapses, consistent small twins and mastitis - without mercy. Lambing has become easier every year and for my main breed, the Southdown, things like carcase are low on the list of priorities, as they all have a good carcase. I have bought a ram with high EBV's, just to see if there was an appreciable difference between his offspring and those of ones I'd previously selected by eye and feel, and there was no discernible difference in his lambs' growth rate or any other aspect.