Another assumption in NSE analyses was that sires are mated randomly, that is, to females of equal genetic merit. This may not be true, depending upon the intent of a particular breeder. And finally, it had been assumed that progeny were not selected or culled before all records are collected. In most operations some animals for which weaning information is available are not maintained for further collection of performance data. This results in a changed contemporary group average which is the basis for all comparisons.
All breed programs evaluate certain traits.
The expected birth weight deviation of calves from this individual, excluding maternal influence. In other words, this would be the relative birth weight with equal uterine conditions assumed. This, then, is the genetics passed on directly to progeny by this individual only for weight at birth. Weight at 205 days of age of calves sired by or out of this individual excluding maternal influence, i.e., as if produced by and reared by the exact same cow under the exact same conditions. Weight at 365 days of age with maternal influence excluded .