The Adjusted 60 Day Weight Index is calculated as A Trait Index. All weights were adjusted to 60 days with corrections for type of birth, sex and age of dam. The index is then computed by dividing the average weight of all lambs into an individuals weight and multiplying by a 100 percent. Therefore, lambs that score 100 percent are average of the lamb crop, lambs that are over 100 percent are performing better than the average. Sixty day weaning weight is really a measure of ewes milking ability.
120 Day Adjusted Weight Index> is calculated in simular manner. The only adjustment is for age of lamb. Performance of the lamb after weaning to 120 days is used to measure the genetic potential of the the lamb to gain.
Composite Index is computed by using half of the 60 day wt. and half of the 120 day wt. and multiplying by 100%.