When deciding if a particular sire will be profitable within a herd, as in the first situation, a selection index that yields an estimated economic value is required. There's still a need for research, development and extension in the industry to help producers get the information they need to establish a useful sire-selection index, MacNeil says. The typical producer is going to need some help. Breed association personnel and Extension breeding specialists are good places to start. Scientists have not found a single set of recommendations establishing a sire-selection index that fits all producers.
Reproduction is one of the traits on which experts hold differing positions.
Some say fertile bloodlines have been naturally selected over time. Others argue reproductive inefficiencies have such a large economic effect that the lowest level of occurrence greatly affects profitability. Wallace doesn't include reproductive traits in his selection index. Scrotal size is the only indicator available, and he says it is only one small part of overall fertility. Conception rates for the sire are more important.