Performance versus progeny or sib testing.
In a performance-testing scheme, the traits of
interest are recorded directly in every individual.
For example, body weight and growth are often
recorded over a fixed period during the lifespan
of beef cattle, pigs, broiler chickens or turkeys.
Basically, a cohort of animals is managed together
under similar conditions over a period of time
during which individual performance is measured.
This can be done on the farm, or at a performance
test station where cattle or pigs from different
herds or farms are brought together for a direct
comparison under the same conditions.