|2015 Genetic Base Changes for Goats – Production and Type Traits|
The base change for each trait is defined as the difference between the average predicted transmitting ability (PTA) of does born in 2010 and the average PTA of does born in 2005. Stepwise genetic bases allow predicted transmitting abilities (PTA‘s) from new evaluations to be easily compared with previous evaluations except at base changes, when accumulated genetic gain is subtracted so that all animals are compared with a more recent doe population. This keeps the PTA from becoming inflated over time so helps describe the expected genetic improvement. This base changed was implemented for recent evaluations and compensates for progress made since 2010. Updated bases show how much each animal is superior or inferior to the current population. The average PTAs for sire identified does born in 2010 in each breed were set to zero. When genetic trend is positive the mean PTA decreases with the base change then remains fairly stable until the next base change which would be in 2020. A particular animal’s PTA is supposed to decrease when the base is changed and remain fairly constant between base changes.
Genetic progress for yield traits (2010-2005)
Genetic progress for type traits (2010-2005)
|Fore udder attachment||-0.38|
|Rear udder height||-0.86|
|Rear udder arch||-0.65|