Why are EBVs different for littermates?

The PennHIP score, Harness Sensitivity testing, Thunderstorm Fear via the survey Guiding Eyes used and that they used it on all/most dogs through their lifetime means these traits have higher estimates of heritability because they are typically measured and scored consistently.   All 3 of these traits respond quickly to selection.

Additional measures of behavior by scoring BCLs at various age points using effective and consistent ways to measure the dogs will also increase the heritability of many of the behavior EBVs.  We know that because the IWDR estimates of heritability for Labradors is much lower than what Guiding Eyes has estimated.   It would be very helpful if individuals within organizations and between organizations are using consistent measures and scoring accurately – this is one of the goals of our BCL certification testing through the IAABC.  

12 months is not the ideal age for hip and elbow radiographs.  It would be best if these were done a little older if possible. 

The permanent environmental effect is changes in behavior influenced by the environment which stay with the dog but are not passed on to the offspring.  Some examples are the skill level of the puppy raiser while training and reinforcing the training and level and quality of socialization opportunities especially during the most critical period of birth through 16 weeks.