Holstein Plaza

Two changes have been made. The first change is that they’ve discovered a mistake in the August genomic evaluations that mostly impacted PL but to a small degree DPR also. All bulls with daughters in at least 10 herds get used in the predictor group for calibrating genomic evaluations. Some of these bulls that are early progeny test bulls or foreign bulls do not have progeny proofs for DPR and PL. It turns out for these bulls they were using their gPTA for PL and DPR in solving for the SNP effects rather than using the traditional PA values. This was corrected back in September. The changes memo said this only had a small effect on PTA values but it had a big impact on PL and DPR reliability values. We will see reliability values for PL and DPR decrease by 6 to 8 points from where they were in August.

The second change is the implementation of new trait correlations in the calculating the multitrait PL values. These are fairly self-explanatory; SCS, DPR and Body Size now have more influence on PL and Udder Composite and Feet & Legs Composite have less. This change also reduced PL reliability because the traits receiving more weight tend to have lower reliability values.

We will see some bulls making big changes for PL in the December run which means big changes in NM$ and TPI/JPI. The top 100 Holstein young sires for NM$ on average changed -0.9 for PL. This means we will likely see some individual young bulls changing by -2.0 PL. A decrease of 2 for PL translates to a loss of 70 NM$ and 47 TPI points. (click here for more details from USDA)

~A special thanks to Scott Culbertson and Chuck Sattler, Select Sires, for submitting