Archive for Sire Stack

Dairy Cattle Genomics: Have we taken it too far?

When you look at the top 10 GTPI heifers you see that 9 of them are from heifers themselves with only one coming from a scored and milk producing dam.  In addition 9 of them are from one sire (Shamrock), which instead of widening the genetic pool is actually shrinking it.  Looking at the top GLPI list reveals that three out of every four in the top 100 are from un-calved heifers.  While, on paper, cutting the genetic interval makes sense (read The Genomic Advancement Race – The Battle for Genetic Supremacy), long term, have breeders and AI companies started to take it too far?

In the new genomic world the previous gold standard of a proven sire stack and string of VG+ is no longer required.  In any given pedigree you can now find GP cattle (read Is Good Plus Good Enough) or sires that you never have heard of.

Does Classification Even Matter?

While GP-84-2YR used to be the kiss of death for many marketing and genetic programs, genomics has changed the game.  With genomics, we are seeing many GP 83 or 84 cows used as dams that would have never been touched before.  While many will increase in score later in life, others do not, and yet that does not seem to be as big a factor.  Many A.I. companies and breeders are more concerned about their genomic values than that of the actual classification scores.

There could be many reasons why that potential bull mother did not score very good.  It could be management, it could be an accident that happened.  Also, it could be that she is just not that good.  It brings into question the relevance of classification.  While the index system relies on having a large data set in order to map the genomes to the potential performance of each trait, it has me thinking do we need to score cattle anymore or can we just use their genomic values?  Then I snap back to reality and realize that it’s one thing to look good on paper and another to deliver in reality.

Have We Forgotten Sire stack?

At one time, if there was a non -known sire in the pedigree, A.I. would not touch it.  The marketability of that pedigree was next to nothing.  No matter what the classification score was, or what the family was behind that animal, sire stack carried significant weight.  Now I find myself having to do as much homework on the sire of the new top young sires, as I do on the young sires themselves.  That may be because most of them are still young sires themselves.  However, it is also because a young sire that did not turn out can still sometimes be better than a previous Top 10 proven sire.

For example, let’s say the proven sire has a TPI of 2300 at the time of mating and the young sire being used as sire of sons has a TPI of 2900.  By the time the resulting progeny is being sampled the proven sire may have a TPI of 1750, and the young sire that was being used as a sire of sons may have a TPI of 1850.  While that young sire may not be a list topper anymore, he is still higher than the proven sire that could have been used at the time.

The Bullvine Bottom Line

The dairy cattle industry has seen more change in the selection of parents in the past four years than at in any other period in its history.  Genomics has changed the name of the game, and while many breeders have been apprehensive in embracing it, others have taken it and are running full force.  I would not be surprised to see more significance in the future put on Direct Genomic Values (DGV’s) than on the weighted GLPI or GTPI.  With everything that is new, there is a learning curve and, as we discover how to use this tool better, I am sure we will find better ways to apply the information.  However, there is no question that genomics is here to stay and it is greatly changing the rate of genetic gain.

The Dairy Breeders No BS Guide to Genomics


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