MiradaAcres - 6/3/2019 16:14

I select the bulls I want to use and they provide the list of best potential mates.

Example:
Data for our cows is loaded in database. I give list of bulls I would like to use (several from my tank and several I am considering adding to the tank and some suggestions from the AI rep) . They then run all cows on all the bulls in our list and we get a list of mating suggestions (1st,2nd,3rd) based on our criteria. I suppose one could run all their cows against all the bulls and select ideal for each, but servicing 100 cows with 100 different bulls does not work well for semen costs since you have a lot of unused units.

And in 10 years your genetic variation is what?
Less than today.  The goal is to raise a uniform set of cows that works for us which means less variation in our herd.

(I think we do need at least some genetic variation.)
There will continue to be genetic variation since what works for my herd may not work for your herd.  We each have to breed to make profitable cows for our own operation. One dairy may focus purely on milk and net merit, another on sire conception and type, and another on feet and legs, productive life, and components; the point being what works for one does not necessarily another.  This is why stud companies sell a wide variety of genetics.

There are several times that we see a new potential bull that we would like to use and a poor fit for our cows due to high inbreeding coefficient and only working for one or two individual animals.  In this case we kick the bull out even if he has top numbers just because what do we due with the extra units of semen. Sometimes you pick the best and buy a rack for just one breeding because of the numbers.  The point is your genetic test and know what you have and which mating will most likely get you what you want.  It is parental averages with correction base on actual numbers.

Imagine flushing a cow a couple times to a bull and getting 30 live heifer calves that are full siblings.  Take those 30 heifers and mate them using conventional wisdom to a list of 20 bulls and mating suggestions will all be to the same bull since they have the same parental averages; genetically test those same 30 heifers and mate them to the same list of bulls and you could vary well end up with 20 different suggested bulls to use since in reality they are not identical siblings but rather unique heifers.  The more identical their parents, the more uniform the siblings will be but there will still be variation (maybe 10 bulls stand as 1st choices).