How much can a bull add?

[Air gator]

If you have a heifer/cow that doesn't produce enough milk how much impact can a bull have on daughters?
How much improvement will there be or in other words can a bull "fix" the problem and have daughters you want to keep?

Likewise, how much impact can a bull have on Scrotal from a cow to his offspring?

Are these traits that require 2 or 3 generations to fix/change?

This is assuming that the heifer/cow has other qualities that you value.

Thanks.

 

[cow pollinater]

Milk is not a highly heritable trait. I think I remember 15% heritability. The impact from one generation of corrective mating could be anywhere from unnoticed to way off in the extreme other end or anywhere in between. Milk is a perfect example of a trait where you want to pick an ideal and move to it with every mating. At 15% you can chase your tail in circles trying to get to the right spot as it would take a couple generations to show improvement either way and then it would likely be to much if you really got after "improving" them.
Scrotal is a little more heritable but not worth worrying about.

 

[Ebenezer]

Remember the bell curve.

 

[Son of Butch]

Milk is by far the least heritable trait at .12 (12%) (from angus assoc website)
breed average for milk is 24 and 12% of average would be a change of plus or minus 3

Scrotal is tied for 2nd highest heritable trait along with marbling at .48 .... both behind stature... yh .51 mh .62
Scrotal is much easier to change than milk in one generation....

my guesstimate would be a 20 percentile change could be made in one generation.
ie offspring of a breed average animal could swing up to top 30% or drop to bottom 70% in one generation for scrotal

 

[Air gator]

Thanks CP and Butch,
I have a hard time trusting the current Angus epds.
I keep looking at the marbling epd and talk about a moving target.
The only thing that seems consistent is that the GAR bulls keep improving.
Connealy Comrade, at one point, was +1 for marbling and +1 for ribeye.
He's now +.56 for marbling and +.68 for ribeye.
There are a lot of young bulls that start out with great epds for CED and you can look at them and
you know they are not heifer bulls. You can understand that but when they change ALL the epds it makes you wonder.