How much genetic influence does a bull have?

[CIW]

I was reading a reprinted article from the UNL extension agency. All my life my papa told me that a bull genetically weighs in at 50% of the herd genetics. UNL surmised that it was much different. They say it can be upwards of 87.5%.
What do you all think?

[randiliana]

It would depend on the genes he's passing on... If he has mostly dominant genes, he would have a bigger effect than a bull who passed on mostly recessive genes.

If you considered it on a cow to cow basis, you're right he'd only have about a 50% influence.

However, what I would imagine that they are talking about is on a herd level. A good bull can improve a lot, where as a poor one would do the opposite, if you figure each bull breeds 25-30 cows, he has a lot more influence, than any 1 of those 25-30 cows.

[Allen W]

If your keeping your own replacement heifers he'll have a considerable effect on your herd for years to come.

[CIW]

I went back and read it again. I didn’t find the article to be one for choosing the type of gene needed as much as a profile to influence the bull battery has on the herd genetics.
They used an example of a producer that purchased 3 bulls every 3 years. 3 in 2012, 3 in 2009 and 3 in 2006.
You save back15 replacement heifers from your 2013 crop. On average they will carry ½ their genes from the 2012 bulls, ¼th of their genes from the 2009 bulls and 12.5% from the 2006 bulls.
If you had 100 producing cows that would mean that the 2015 calves would be 87.5% genetically related to the last 3 groups of bulls previously purchased.
I’m not down playing the importance of a good maternal side to your herd. It does reveal how important to the future it is, to the selection of quality bulls that possess the ability to pass on attributes that you want..
This made me see just how the use of EPD’s (expected progeny differences) is such an important part of the purchase of bulls.
From this paper I can see that I need to make some management changes in order to progress in maternal side of my herd.
Although I feel like I produce some good calves, If I change from a terminal production to a partial replacement production my cattle have a potential to become better
By purchasing replacements I am diluting the power my bulls have on my calf crop.

[BobbyB]

Growing up and well beyond I always heard that you can have so so cows and a really good bull and will get good calves. Have good cows and a really good bull and get really good calves.

I guess thats in laymen's terms, but the point is, a good bull is usually more than half the calf. But it doesnt matter how good a calf the cow has if she dont give enough milk to raise him.

We always had average to good cows, but bought the best bulls we could find.

[Allen W]

Originally Posted by BobbyB

Growing up and well beyond I always heard that you can have so so cows and a really good bull and will get good calves. Have good cows and a really good bull and get really good calves.

I guess thats in laymen's terms, but the point is, a good bull is usually more than half the calf. But it doesnt matter how good a calf the cow has if she dont give enough milk to raise him.

We always had average to good cows, but bought the best bulls we could find.

A number of years ago a neighbor changed from the usual canon ball headed narrow butted polled herford bulls to using half decent brangus bulls and thought he won the lottery. Of course he thought the brangus bulls were expensive compared to the junk he had been buying.

[CIW]

Bobby,
That was my reasoning for mentioning the use of EPD's. I can use them to help screen replacement bulls for whatever traits I need.
If I wanted high milk and maternal traits in a virgin bull, I have that ability to specifically get those traits into my replacement heifer's.

[DaleK]

I always figured a good bull for 50% influence and a bad one closer to 100%

[BobbyB]

Originally Posted by CIW

Bobby,
That was my reasoning for mentioning the use of EPD's. I can use them to help screen replacement bulls for whatever traits I need.
If I wanted high milk and maternal traits in a virgin bull, I have that ability to specifically get those traits into my replacement heifer's.

Back in the days I refer to, I am sure EPDs were available, but we never looked for or asked about such.

As I said we used the best bulls available, kept the cream of the crop for keeping heifers and sold every thing else.

It worked just fine for the nearly 60 years my family ran that ranch. And when it was sold, it wasnt because of the cattle.