Calf size verses profit

[cowman]

Hows the heredity on those traits? My old AI instructor always said the fastest way to change the makeup of a cow herd was to select for traits that have high heredity values and cull out the low heredity problems?
So for instance body frame has a high rate of heredity at.60 and calf birth size is also high at .45? Fertility is actually listed at a rate of .00 to .005, according to the American Breeders Service AI Management Manual! Can't seem to find one for longevity, don't know whether they consider it all that important.

[grassfarmer]

Too funny Cowman - "Can't seem to find one for longevity, don't know whether they consider it all that important." "They" being the American Breeders Service AI Management Manual -perhaps they have motives other than identifying cattle that will be profitable in the longterm for ranchers?

[cowman]

Well grassfarmer I don't know? They live and die by selling semen but I would assume they would like to see their customers prosper and continue to operate? I suspect it isn't a highly heredity trait...or at least one that can be measured?
I'm not saying longevity isn't a good thing. I have one old registered hereford cow that is 17 this spring. Now she sure doesn't bring the best calf home in the fall but with BSE she just seems to hang around. In the end she'll probably die here so there will be no salvage value. Does she owe me anything? No I guess she doesn't but I'd be real happy if I could get $600 for her! Better than coyote feed perhaps?

[PureCountry]

I'm not sure what the "level" of heredity is for longevity or fertility, according to your American AI Manual, but I think they're the 2 most important traits to select for. Of course I'm not going to keep a heifer that's built like a goat just b/c her momma lived to be 19, but I don't even look at a well put-up heifer if her pedigree is full of cows who came in open and/or were culled at an early age.

As for proving which traits are more inheritable(??) than others, I've seen different studies with different results. I find it hard to believe that studies can prove these things. Think of the numbers required to prove that type of consistency, or lack thereof.

[cswilson]

Yeah grassfarmer I make sure my A'I customers use the wrong bull for their situation-works every time. I've been our companies top guy in Canada a couple times and I only market maybe 4 or 5 of the bulls in the catalogue. I find most customers respect you more if you are upfront with them if you don't agree with their choice of bulls. I'm pretty lucky I get to deal with some pretty astute commercial men-a few purebred ones too lol. Most purebred breeders who hate the big A'I units are usually pimping semen on their own bulls too which is fine -competition never hurt anyone.

[cowman]

Pure country: I'm not trying to be argumentative here but the fact is a pedigree with a lot of long lived producing anscestors might mean something...or it might not?
Who knows under what conditions those cows/bulls were raised? Probably not like you might be raising them? And who knows if they had a calf every year or were regular as clockwork with their calves?
Now maybe you have a breed that puts some serious emphasis on these traits but I will tell you all breeds don't! One of the premier lines in the Canadian Hereford breed comes from a cow that had two calves in twelve years! Now mind you those two calves were worth probably more than 100 calves in a monetary sense, but who in commercial production could afford to keep a cow like that?
I think, in commercial production, a cow needs to bring home a calf every year... no matter what. If she doesn't skid her and bring in someone who will.
Since BSE hit we've sold one cow who wasn't in calf. We've had cows who had late calves that probably should have gone but didn't because the price was a joke.
I actually don't get all bent out of shape because a cow might be late one year. She usually catches up in a couple of years anyway? I always figure it doesn't matter when a calf is born anyway...but when you sell him?

[smcgrath76]

heritability or the amount of observed variation that can be explained by the genetic component.
Generally low for fertility traits. Around 0.01 to 0.20 depending on the trait and how it is measured.
In terms of longevity, there are several ways to describe longevity for genetic analysis. The most common is stayability (if a cow has a calf and is still in the herd at 6 she gets a 1) heritability of this ranges around 0.1 to 0.25.
Another way to look at it is number of calves by opportunities to calve. Heritability is generally lower than stayability.

Basically these traits are slower (harder?) to change than traits like growth, carcass and temperament that have moderate to high heritabilities.

As well, heritability may differ depending on the breed and whether the data is from a tropical or temperate environment. All heritability tells us is how much difference we can explain through genetics. As we gain more knowledge of genetics (better models, gene markers, etc) these values may be increased. It is pretty common for a breed to reevaluate their heritability esitmates every so often, and it is one of the first steps done when developing new trait evaluations. heritability also depends on how a trait is defined. For example the heritability of marbling is different when calculated on a carcass weight endpoint, versus and age endpoint, versus a fat endpoint.
Often hard to measure traits have a low heritability just because it is hard to get good data/information on them, and/or because there are a lot of other factors involved.

There are some pretty neat non-standard evaluations including:
stayability/longevity - takes a long time measure and to change
heifer pregnancy
docility
tenderness
days to calving
Mature size/maintenance energy
Net/residual feed intake