Correlation between calf weight and cow longevity?

[cypressfarms]

In the never ending miriad of traits to select for, one trait, low birthweight is one that has been discussed and cussed many times. I've had some recent discussions with several knowledgable cattlemen that believe that cows that have lower birthweight calves will live longer than cows that have larger birthweight calves. Does anyone hold any credence to this "wives tale"?

Could it be possible that a side benefit (besides having less calving difficulty) of low birthweight calves is that the moma might be around to have a calf or two more than those that have big calves? Common sense says that a cow should be productive as long as they are able to forage effecively (a sound mouth), but I have to wonder if calf size has a longterm effect on fertility?

Anyone wanting to join in on this with facts or out and out lies on the subject? :lol:

 

[Workinonit Farm]

Well, I'll join in....for now. I have no facts or lies, only observations and theories.

I agree that it makes sense that as long as a cow can forage effectlively, she should remain somewhat productive. Eventually though she's going to wear out.

I don't think that calf size has a big effect of longevity. Many cows have been fertile for up to 15 years or more with a history of 80lb-plus calves.

I think cow management and genetics have more to do with longevity than calf size. Unless of course you have a cow who gives birth to some freak-monster sized calf and it trashes her repro system then obviously the size of that calf had an effect on her longevity as a brood cow.

Katherine

 

[Angus Cowman]

Well, I'll join in....for now. I have no facts or lies, only observations and theories.

I agree that it makes sense that as long as a cow can forage effectlively, she should remain somewhat productive. Eventually though she's going to wear out.

I don't think that calf size has a big effect of longevity. Many cows have been fertile for up to 15 years or more with a history of 80lb-plus calves.

I think cow management and genetics have more to do with longevity than calf size. Unless of course you have a cow who gives birth to some freak-monster sized calf and it trashes her repro system then obviously the size of that calf had an effect on her longevity as a brood cow.

Katherine

I agree with Katherine because I can't think of a better response or a better lie to add at this time but I will keep pondering on this and if I come up with a better explanation or a longer lie I will let ya know

 

[LoveMoo11]

I don't think there is a correlation. A cow may not even have problems having a bigger calf. If she does and gets injured or sick as a result, then yes, there would be a correlation, but that would also be the fault of the cow's physiology, not just the size of the calf. When we had a dairy our holsteins had 100lb calves, no problem and lived 12-15 years.

 

[regolith]

I don't know about calvings in the beef world, but I know for sure that the group of dairy heifers bred to a low birthweight bull are going to live on average much much longer than the group of heifers bred to a high birthweight bull.

A large number of the heifers bred to an over-sized bull won't get back in calf (not sure of the exact stats, but I've assisted up to 40% of calvings in groups like these, and I think about half the assisted heifers get back in calf no problem and half become repeat breeders - the repeat breeders are very likely to be culled as two or three year olds).

Once they're three years old, I shouldn't imagine it makes much difference unless the birthweight is extreme. And the consequence of repeat breeding is exacerbated in a seasonal calving system - if my cows don't get in calf within three cycles they're out, and if they're late calvers and they don't get in calf in one or two cycles they're out. Late calvers stay late calvers unless they're very fertile.

I'll throw out one other speculation. Older cows may be more susceptible to calving difficulty. I breed mine (older than 10) as for heifers, just in case.

 

[regolith]

And I've just been locally contradicted re heifer dystocia related to poor breeding: http://www.agridata.co.nz/blog/2009/01/ ... /#more-616

I should look and see if I've got some actual stats among my own records about rebreeding.

 

[Jeanne - Simme Valley]

But, I think that article is a little misleading. All the articles I have read basicly say EARLY assisted heifers have the same results as non-assisted.
You can't compare a heifer that has struggled for a long time and THAN got assistance. It has been proven that she will take longer to breed back & the calf has a lower survival rate. And the same is true for a HARD calving - earlier assistance is better, but they still will probably have problems.

 

[cypressfarms]

Two breeds that quickly come to mind are:

Brahman and Longhorn.

Both of them are known for their longevity, and both are know for small calves.

 

[brandonm_13]

It's not really as much the size of the calf as it is the difficulty in calving. Lots of holsteins can pop out big calves, but that's not as big of a deal because they are larger too. It depends on the size of the calf relative to the size of the cow. Shape of pelvis, shoulders on the calf, how the calf is turned, how fat or thin the cow is, all can be variables that go into how easy/difficult calving is. And difficult calving causes stress. Stress lowers the effectiveness of the immune function, which affects how easy or hard it is for a cow to get diseases. Some diseases can kill a cow. Some cause only small problems, and some "cured" diseases never really seem to go away, and seem to pop back up later on in life. Each of those can affect how long a cow is productive.