optimum cow size

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oakview

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A frequently discussed, and sometimes heated debate on this site is optimum cow size.  Check out the 5-23-20 issue of Iowa Farmer Today for an interesting piece on the subject.  According to Kansas State Research and Extension beef specialist Bob Weaber, "Our results showed that in eastern Kansas, a 1,300 to 1,400 pound cow was optimum in that she was able to produce a moderate to high level of milk in an environment where all her nutritional requirements were met."  There was some dialog on the effects of increasing cow size and the amount of beef produced per acre.  The article pointed out several times that there was no one size fits all in regards to cow size.  The study listed 7 main factors to consider.  Interesting reading.  My interpretation is that if it works for you, go for it. 
 

aj

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Good utube. At least it is a new way of measuring things. I think a more moderate cow is better. Pounds weaned per acre is better than pounds weaned per cow. Extra milk might be a bigger factor. It depends on environment. This is a topic well worth looking into.
 

trevorgreycattleco

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Optimum cow size is like asking people who’s better Jordan or LeBron. You’ll get all sorts of opinions. I think the reality is you get your cows small enough but not too small to raise whopper calves on your available forage. It’s a dance. A 1300-1500 pound cow in Ohio will roll on with some hay in winter. Is she optimal in Kansas? I don’t know. Come fall the cows with calves half the size of them stay and those that don’t, don’t.
 

aj

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To me the question is how much more does a big cow eat than a smaller one? Can a smaller cow get by with less supplementation? It all boils down to is a smaller cow cheaper to maintain and get breed. To start with.....how many cow guys balance the number of cows per pasture right anyway? Years are different. I usually figure 1 pair to seven acres. That is sometimes to low and sometimes to high. Flexibility is almost more important to profit than cow size. The only way I see a producer who runs a certain amount of cows per acre is weaning time. You could turn out the usual number of cows per acre.......and then if it is a wet year you would leave calves on longer. If it is a dry year you simply wean at a earlier date.
 

GoWyo

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Here in SE Wyoming we are 100% rangeland grazing on native range with a couple of areas of domestic grass seedings.  I figure it takes 2.5-3.0 acres per cow per month (animal unit month or AUM) depending on the pasture.  We have about 12 pastures and try to stock them so that the pastures last 1-1½ months with about 3" of stubble remaining then move to the next.  This seems to provide enough cover for the range and cows have to spend too much time hunting for feed if we graze it any shorter.  By managing pastures this way, I have cows from 1100 lbs. to 1500+ lbs. that will maintain their weight and the calves wean off pretty close to 50% of the cow weight.  Any cow that raises a dink is on the cull list.  I am sure some of the smaller end cows can eat as much as some of the larger end cows, but there really is no way to measure it.  I am betting that in 5 more years the average weight is probably going to converge in the 1300-1400 lb. cow average.  Since we calve in March, we do feed about a half ration of alfalfa until May when the grass comes on.  No cow gets special treatment -- they all run together.

Raising Angus seedstock, the bull buyers in this area can talk moderate cow size all they want, but when they buy bulls, they won't buy the small frame end of the bulls because they want the weaning weights.  The 1300-1400 lb. cows tend to balance the productivity and efficiency on average under range conditions while producing marketable bulls.  Marketable bulls is where the profit lies.  Their sisters become replacements, so we have to watch our mature size and resist keeping the heifers with big weaning weights unless we are sure they will have a reasonable mature size.  Everything else basically meets their expenses unless we add value by feeding out steers and heifers for freezer beef.  Feeding puds isn't very profitable, so the cow base has to have some performance no matter their size.
 

shortybreeder

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aj said:
To me the question is how much more does a big cow eat than a smaller one? Can a smaller cow get by with less supplementation? It all boils down to is a smaller cow cheaper to maintain and get breed. To start with.....how many cow guys balance the number of cows per pasture right anyway? Years are different. I usually figure 1 pair to seven acres. That is sometimes to low and sometimes to high. Flexibility is almost more important to profit than cow size. The only way I see a producer who runs a certain amount of cows per acre is weaning time. You could turn out the usual number of cows per acre.......and then if it is a wet year you would leave calves on longer. If it is a dry year you simply wean at a earlier date.
This is why we run our core cowherd and then bring in custom-grazing cattle for the months of really high grass growth--if things go dry then we only have to wait 14 days to cut our numbers. If it turns into a wet year we can always call around to bring in a few more animals.
Plus it gets you paid upfront on the pasture acreage (rather than investing in the extra cows for 12 months) and reduces winter feed/labor requirements. I'd highly recommend the system to any seedstock producers trying to add flexibility to their system.
 

RyanChandler

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aj said:
Pounds weaned per acre is better than pounds weaned per cow.

You're 100% correct.  Worth noting how EVERY outfit that subscribes to this accounting have all come to a vastly different conclusion than the big ag funded research universities.  Of course those whose employment is contingent on cattleman purchasing inputs have an incentive to increase mature cow weights.  Feed salesman, nutritionist, reproduction specialists, machinery manufacturers, upteen consultants, on and on-- the livelihoods of all these people is dependent on cattleman selecting cattle that are unsuited for their environment.  These people have little to no role in my chosen model so of course they're going to intrinsically be opposed and spend as much research money as they can promoting ideas that prioritize their income over others.
 
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