Cattle producers have done a tremendous job of increasing weaning weights over the last 30 to 40 years.  A 400 to 450 pound calf a weaning time used to be a good calf.  Now if one comes in this light, we are looking to cull the mother as quick as possible.  Today, 600 pound weaning weights are common and sometimes this figure is even low.  It is not uncommon to have calves wean off at 700 to 800 pounds.

This unbelievable increase in weaning weight has been made possible by several factors, including the introduction of the continental breeds, the use of EPD’s and selection pressure for growth.   The increase in weaning weight has brought with it an increase in mature cow size and an increase in feed requirements.  So how big are the cows these days? 

In an article written by Dr. Bryan McMurry who works for Cargill Animal Nutrition, which appeared in the December, 2008 Feedstuffs magazine, from 1975 to 2005, the average weight of our cows have increased substantially.  In 1975, the average weight of cull beef cows at slaughter with a body condition score of 5 was 1,047 compared to the average weight of 1,369 in 2005.  This is an increase of 322 pounds.

For many people, a 1,370 pound cow doesn’t seem too bad, and it probably isn’t, but the thing to keep in mind is this is the average size.  Half of the cows are bigger than 1,370 and half weigh less than 1,370.  Therefore, we have a large number of cows weighing 1,400 plus in this country.

Is this too big?  It depends, of course, on your feed resource and the size of the calves you are weaning off of these big cows.  A 1,400 pound cow weaning off a 700 pound calf is probably pretty efficient.  If she only weans off a 500 pound calf, she is a candidate for a free trip to town.

With tough economic times facing us in the cattle business, our cow herd must be efficient.  Monitor cow size and calf weaning weights.  Next time you purchase replacement bulls or heifers, be sure to check the data on residual feed intake, (RFI).  This will give you a good idea which bloodlines are efficient.  Also, try to keep the frame score of the cows in the moderate range, while not giving up weaning weight.  This will lower cow feed requirements while maintaining production.  A pretty good recipe for profit.