Cow efficiency is a hot topic, especially in areas of limited resources. Some feed and forage producers assume that a small cow is a model of efficiency but there's much more to it than that. Some cows seem to maintain fleshing ability while producing at adequate levels in our herds. So we can select heifers from these cows but a recent trend has me concerned.
My concern is that we keep selecting bulls which will produce heavier milking heifers. In the Angus breed, for example, we are using bulls that have milk EPDs of over 40 (and still climbing) for goodness sakes! How much milk production do you need to get weaning weights where you want them? How much milk production will your forage/feeding program support? How much feed do you want to buy? Increasing milk production comes at a nutritional cost which, if not met, will severely impact reproductive performance. The following chart shows the effect of milk production (actual, not EPD values) and body size on energy requirement of beef cows two months postcalving. The increase from 10 to 30 lbs of actual daily milk production requires an additional 5.5 lb of TDN. That would be about an additional 11 lb of hay or 5 lb grain daily to maintain body conditions and production. Increases in body weight are significant, too, but not so dramatic as increasing milk production. I suppose that's why we don't use Holsteins in our beef herds . . . . . yet.
Seedstock producers should be focused on meeting the needs of their customer's cow herds - not just focused on big numbers. Bigger isn't necessarily better for EPDs. Cow-calf operators also have the responsibility to educate themselves on what they really need. They should look at their cow herd and decide what deficiencies they need to correct or improve and work on these areas.
If you want to increase weaning weights in your commercial herd, you might simply consider crossbreeding as an alternative to putting more milking ability into straight-bred cows. That might be a more sustainable option in the long term.
Anyway, what matters most is that your breeding and feeding program works on your farm! Here's a simple test - look at your 2-year-olds when they wean a calf. If they wean a good-sized calf, are bred back early in the breeding season and have maintained good body condition, then your breeding (milk and growth) and feeding/forage programs are pretty well matched up. Don't let big numbers "steer" you away from profitability.
Source: Dr. Roy Burris, Beef Extension Specialist, University of Kentucky