Ask the Vet

Brood Cow Size

Have today's brood cows gotten too big? (Photo from Thinkstock/istock)

QUESTION: Is there an optimal size for brood cows?

I think many producers have unknowingly allowed their cows to get too large for their production systems. By focusing on weaning weights in their calves and using the cheap supplements of the recent past, they have selected for more growth in the heifers they retain.

ANSWER: I was always taught a cow should wean about 50% of its body weight. Calves with adjusted weaning weights of 550 to 650 pounds work well in our stocker and feedlot system and on the rail. So if we do the math that puts the ideal cow at 1,100 to 1,300 pounds. If it were only that simple.

Some producers, especially those in the grass-fed niche, feel cows that weigh less than 1,000 pounds work best. And I have several very good producers whose cows average between 1,400 and 1,500 pounds. So one size does not fit all.

What is the take-home message? Weigh your cows and calves, collect data and do the math. Never assume your largest calves are the most profitable. At today's input and calf prices, a 1,500-pound cow would have to wean at least 50 and possibly up to 100 pounds more calf than a 1,200-pound cow to recover the higher carrying cost.