More pounds of production. That’s the goal many producers, like you, seek so they can ultimately sell heavier calves. One way to reach this goal is to raise larger cows. However, there can be some impacts from increased cow size that could hurt your herd’s performance.
We can infer the average cow size is increasing based on the yearly rise of fed cattle carcass weight nationally. Similarly, U.S. Meat Animal Research Center evaluations of EPDs across multiple breeds also show increased weaning and carcass weights for more than 40 years.
The perfect average cow size depends on the unique needs of your farm or ranch based on the environment and available feed resources. For example, a 1,500-lb. cow might work well in the Midwest, where there are lots of feed resources. However, that same cow might not be as profitable in the West where she has to travel farther for feed and water.
Feeding for efficiency
Bigger cows have higher nutritional requirements. They need more energy, protein, vitamins and minerals as they get larger to maintain themselves and optimize performance. The good news is cows get slightly more efficient per pound as they get bigger. If you compare a 1,500-lb. cow to a 1,000-lb. cow, she would be 50% larger in weight, but her energy requirements would only be 36% greater than those of a 1,000-lb. cow.
The efficiency of larger cows does come with a drawback regarding their calves. Typically, there isn’t a proportional increase in calf weaning weight as cow size rises. A 2009 North Dakota State University study shows the weaning weight ratio decreases as cows get heavier. In the study, a 1,000-lb. cow weans 48.5% of her body weight compared with only 43.6% of body weight weaned for a 1,400-lb. cow.
A major nutritional impact of larger cows is the effect on pasture stocking rates. The traditional stocking rate is based on an average cow size of
1,000 lb. If your stocking rate hasn’t adjusted to current cow weights, your cows could be shorted on nutrition, which affects performance, such as weaning weights and pregnancy rate.
You could also run into issues where the pasture won’t last for the whole grazing season, so you might need to purchase more forage or find other pastures. An efficient way to supplement cows on pastures is by offering free-choice, self-fed options such as tubs, blocks or liquid feed.
To further dial in feeding, you can hand-feed supplements such as cubes or a mixed ration. However, accurate measurement of how much your cows weigh is essential to hand-feed effectively.
Do you own scales?
You’ve probably made genetic changes to your cowherd, and average cow size has adjusted. Having a baseline of what your herd weighs will help make better management decisions, such as stocking rates and how much to feed.
It’s hard to tell exactly what a cow weighs by looking at her, so it’s important to get an accurate weight for your cows at least once per year and be consistent with it. Weaning is an ideal time to take this measurement since you’ll likely be making culling decisions, and you can pinpoint larger cows that don’t fit your operation.
If you have a set of scales at your working facilities, that is a good start. For those who don’t own scales, it’s a great time to reinvest in your facilities. Digital scales under a chute are an effective option to accurately and efficiently take individual weights. Another alternative is a portable scale you can move in front of the chute or alley.
If you haul your cows to a pasture, consider weighing your herd on the trailer at truck scales. This is an easy way to get an average for the whole herd without adding too much additional work.
One other option is to look at how much your cull cows weigh on the sale bill each year. This approach won’t give you as accurate of a number as the other approaches, but it is a start.
There’s not a one-size-fits-all answer to addressing cow size; it’s dependent on your situation and what you can make work for your herd. Work with your nutritionist to start the conversation about the optimal cow size for your herd and to create a feeding and grazing program that fits your needs.
