BEEF HERD HEALTH

BY W. MARK HILTON, DVM

 Heifer development is a critical part of most beef cow-calf businesses. We hear the term “heifer development” frequently, but what does it mean? What are the goals? Do you want to get the maximum number of heifers bred or do you want to maximize their profit potential?

The “old” recommendation was to have heifers at 65 percent of mature body weight at breeding. This generally achieves the highest percentage of heifers bred. In this scenario, if your average mature cow weighs 1400#, your heifers need to weigh 910# at breeding.

More recent studies out of Nebraska showed that if heifers are at 58 percent of mature body weight – 812# at breeding – you may get slightly fewer heifers bred, but you increase profitability. If your beef business is truly a business, this may be a change that will pay dividends.

Heifers reach puberty when they have about 15-20 percent body fat so this begs the question, “Do you want heifers that are easy fleshing and attain puberty with a low-moderate energy diet or ones you must really feed aggressively so they will finally start cycling.” I listened to a podcast that featured Dr. Eric Bailey at the University of Missouri, and he said, “I want my heifers to get pregnant despite my management and not because of my subsidy (overfeeding her).”

Now I do not want anyone to think that nearly starving heifers is the way to make a profit. I always remember the quote, “You can’t starve the profit out of a business.” The same is true with replacement heifers. But you can spend so much on them that turning a profit is nearly impossible.

In the Nebraska study, the heifers that were bred at 58 percent of mature body weight cost about $50/head less to develop. When I work with producers that have either overfed their heifers or have very poor reproductive rates on heifers due to overfeeding early (more on this later), their first comment is, “But my heifers averaged 500# on weaning day (Oct. 15 for example) and I am not breeding until June 15 for a March 23 calf. How am I going to have my heifers gain only 312# in those 240 days? That is only 1.3#/day. My cattle are bred for growth.”

The solution in many cases is to graze the replacement heifers on corn crop residue for 60 days and then a low-quality forage for 30 days during fall and early winter. Ideally the crop residue grazing would start about 30 days after weaning. If the heifers gain nothing during those 90 days, you still have plenty of time to add weight before breeding.

If heifers are weaned Oct. 15 and backgrounded for 30 days to gain 1.5#/day, they will weigh 545# on Nov. 15. If they still weigh 545# on Feb. 15 after 90 days of “roughing it” and breeding is on June 15, that is 120 days to gain 267#. That requires a gain of only 2.2#/day. 

If you are reading this and you have trouble getting heifers bred because they are too thin, do not do as I have outlined and call your nutritionist, extension educator or herd health veterinarian to discuss why this is happening.

For those that had heifers weighing 900# or more at breeding last year, please keep reading!