“Culling should be based on economics—what is better for the current and long-term profitability of the herd and not on some predetermined benchmark of what culling should be,” says Mike Overton, a dairy analytics advisor with Elanco Animal Health.
“There are times when we have a heifer coming into the herd that is very valuable. That means that an older cow that is not sick, is not lame, needs to go because she is not producing to the potential you would expect,” says Overton.
“Other times, I have a heifer that is about to calve that I’m not really enthusiastic about an I probably should not calve her into my herd and pus hout a good, productive older cow,” he says.
What that basically means, he says, is that each culling decision should be a bit individualized. But it will also take data such as the heifer’s genetic background, health history and even rate of gain to determine her potential in first lactation.
A heifer’s milk producing potential and milk price will both determine the break-even milk production of older cows on the cull list. See table. For example, at $17/cwt milk and a heifer coming in at just 20,000 lb/year potential, the break-even milk for a cull cow candidate is about 45 lb/day. But if her potential is estimated to be 24,000 lb/year, the break-even milk production for the cull candidate jumps to 55 lb. The same dynamic occurs was milk prices rise and fall. See table.
Targeted Level of Break-even Milk For Culling
Milk Price Projected 305-day Milk for 1st Calf Heifer
20,000 22,000 24,000
$17 45 50 55
$18 49 55 61
$19 54 60 66
$20 58 65 71
“As I improve the quality of replacements going into the herd, the breakeven milk production of when to cull older cows also goes up,” says Overton.
But the reverse is true if you have low-potential heifers. Then the question becomes when should you cull those heifers rather than raise them through calving? The answer: The sooner the better if you are sure she will not perform well when she calves. Having genetic data and health data is critical to this decision, says Overton.
“Keeping the heifer longer results in greater losses unless you anticipate that you be able to capture more value as a heifer reaches the springing time period,” he says. “Right now, market conditions are not favorable [for keeping that heifer through calving], but we don’t know where that is heading in the future.”
For more on calculating the number of replacement heifers you need to maintain herd size, click here.