The author is a partner in Maria Stein Animal Clinic, Maria Stein, Ohio.

We were halfway through reproductive exams when Henry told me that they had sold a load of cull cows last week that averaged 1,900 pounds and that brought in over $1,100 each. At first, this seems very lucrative for the dairy. Or was it lucrative? Obviously, these are the kind of culls you like to sell. The fat, open cows that have been productive and now aren't. The kind one client refers to as "jelly roll donuts."

Jerseys in field

Are any of these Jerseys "Jelly Roll Donuts" - cows that are open and putting on weight? Find those cows early along with the attack cows, and label them DNB (Do Not Breed). This way, investment in breeding culls is saved.

  • But would it have been better to sell them three weeks earlier at 1,850 pounds?
  • How much milk were they giving to offset their feed costs?
  • How much weight do cows like this gain per day?
  • Do these kinds of cows reach a point where they no longer gain weight or at least are less efficient gaining it?
  • What is the feed cost per pound of gain?
  • What was the opportunity cost of having that stall occupied by a more productive animal?

Like most questions in the dairy industry, the answer begins with "it depends." If I'm Henry's consulting veterinarian, then it is my responsibility to lead a discussion that helps Henry create a system to manage culls or understand the system that currently is being used.

A cull management system may be best described by what it is not. It is not, "Boy, it looks like we have a bunch of fat cows that aren't milking. Maybe we should check to see if they are pregnant and how much they are milking. We might have some to sell."

Declare them early
Dairies that best manage their culls learned to declare some cows as future culls early in lactation. This way, the investment in breeding them is saved and their chance of getting kept because they became pregnant is eliminated.

This makes the proportion of those herds considered "Do Not Breed (DNB)" higher than the average of 6 percent. Cows that should be added to this list include those with udders that are difficult to milk properly and those with truly dangerous dispositions. From what pen walkers tell me about heat detection, attack cows exist on many dairies.

There really is no reason for evil cows to stay. The $400 profit that individual cow will generate this year is not worth the workman's comp claim that she may generate.
Our DNB group also includes cows with chronic high somatic cell counts, recurrent clinical mastitis, or cultured positive for Staph. aureus and being managed by contagious containment methods. The system makes these cows DNB whenever culture or somatic cell counts are generated.

A system to track repeated incidences of clinical mastitis is easy with computer dairy management systems that track individual cow health data. When updating the "cowpage" with a new case, it is easy to count the number of clinical cases this lactation and decide "That is enough, we're not going to breed her anymore."

Feet and legs and uterine adhesions are the next reason to become a DNB. Hoof trimmers can make recommendations of which cows they cannot fix because the issue is skeletal or compromised beyond repair.

Uterine adhesions are diagnosed at postpartum exams or at first pregnancy exam. Sometimes breeders will ask us to examine cows because they don't feel right. Fortunately, we see less of these as calving and postpartum management has improved. Some treatments do more harm than good, and we are glad to see them used less frequently.

There is another group of cows that become DNB late in lactation. These are cows that have been bred a number of times without success. They still are profitable enough to milk for awhile but won't be in a few months. This is when most dairies make DNBs which will be a small portion of the herd.

So, now our herd has four groups of cows:
  • fresh cows
  • cows that we are trying to breed
  • cows that are pregnant
  • DNBs
Deciding when DNBs go on the truck has the potential to make or lose income. Dairies that have a computer management program that calculates a cow value should always sell the DNBs when the cow value is at or below the cull price for that cow even if that sale creates an empty stall.

Don't overstay welcome
We now are in unusual times where the market price for culls is much higher than usual. Miss DNB should go sooner if the barn is overcrowded or a replacement is readily available. If you do not have a cow value program, the method that Henry now uses requires knowing his feed cost per day for late-lactation cows is $6.15. At $22 per hundredweight of milk, DNB cows have to give at least 28 pounds of milk to cover feed costs.

Does some of that feed cost come back as gain if she stays longer? Yes, but only if she is not in heavy condition already and healthy enough to gain. Lame cows don't gain weight.

Is feed cost the only variable cost? No, it probably is only a little more than half of the cost of maintaining a cow. When it comes to continuing the career of a DNB cow with no future for high profit versus a replacement that has that potential, Henry has decided to put DNBs on the trailer when they reach production levels of double their feed costs.

Cows with risky health issues go sooner, and cows that have the potential to gain weight efficiently stay around until they get down to 40 pounds.

What is your system of managing culls? How is it working? If milk price drops and cull cows stay high, how will you adjust it? How does replacement availability or price affect it? If milk price stays steady but culls drop, how does it affect our strategy? Let's get our calculators out and have that discussion.

This article appears in the January 25, 2012 issue of Hoard's Dairyman on page 50.