Now that we are well into fall, it is time for you decide which cows get to work for you another year. No different than an employee, your cows should have an annual job performance review. Reasons for termination of the employee include:

  1. Job performance (not weaning a calf)
  2. Respect for others (bad disposition/attitude)
  3. Inadequately equipped for the work (bad udder, teats, feet and legs)
  4. Work ethic (weaning a light-weight calf)

The first three should be a pass/fail decision. With “work ethic,” however, there is a continuum of performance allowing some latitude in deciding if she is working hard enough.

The basis for evaluation of the cow is calf weaning weight, which means being able to individually weigh the calf. According to producers I talk to who have purchased a scale, this is the most valuable tool on the farm. A $2,000 to $3,000 investment gives you the ability to collect and turn data into information used to make management decisions.

Weaning weight

To accurately evaluate cow performance, you need to measure the calf’s weight when the majority of its nutrition came from the cow. After weaning, a greater proportion of its lifetime diet is composed of ingredients other than milk. What you want to know is how much milk did this cow produce? Calf weight at weaning is the most practical method of making that determination.

Capturing a weight at weaning is good, but it doesn’t tell you the entire story. If you don’t account for calf gender and age along with the age of the dam, you may come to the wrong conclusion about her work ethic.

205-day weaning weight

The Beef Improvement Federation Guidelines ( state that weaning weights should be standardized to 205 days of age and a mature age-of-dam basis. Weaning weights should be taken when calves that have been raised together average about 205 days of age. Adjusted weaning weights should be calculated for calves within an age range of 160 to 250 days.

Younger calves generally weigh less, as do heifer calves. Young cows (more than 5 years) and older cows (\>10 years) also wean lighter calves. Account for this variation. To be clear, the 205-day weaning weight is not an indicator of profitability, nor is it intended to be. The purpose of calculating the 205-day weaning weight is to evaluate a cow’s milk production. The best indicator of profit is the weight of calves sold, which, on some farms, may be weaning weight.

On commercial farms the formula for calculating the 205-day weaning weight is:

(Wean wt. – Birth wt.) + Weaning age in days x 205 + Birth wt. + Age-of-dam Adj.

The age of dam adjustment is found in Table 1. If a 3-year-old cow has a bull, then 40 pounds is added to the 205-day weaning weight. If the cow is between 5 and 9 years old, no adjustment is made. (See Table 1).

Table 2 demonstrates the importance of making adjustments to select the right cows. Weaning weight of the 10 cows is sorted from heaviest to lightest. The next column shows the ranking. Moving to the column labeled “205 d,” weaning weights have been adjusted for age of the calf at weaning, with the rank from heaviest to lightest in the column to the right. Finally, in the column labeled “Adj205d,” the weaning weight has been adjusted for age at weaning and also sex of calf and cow age.

Cow #1168 was ranked No. 1 in all three measures; she obviously is no slouch and, assuming she respects others and is adequately equipped for the job, she gets another 12-month contract. Cow #U35 was No. 5 in weaning weight, yet ranked 10th and ninth in 205 d and Adj205d, respectively. She doesn’t show respect for others (very aggressive at calving), so she would be a candidate for termination. Finally, cow #677 is at the bottom for weaning weight, yet the other two measures put her in the top (third and fourth). If you were just evaluating her based on weaning weight alone, you might cancel her contract when she actually did a pretty good job. Therefore, all things being equal, evaluation of the cow should be based on adjusted 205-day weaning weight. (See Table 2).

Another calculation that is helpful in determining where that cow stands relative to her contemporaries, is calculating a ratio. The formula is straightforward and results are shown in Table 3:

The values are interpreted as Cow #1168’s calf weaned 13 percent greater than the average, while Cow #9121 weaned a calf 16 percent less than average. To keep your herd’s weaning weight moving forward, cows with a ratio less than 90 should be seriously considered for non-renewal.

Most probable producing ability (MPPA)

This calculation is more complex, but it allows a fair comparison among cows of different ages and with varying numbers of calf records. The bottom line is that MPPA attempts to identify cows that produce heavy weaning calves every year.

MPPA is computed by the following formula, with results shown in Table 4:

It’s not possible to calculate a MPPA for first-calf heifers. Second, this is a very small data set, so there is not a large spread in the values. However, some trends are evident. Cow #1168 with only two calves in her record was still in the top 50 percent. Cow #U135, even with five calves has the lowest MPPA. Cow #9121 has the same MPPA as cow #1167, but #1167 only has two calves in her record compared to #9121 with four calves, so it’s probably worth renewing her contract.

Finally, while the focus has been on milking ability of cows to produce heavy weaning weights, too much milk can result in cows that don’t breed back. If this happens, it doesn’t matter how high your weaning weights are if only 80 percent of your cows exposed to the bull produce a calf (See No. 1 in list of reasons for termination at beginning of this article). The goal should be to get rid of the poor performing employees and keep working on increasing the growth genetics of your bulls and replacement heifers.

For those who are savvy with spreadsheets, using the formulas previously mentioned can help you calculate values for your cow herd. Otherwise, do an Internet search for “calculating adjusted 205-day weights” and “calculating MPPA.” As always, feel free to contact me.

Deciding which cows will work for you to increase the profitability of your farm requires an annual evaluation of their work. Having good employees that are fun to be around is nice, but if they aren’t pulling their weight, there are other ways to spend your time.