A dairy herd’s reproductive program is one area that often leads to large profit losses. This [article] takes a look at the economic considerations associated with reproduction.

One of the easiest ways to quickly assess the reproductive status of the herd is to look at the herd’s average days in milk (DIM) over the last 12 months. Use the 12-month average for evaluation, as seasonal differences in calving rates can alter considerably.

Benchmark levels published through Lancaster DHIA show the herds using their service have an average DIM value of about 193. This equates to a calving interval of about 14 months.

A commonly used formula exists to determine lost profits from a high DIM value, which results in longer lactations with lower average production.

When the herd’s 12-month average DIM value is greater than 200 days, a significant problem is indicated. It has been determined that for every day in milk over 160, 0.17 pounds of milk per cow per day is lost. These values came from a very large study, which compared milk production levels and DIM in producer herds.


Let’s calculate the economic impact for a milking herd of 100 cows, with an average DIM of 200. In this calculation (below), the milk price per hundredweight is assumed to be $15.50:

(200 DIM - 160 DIM) x 100 cows
x 0.17 lbs x $0.1550/lb
x 365 days per year
= $38,471 in lost milk revenue

I encourage producers to step through this calculation with their own herds. The information you need is readily available in your DHIA records. With the Lancaster DHIA average near this level, many of you may come up with similar numbers.

It has been my experience that the costs required to decrease these losses (e.g., drug costs for breeding programs, increased veterinary fees and other costs, including good vaccine protection) are far outweighed by the economic benefits to production and profitability.

Another benefit is the increased number of replacements that will result from the decreased calving interval. Herds that have been successful with good breeding management see increased heifer inventories. These additional animals can be used to replace poor producers or cows with chronic mastitis issues. They can also be easily marketed and can provide another source of revenue for the dairy.

Your herd veterinarian can help you with implementing reproductive programs to increase your profitability.

The benefits will not be realized overnight, as it will take at least one lactation to bring down the herd’s average, but I encourage you to be diligent and work on the problem if it exists. PD

References omitted due to space but are available upon request.

—From The Agri-Vator, Vol. 7, No. 4

Robert F. Guttroff, DVM, Big Valley Animal Hospital, Reedsville, Pennsylvania