Why check colostrum quality?

Checking colostrum quality is not a new idea, in fact, for more than 30 years it has been a standard recommendation. So what’s new about it or why bring it up again?

It’s well known that the quality of colostrum, as defined by the concentration of antibodies, or Immunoglobulins (Ig), varies quite a bit. Research as well as on-farm experience tell us that regularly. Although the number of dairy producers who check quality keeps increasing, there is still much room for improvement. The 2014 USDA Dairy NAHMS (National Animal Health Monitoring System) study showed the use of quality monitoring by herd size:

Percent of dairy operations that check colostrum quality by method and size of farm


(30-99 cows)

Medium (100-499 cows)

Large (500 or more cows)





Brix refractometer




Large farms check colostrum quality far more than small or medium farms even though the cost of the tool is very low relative to the benefit and is accessible to all farms regardless of size. According to the USDA NAHMS report, the Brix refractometer is the most accurate method for measuring colostral IgG of the on-farm methods currently available.

Why test colostrum quality? Here are some reasons to consider:

1. It’s not all good.

Using a Brix refractometer, a reading of 22 corresponds to approximately 50 mg/L of IgG, the minimum standard for high quality colostrum. However, much colostrum fails to meet that standard. A nationwide evaluation of quality and composition of colostrum on dairy farms in the U.S. (Morrill et. al. 2012) showed almost 30 percent of colostrum tested failed to meet the minimum standard. Thus, almost a third of colostrum was not acceptable for first feeding (lower quality colostrum can be used for subsequent feedings).

2. Concentration X volume = amount.

It’s only about concentration because we feed a limited amount of colostrum. If the goal is to provide 180 - 200 grams of IgG to the calf within six hours of birth, and if we are feeding colostrum with 50 mg/mL of IgG, then it will take approximately 3.75 liters (four quarts) to get that amount into the calf. But if the concentration is only 40 mg/mL it will take approximately five quarts, and very few calves get that amount.

3. You may be discounting heifer colostrum needlessly.

Some producers don’t use colostrum from first calf heifers because of the common perception that it’s of lower quality. That perception has been based on past experience and even research on the colostrum quality from first calf heifers.

Rejecting all colostrum from heifers means producers need to replace the colostrum for approximately 40 percent of the calves born on the farm. However, improved vaccination programs for heifers have resulted in higher quality colostrum from this group. The results may be farm-specific, but testing on many farms has shown that much of the colostrum from first calf heifers meets the standard. Deciding not to use heifer colostrum for first feeding without testing is wasteful. It fails to use a resource when the quality is good.

Michigan State University Extension conducted a brief survey of dairy producers about colostrum practices in January 2017. Thirty-eight producers responded to the survey and though they are not considered a random sample, their responses are valuable. Of those who responded, 16 percent rejected first calf heifer colostrum outright, but among those who tested quality, 90 percent (19) used colostrum from heifers as long as it met their standard.

4. You will be able to tell when quality changes.

Things are continually changing on the farm: Feed quality, group density, weather, timing of practices, etc. Some changes may affect the quality of colostrum. By checking quality, you will enable you to detect when quality is changing. Change in quality can be an indicator that procedural draft has occurred or other fundamental changes have happened. One producer wrote on the survey: “If I start to see a lack of good quality colostrum, my first place to look is at . . .” The point is that only by checking quality does he know when that occurs and it prompts him to check other things.

5. You can learn what impacts quality.

There are still unknowns about all that may affect quality, but as you check quality routinely, you will learn about the associations that are true for your farm. In response to the survey, one producer wrote: “I’ve noticed there is a direct correlation between . . . and colostrum quality.” The key is to learn on your farm what things correlate to higher quality colostrum and to change your programs to ensure cows provide the highest quality of which they are capable.

Colostrum quality is the first step in making sure your calves are protected and set-up for success in life. Their success means your success. Let’s make colostrum quality measurement routine on every farm.

Did you find this article useful?