Colostrum Management and Monitoring IgG Levels

Good Morning,

Today, I am going to go through how to check the bloods for pass/fail, and what to do if you are getting multiple failure of passive transfers.


  • Refractometer
  • Tube of clotted blood and serum
  • Paper towel
  • Good lighting

Process (with an ocular refractometer)

  1. Put paper towel down on the surface you are going to be working on and set the refractometer on top. Sometimes, some blood or serum might leak off the bottom and makes a mess.
  2. Open the top of the refractometer and the top of the blood tube. Be careful not to shake up the tube, it will sometimes cause the blood to recombine and it will be more difficult to read.
  3. Pour a generous amount of serum (clear liquid) onto the glass plate and close the lid. I lightly press down to evenly distribute the serum on the glass.
  4. Hold the refractometer up to your eye and look through the lens. There should be a clear line (half blue, half pink) that will meet on the scale to give you your reading.
  5. Make sure the lighting is good. If it is not, you will have a hard time getting a clear reading.
  6. If you accidently shake up the tube too much (like I did in the photos) the line will be fuzzy. As long as the minimum (5.5 g/dL) is covered in pink coloring, and below 8 g/dL, I would call that the “safe zone”, if you can’t get a sharp line for some reason (shaking the tube, waiting too many days, etc.).

At our farm, we consider passing 6.0 g/dL or 9% Brix. Anything below that we consider a fail. The industry standard for failure of passive transfer is less than 5.5 g/dL or 8.4% Brix. We also have had it where the reading is too HIGH. This can mean that the calf is dehydrated, causing the IgG to be more concentrated (less blood volume). If IgG’s are continually too high, you need to consider looking into maternity pen cleanliness.

If you are continually getting failure of passive transfers, you need to take a step back and investigate your maternity pen and colostrum management.

Things that can cause failure of passive transfer:

  1. Quality – low quality colostrum (less than 22) can be an issue because there aren’t enough IgG to go around. Calves need at least 50 g/L of IgG in their system to be successful.
  2. Quickly – Calves gut is WIDE OPEN when they are born. This can be a blessing and a curse. When a calf is born, the gut has to be open to allow the very large antibodies to get into the system. A calf needs to get colostrum within four hours of birth to be the most effective. After 12 hours, the gut is substantially more restricted, and after 24 hours, the gut is almost completely closed. Feeding colostrum (or “transition” milk) after 24 hours has been shown to have other benefits, but it is usually cost and labor prohibitive to feed after the first two feedings.
  3. Quantity – It is recommended that calves receive 6 quarts of high-quality colostrum, split into two feeding (4 quarts and 2 quarts) or 3 feedings (2 quarts each).
  4. ******Clean! – My personal favorite. Colostrum needs to be free from pathogens and harmful bacteria. There are many reasons for this, but the main reason is bacteria in the colostrum equates to lower absorptive capability by the calf’s gut. Bacteria = low IgG levels in the blood. The best way to do this is via pasteurization, but even then, pasteurizing can only take care of a percentage of the bacteria load. Meaning, more bacteria in equals more bacteria out. Also, if your pasteurizer is malfunctioning, this can incubate bacteria, causing it to replicate extremely quickly.
    1. There is only so much room in the calf’s gut to absorb. If the bacteria are claiming that space, there will not be room for the IgG’s to get in there.
    1. Not only does the colostrum need to be clean, the entire birthing area needs to be clean also. A dirty maternity pen can cause you just as many issues and dirty colostrum.
    1. Make sure your equipment is clean. If you are questioning whether your equipment is clean, find someone with an ATP meter, and have them do a sanitation audit in your maternity pen.
  5. Calories – Colostrum contains a substantial number of calories to give the calf that first boost of energy after birth. Colostrum needs to be at least 100*F. Anything below that is too far below the calf’s body temperature, and it will require her to use additional calories to warm it up before digestion. This will also cause a delay in digestion!

As you can see, taking bloods and checking them for total proteins can tell you MANY things about your maternity pen program. This can be a great way to show what is working and what is not. It can be a great opportunity to find weak points in the system, and in return, it can help you improve you calf program greatly! You need to consider cleanliness (of colostrum and maternity area), quality, quantity, and how quickly you are getting the colostrum to the newborn calf. These things can all have a very large impact on calf success.

What do you think is the most important part of maternity pen management? Why?

If you need help checking total proteins, doing a sanitation audit on your maternity pen, or help looking into the management of your maternity pen employees, Message Us!

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