IgG’s and Serum Total Proteins, Are they telling you a true story?
One thing that has been a main topic of concern and reference point for maternity pen success has been colostrum quality and subsequently a calf’s STP (serum total protein). While these are both great tools for your calf toolbox, be sure to take into consideration the whole picture, and not just one or two data points. Take the time to really think about what those two numbers are telling you.
The new gold standard for STP blood levels above a 6.0 g/dL or 9.0% Brix. If you are achieving those benchmarks, that is amazing! Be aware though, that doesn’t automatically set your calf up for success down the road.
Like stated above, colostrum quality and STPs are just a tool, and tools have their limitations. Some of those limitations may cloud your vision on if success is being achieved in your maternity pen or not.
Below, we are going to go through some limitations of IgG and STP testing.
IgG available does not equal IgGs absorbed. One way to look at IgGs in colostrum is the POTENTIAL. You might have the potential to play in the NFL, but if you hurt your arm in practice, that potential decreases significantly, the same is true for IgG absorption. Just because you fed your newborn calf 4L of colostrum at 25% Brix, doesn’t automatically mean she got her 200g of IgG (minimum) that she needs to achieve passive transfer. There are many things that can go wrong between putting that drop of colostrum on the refractometer, and the IgGs passing through the calf’s open gut. What might be something that would damper that potential?
High bacteria colostrum
Dirty feeding equipment
Wet or dirty bedding in the calving pen or calf holding area
Dirty calf warmer
Using dirty hands or clothing to handle newborn calves
Not getting colostrum to the calf quickly enough (within the first 6 hours after birth)
High disease pressure in the herd (e.i. Salmonella, mycoplasma, etc.)
2. Not all immunoglobulins are created equal! When it comes to colostrum, quality on the refractometer will tell you a lot, but it will also leave out some key factors like what kind of antibodies your calf is getting. That might seem like a crazy thing to think about, but it’s important to consider, how were you dry cows vaccinated? Was it done on time so that the cow or heifer could take that vaccine protection and put it into her colostrum? Are you giving the right vaccines to properly protect your calves from disease challenges you have on your farm?
3. STP need to be taken in a timely manner, but they also need to be taken in a strategic manner. You likely know that you need to pull blood between 2-7 days of age to get the most accurate reading of STP, but did you also know scours can impact that number too? Say you are pulling bloods on day 3, perfect, they are all coming back passing with flying colors! But what if the calf is scouring? Say she is, and it’s fairly severe, that will decrease her blood volume, and in return, increase the concentration of IgG in the sample. Why is that bad? I have seen dehydrated calves score as high as 9.0 g/dL, that is a clear indication of dehydration, but what if they’re all “normal”? A dehydrated calf vs. a hydrated calf can have a difference of a whole point. That means your 6.0 dehydrated calf could actually be a 5.0 failed calf hiding under your radar.
4. Consider how you are going to use that information to improve protocols and processes. Don’t go around poking calves if the data is going to sit in a computer or on a piece of notebook paper and do nothing. If your response to failed STP levels is, “these calves failed so I’m going to go give them antibiotics”, don’t bother pulling the bloods!
5. People like to consider STP a “proactive” instead of “reactive” management style, but I just disagree, because guess what? You don’t get to go back and try to give colostrum again, you get 12 hours to hit the nail on the head, if it gets missed, that’s it. That calf’s entire life is in your hands, don’t let a failed STP be the first step you take in being proactive. I am a firm believer in using STP as a first step to troubleshooting, but much beyond that, I would ask myself, why am I doing this? The only time I would consider STP on most calves a great idea is for insurance if you are raising calves for someone else.
Lastly, consider that you might be doing damage to your colostrum during processing (pasteurizing or thawing). Colostrum is valuable and delicate. One bucket of water that’s too hot can do unrepairable damage to IgG’s. One way to we have mitigated this risk is by investing in a coloQuick colostrum warmer. I takes a 1 gallon (4L) bag from frozen to ready to feed in 20 minutes, with no worries of damaged colostrum because of the even distribution of low temperature (110F) water, the machine spins, mixing the frozen and thawed colostrum!
These are just a handful of things to consider when looking at the data you are collecting, to make sure you are looking at the whole picture and not just assuming that because of this, this is also true, because under almost all circumstances, it’s not that easy. We wish it was!
If you are looking to upgrade your colostrum management system and make sure those valuable IgG’s make it into your calf’s system, follow the link below to see our line of colostrum management products.
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