Using a Colostrometer
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- [Woman] The concentration of IgG in colostrum varies widely from one cow to the next.
From less than 20 to over 100 milligrams per milliliter.
Colostrum containing 50 milligrams per milliliter or more of IgG is considered to be a high-quality feed for newborn calves, and most calves need to receive 150 to 200 grams of IgG to achieve successful tranfer of passive immunity.
Measuring IgG concentrations in colostrum can be very useful in managing colostrum quality and monitoring colostrum feeding practices.
We can't tell by looking at colostrum how much IgG it contains, but we can use some simple on-farm tools to separate high-quality colostrum from low-quality colostrum and improve passive transfer.
In this video, Sonia Gelsinger will demonstrate how to use the colostrometer to test colostrum quality.
- There's a couple different field tools we can use to measure coloctrum quality.
One of them is a colostrometer.
A colostrometer is a hydrometer that uses the correlation between colostrum density and IgG concentration to give us a measure of colostrum quality.
It has a scale on it that will relate the colostrum density to the IgG concentration and give you an exact value.
It also has a color coordinated scale with the green being high-quality colostrum and the red being a poor quality colostrum.
These come in multiple different models, but all of them will come with a colostrometer and a cylinder for measuring the colostrum quality.
To use this, you would mix up your colostrum well, especially if it's been sitting for a little while.
Pour the colostrum into the cylinder, filling it almost full but not quite.
And then you simply drop the colostometer into the colostrum inside the cylinder and wait until the colostromer stops moving.
Sometimes it will move up or down a little bit, and then you get your final reading once it stops.
Another thing to keep in mind as we're waiting for this is that the density of the colostrum is temperature dependent.
The colostrometer scale is calibrated to measure the colostrum and room temperature, but if it's higher temperature, like if you had just milked the cow and measure the colostrum quality or if it's lower temperature, like you just got it out of the freezer and it just thawed out, that's going to affect your measurement.
There's a spreadsheet available on the Penn State Dairy Extension website that will give you the accurate measure of colostrum as long as you measure the temperature of the colostrum at the same time as you measure the quality.
So, for this particular sample, you can see that it in the green, so it is a high-quality colostrum that you could then go and feed your calf.
If you want to exact value, you simply turn the colostrometer around and it'll give you the exact value on the scale.
This particular example is about 120 milligrams per mil of IgG.