Nope, that is not a typo. Brix refers to a Brix refractometer, not bricks as in bricks and mortar. Refractometers are these cool little tools that measure levels of substances in liquids. You may be familiar with the refractometers that we veterinarians use to measure urine specific gravity or blood proteins. You, or your veterinarian, may use one on your farm to measure total serum protein as a proxy for colostral IgG absorption in baby calves. A Brix refractometer is a little different in that it reads out in the Brix scale. One Brix unit is equal to one gram of sucrose per 100 grams of sample. If you have a winery, you probably use one of these to measure sugar content of your grapes. It turns out that you can use this handy tool to measure a couple of important things you feed to calves: total solids in milk and IgG in colostrum.
If you feed whole, pasteurized waste milk to your calves you might be using a Brix already to measure the solids in the milk. This is important because waste milk varies quite a bit in nutrient density. One reason for this may be water added during the clean up process. Typical milk measures about 13 percent total solids. However, you might be feeding milk that is 10, eight, or even five percent total solids, which means that you are feeding less nutrients and more water. Fortunately, most farms that feed waste milk probably feed large volumes to calves. It is typical to feed calves one gallon of milk twice daily to calves at a week of age or older. (People who feed milk replacer are often shocked to hear that calves will consume this much whole milk, but they will.) Thus, even if your milk is somewhat dilute, you are still feeding more calories than you would be with a typical milk replacer, for example. What you feed may be vary quite a lot from feeding to feeding, too, but again, this works because of the large volume fed; plus, calves seem to be able to adapt with changes of a couple of percent or more in total solids fed. Still, if you want to get the best gains you may want to measure the solids of the milk each feeding and add powder accordingly to achieve a total solids of around 10-12 percent. Note though, that when using the Brix for total solids in milk, one should add two percent to the reading to convert to total solids. So, for example, if the Brix reads 8 percent, the actual total solids are around 10 percent.
A lot of you do not feed pasteurized milk, so why is this tool useful for you? Well, it turns out that the Brix is really handy for approximating IgG in colostrum. Recent work (Bielman, 2010) has shown that the Brix reading correlates very well with colostral IgG. Everyone remembers that IgG is the main antibody found in colostrum, and is the antibody that is absorbed across the lining of the calf’s intestine into its bloodstream. Everyone also knows that colostral transfer of IgG is absolutely critical to maintain excellent calf health and growth, and that the amount of IgG fed is the main determinant of amount transferred to the calf.
For bovine colostrum, a Brix reading of 22 percent correlates well with 50 gm/liter of IgG. This is the generally accepted standard of adequate colostrum. This tool can very quickly tell you if the colostrum you have just collected is of adequate quality. You could use a hygrometer, or a colostrometer, which is just a hygrometer with a scale for measuring colostrum. They work fairly well, but the reading depends on the temperature of the colostrum. They are sometimes hard to read, and are really easy to break. You also have to clean them after each use. The Brix is easy because it automatically compensates for temperature, it only takes a drop of two of milk, and it is really easy to clean up. Best of all, most of the Brix refractometers are cheap. I just clicked over to eBay.com and I see one for $14.00. There is a digital version for $144. The advantage of the digital version is that it may be easier to read. However, in the recent paper by Bielman, the researches found the regular, optical version of the Brix to be easy to read, and it generated the same results as the digital version.
If you are going to buy a Brix, look for one that can read values from 0 to 50 or so. Some only read values much higher; these might be fine for making that fine cabernet, but will not work for milk or colostrum. Look also to make sure that it has ATC, or automatic temperature compensation. This ensures that it will compensate for different sample temperatures. If you buy the cheaper, optical version, it helps to stand under a bright light when reading the result, so don’t try to read it in that feed room with only one, fly-stained light bulb.
Get a Brix; give your calves that extra edge.
References available on request.
Jim Bennett is a dairy veterinarian at Northern Valley Dairy Production Medicine Center in Plainview, Minn. He and his wife, Pam, have four children. Jim can be reached at email@example.com with comments or questions.