T17.118 From Science Class to Calf Feeding: How using a Brix Refractometer Creates Consistency Remember experimenng with prisms in middle school science class, casng rainbows all over the classroom? Those fun tools, which separate different wavelengths of light, are the main components of refractometers. Veterinarians have been using Brix refractometers for many years to assess concentraons of liquids like blood serum and urine. Others use refractometers as a quality-control tool for processing liquids such as wine, beer, maple syrup, honey and apple cider. Now, this convenient, hand-held tool is being adopted widely by calf raisers to improve consistency of colostrum and waste milk. Refractometers work by measuring the degree of bending of light through a liquid sample placed on a prism. As the concentraon of a liquid increases, so does the degree to which the light is bent or refracted. A Brix refractometer assesses the percent of sucrose, or sugars, in a soluon, measuring in “degrees Brix.” “Brix” is not a brand name, but rather, a specific measurement of sucrose content. One degree on a Brix scale is equal to 1 gram of sucrose in 100 grams of soluon. Colostrum quality control Brix refractometers are growing in popularity as an on-farm tool to assess colostrum quality. They are more durable than other colostrum testers and are fairly consistent using the refracon of light through colostrum to esmate colostrum quality and ulmately, immunoglobulin-G (IgG) levels. Many calf raisers use visual appraisal and volume of first-milking colostrum to assess colostrum quality. Despite these evaluaons, research has shown colostrum from one cow to the next can range in IgG content – from as low as 20 mg/mL IgG to as high as 100 mg/ mL. Without assessing IgG levels, calf raisers risk failure of passive transfer of immunity in newborn calves. A Brix value of 22-23 has been shown to correlate with 50 mg IgG/mL, which is oſten used as the cut-off point for high-quality colostrum. The reading can easily be taken as colostrum is harvested since many models of refractometers compensate for temperature. It is highly valuable in separang high-quality colostrum from low-quality colostrum, thus giving every calf the opportunity for successful passive transfer of immunity. 1 Waste milk consistency More recently, dairy producers have started using Brix refractometers to help improve the consistency of waste milk fed to calves, which has been shown to promote preweaned calf growth. Over me, the industry has learned the importance of delivering a consistent, high-quality product to young calves. That’s also why pasteurizaon, to kill bacteria in waste milk, has become such a widespread pracce. Likewise, on-farm studies have shown the solids content of waste milk can be highly inconsistent. Washington State University researchers evaluated the solids content of samples from several batches of waste milk sold to a large western calf ranch. They found that solids levels varied widely from the standard level of 12.5 percent for whole milk. In a few cases, solids levels were higher than 12.5 percent, likely due to colostrum or transion milk included in the waste milk. But many more samples were below 12.5 percent, dipping to as low as 6.7 and 5.1 percent, respecvely, for two samples.[1] Calves fed waste milk low in solids may not receive adequate nutrion for opmal growth and health. The likely cause of low solids levels in waste milk is added water. Oſten, waste milk is not handled as carefully as salable milk, and wash water may inadvertently be mixed with it.