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Using meters to measure feed quality

Fairly simple tools are available to evaluate colostrum and milk

This calving season arrived in the midst of a worldwide vitamin A, D and E shortage. The quality of colostrum depends greatly on maternal nutrition. The health and viability of the young depends on the quality of the colostrum. So how can farmers test the quality of their calf colostrum/milk at home? There is a way!

Our family enjoys science. It is exciting being able to understand how things work and do experiments to better our animal husbandry. On a trip to the feed mill, my son noticed a promotion for a free refractometer.

Refractometers are optical instruments which measure the amount of light refracted, or bent, as it passes through a liquid. We have been curious about them for testing feed but Mapleview Agri, the company supplying these meters, wanted them used by farmers to test colostrum.

There is another tool called a colostrometer. While some scientists find it more effective than the refractometer to visually test colostrum quality, it has disadvantages — the major one that they were designed for use in a lab. The results are tied to the temperature of the colostrum and require one cup of colostrum to test. The refractometer requires only a drop, which is much handier when milking a first-time beef heifer.

As result, as a commitment to helping their customers improve calf health, Mapleview Agri was promoting the use of refractometers to ensure quality colostrum. The video (www.youtube.com/watch?v=vixnjh1SJrE) has visuals to show how to read the refractometer and make sure it is calibrated properly. The package insert also has detailed instructions.

My research showed this is not a new idea. According to researchers at Penn State University, the Brix scale works to measure colostrum on the theory that antibodies represent a large portion of the protein in colostrum, so the level of antibodies in the sample is highly correlated to the amount of light refracted.

Readings of 18 to 21 per cent indicate colostrum that can be used for second feedings and readings 17 per cent and lower should not be used without colostrum supplements.

The experiment was done on older cows as well as first- and second-calving heifers. We were thrilled to see that our Brix reading was consistently above 22 per cent. It was interesting to see it really didn’t vary much from cow to cow which we thought it might. Further reading into this kind of research found that Penn State also used the refractometer for published formulas for evaluating milk solids. Unfortunately scientists are of the opinion using the refractometer to test milk replacer batches is not reliable. The meter is a reliable tool to check the solids of waste milk being fed to calves.

Evaluating milk quality

The Brix meter can be used to evaluate waste milk fed to older calves to ensure it is of a consistent quality. Guidelines established say normal milk should measure 12.5 to 13 per cent total solids. Although the Brix refractometer measures the amount of sugar in a sample, the result can be converted to estimate total solids in milk. This is the equation developed by Penn State:

Total solids=(0.9984 x Brix reading) + 2.077

For example, a Brix reading of 10.4 equals 12.5 per cent total solids, while a reading of 10.9 equals 13 per cent total solids.

Pasteurized waste milk can be checked before feeding with the solids concentration adjusted by adding milk replacer.

This is the kind of technology that will help us to be better farmers. The fact that we can use these refractometers on farm to instantaneously test each and every female, or even your grass, without waiting for results, is a huge help.

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