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Total Serum Protein Measurements
In Calves Fed Calf’s Choice Total™Colostrum
Article by: Dr. Stephen D. Acres, DVM, PhD, President & CEO of The Saskatoon Colostrum Co. Ltd.
The use of refractometers to measure total protein levels in calf serum has become a common method of monitoring colostral immune status and feeding practices. This is based on the fact that after colostrum feeding a portion of the proteins in colostrum is absorbed from the calf’s intestine into its blood during the first 24 hours of life. However, this practice has several limitations even when maternal colostrum is fed, and the results differ when colostrum replacers are used. The following study shows that the average totoal protein levels in cavles fed Calf’s Choice TotalTM (CCT) colostrum are below the commonly recommended target of 5.0g/dl even though their average serum IgG levels exceed the recommended minimum level of 10g/L.
Colostrum contains two categories of proteins:
i) immune proteins, the most notable one being IgG, that protect calves from infectious diseases, and
ii) non-immune proteins, such as casein, that do not prevent diseases.
Together the immune and non-immune proteins make up the total proteins. However, because the ratio of immune to total proteins varies widely in colostrum, the correlation between immune protein and total protein levels is not strong. Therefore total protein measurements provide only an estimate of immune status and the accuracy of that estimate can be affected by the assays used for measurement, the amount and quality of colostrum fed, the age at which the calf is sampled, and the total protein level in the calf before colostrum feeding.
Because of these variables outlined in the blue box, the manufacturer of the Calf’s Choice Total™ family of colostrum products, The Saskatoon Colostrum Company Ltd, fed each CCT product to a group of Holstein bull calves and then measured the levels of serum IgG and total protein in the calves at 24 to 36 hours of age. Total protein was measured by three different methods, a hand held refractometer (least sensitive), a digital refractometer, and a laboratory spectrophotometer (the most sensitive). IgG levels were measured in a laboratory using a radial immunodiffusion (RID) assay standardized with a serum sample obtained from the USDA/APHIS.
The results are summarized in Figures 1 and 2 and guidelines for producers who want to monitor total protein levels in calves fed Calf’s Choice Total™ products are shown in Figure 3. Since a hand held refractometer is the most common method used on the farm, those results are highlighted in the following summary. Please note that to prevent Failure of Passive Transfer (FPT) calves should have a minimum of 10g/L of serum IgG after colostrum feeding.
Summary
Calves Fed 1 Replacer Dose of Calf’s Choice Total™ (See Figure 1)
Average serumIgG levels were above the minimum recommended level of 10g/L in calves fed all CCT products.
- Average serum total protein levels were below the normally recommended level of 5.0g/dl when measured using a hand held refractometer, and averaged 4.6 g/dL, 4.5 g/dL, and 4.6 g/dL in calves fed CCT-Gold, -Silver, and –Bronze respectively (See Figure 3).
Calves Fed 11/2 or 2 Doses of Calf’s Choice Total™ (See Figure 2)
Average serum IgG levels were above 15g/L in all groups, much higher than the minimum target of 10g/L.
- Average serum total protein levels were 4.9g/dL (CCT-Gold), 5.0g/dL (CCT- Silver), and 5.2g/dL (CCT-Bronze).
Guidelines for producers who want to monitor total serum protein levels in calves being fed Calf’s Choice Total™ (see Figure 3)
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Posted Jun 19th
