Research shows that a calf’s colostral antibody requirement for adequate passive transfer is about 80 to 100 grams. However, don’t assume a colostrum replacer that contains that level or more of immunoglobulin will deliver adequate passive transfer.

According to a new study in the June Journal of Dairy Science, the IgG content listed on the label can be “an inadequate predictor” of the product’s effectiveness.

During the study, researchers at North CarolinaStateUniversity enrolled Holstein bull calves in one of three treatments. The first group received 4 quarts of colostrum within three hours of birth. The second group received two bags of a commercial colostrum-replacement product equivalent to 90 grams of IgG. Calves in the third group received three packages of the same product equivalent to 135 grams of IgG. All calves were fed via an esophageal feeder within three hours of birth. The IgG concentration of the maternal colostrum fed in the study was not available.

The calves fed either two or three bags of colostrum replacer had much lower serum total protein and serum IgG concentrations than calves fed fresh colostrum. They also had significantly higher failure of passive transfer. The table below provides some of the study results.

Previous studies also show commercial colostrum replacers are not always effective. The exception appears to be serum-based colostrum replacer products. Studies using some of those products have resulted in successful passive transfer, says Geof Smith, veterinarian at North CarolinaStateUniversity.

The researchers also say that there appear to be a number of factors that influence the efficiency of absorption of colostrum-replacement products. Those factors include source of IgG, method of IgG fractionation, amount and type of non-IgG protein, and the effect of fat and lactose on absorption efficiency. “Simply examining the mass of IgG provided by the colostrum replacer is not an adequate measure of product efficacy,” they say. For best results, evaluate each product for effectiveness prior to use.

  Average serum IgG  Average serum total protein Failure of passive transfer1
Group mg/dL g/dL (%)
Fresh colostrum   1,760 5.4 5
Two bags colostrum replacer 750 4.4 95
Three bags colostrum replacer 910 4.7 76









1Failure of passive transfer was defined as a serum IgG concentration less than 1,000 mg per deciliter.

Source: Adapted from June 2007 Journal of Dairy Science, page 2905-2908.