Colostrum Replacers and Supplements: Tools to Increase Calf Immunity

by Kelly Driver

Providing the newborn calf with colostrum, ideally within the first 4 hours of life, is vital to helping it achieve passive immunity. But have we considered what to do when good quality maternal colostrum is not available? A good quality colostrum replacer can provide the healthy alternative.

Failure of passive transfer is big risk. Calves that experience failure of passive transfer (FPT) are more likely to become sick or die in the first two months of life than calves that have adequate immunity. FPT is defined as a blood IgG level less than 10 mg/mL at 24-48 hours after birth. There are many factors that can influence FPT, but the most common revolve around colostrum quality, management, and feeding. Research shows that calves should be fed a minimum of 100 g of IgG within 4 hours of birth, and feeding 150-200 g of IgG is generally recommended to assure plenty of IgG is available for the calf to absorb. (Penn State) We also know that there is a lot of variability in colostrum quality between individual cows, so all colostrum should be tested to ensure only the desired quality is being fed to newborn calves. When available colostrum is low in quality, calf managers may decide to feed either a supplement or colostrum replacer.

Is it a Supplement or Replacer? Colostrum replacers are made from either bovine colostrum or serum and contain 100-150 g of IgG per dose. These products also provide fat, protein, vitamins and minerals, but there is variance among products on the market. For example, fat content can vary widely, but a colostrum replacer will provide more immunoglobulin to the newborn than a supplement product or poor-quality colostrum. When reading the labels, you may find products labeled as “real” colostrum, meaning they contain dairy cow colostrum that has been dried down and heat-treated to eliminate harmful operatives like mycoplasma or Johne’s disease. Serum-based products are the result of blood collected to serve as the antibody source for the newborn calf. These products can transfer IgG to the calf, but can be lacking in the other maternal cells and hormones that are so vital to the newborn calf’s immune system.

There is no way of guaranteeing the effectiveness of a product unless it has been licensed by the USDA Center for Veterinary Biologics. Colostrum supplements are products that are unable to raise the blood concentration of IgG above 10 mg/mL for calves. These products may be used to increase the amount of IgG fed to calves when only lower quality colostrum is available. However, research has shown that when a supplement is added to low quality colostrum, the IgG is often absorbed poorly and FPT rates are higher as shown in the table below. This table summarizes the results of 26 different research trials published in peer-reviewed journals that used nearly 90 different treatments studying colostrum replacer and supplement products and provides a good overview of the various categories performance on average.

Summary of treatment means from 26 published studies investigating colostrum products
Number of MeansAverageMaximumMinimum
IgG Intake, g
Maternal Colostrum1920344753
Colostrum-based Replacer2112621018
Serum-based Replacer3012926053
Colostrum-based Supplement815729785
Serum-based Supplement49610090
Serum IgG, mg/mL
Maternal Colostrum2516273
Colostrum-based Replacer2111202
Serum-based Replacer309165
Colostrum-based Supplement810205
Serum-based Supplement69117
Apparent Efficiency of Absorption, %
Maternal Colostrum16233610
Colostrum-based Replacer14335112
Serum-based Replacer22253815
Colostrum-based Supplement712266
Serum-based Supplement4323825
Source: Penn State Extension Service

Be certain to read the label. Too often colostrum products are selected solely on price, but with many different products on the market, it is very important to look at the labels closely. Since IgGs are the antibodies that provide the newborn calf’s early defense against pathogens, it is important to find a product that guarantees a specific IgG level. Some products may be labeled as providing 120 grams of globulin protein, but in fact deliver less than the crucial 100 g of IgG needed for the calf’s immunity. Globulin proteins actually include other proteins along with the IgG antibodies, so the number can be misleading of the actual effectiveness of the product.

Read and follow the manufacturer’s instructions for feeding. Some products are mixed with water and others are added to existing colostrum, and the number of feedings recommended can also vary. Other products, including those packaged in bulk, offer the option of selecting the IgG dose by using different amounts of powder.

The difference in IgG dosage was studied by Godden et al., (2009a), to determine whether feeding two doses of a colostrum replacer (CR) had further benefit to IgG levels in calves and whether the benefits included all classes of IgG. Each treatment dose contained an IgG concentration of 66.7 g/L, so treatment one received 1.5L and treatment 2 was 3L by volume fed. Treatment group 3 was fed 3.8L of colostrum harvested 20-60 minutes after calving from the dam or stored refrigerated colostrum from one other cow if the dam’s colostrum was not available. All calves in the study were single births, weighing at least 70 lbs., with a calving ease score of less than or equal to 3 on a scale of 1 to 5. All calves were fed the same commercial milk-based replacer after their colostrum feeding. The results shown in the table below and underline that the 24-hour samples for serum protein and IgG in the calves did not differ between 2-dose CR and colostrum, but were greater than 1-dose CR. The apparent efficiency of absorption (AEA) was similar on all treatments, but much better rates of adequate passive transfer (APT) occurred on the 2-dose and colostrum treatments.

1-dose CR2-dose CRColostrum
Calves, n=242322
Birth weight, lb.83.586.389
Post calving fed, minutes504444
Total IgG fed, g100a200b271c
Precolostral sample
Serum protein, g/dL4.54.44.4
IgG, mg/mL0.480.360.38
24-hour sample
Serum protein, g/dL4.9a5.5b5.7b
IgG, mg/mL9.6a19.0b20.7b
AEA IgG, %35.536.531.8
Calves with APT, n (%)13 (54)a23 (100)b20 (91)b
Total Ig, mg/ml20.524.5
Source: Kertz from Godden, et al. research
AEA = apparent efficiency of absorption of IgG.
APT = adequate passive transfer (serum IgG at 24 hr. > or = 10.0 mg/mL).
abc Means with different superscripts within a row differ (P<0.05).

High quality maternal colostrum is still the best option for feeding newborn calves. However, there are times and circumstances when colostrum replacer or supplement products can be valuable tools to have available. When selecting a product to use, it is very important to understand if the product is USDA licensed, what the IgG level is, to follow mixing directions carefully, and how many doses should be fed to deliver the calf a minimum of 100 g of IgG within 4 hours of birth.

Kelly Driver has been involved in the New York dairy industry all her life. In addition to raising dairy calves and replacement heifers, she is the Northeast Territory Manager for Calf-Tel. Feel free to contact her at with your calf questions or suggest a topic you would like covered in a future blog.


Godden, S.M., D.M. Haines, and D. Hagman. (2009a). Improving passive transfer of immunoglobulins in calves. I: dose effect of feeding a commercial colostrum replacer. Journal of Dairy Science, 92:1750-1757.

Kertz, A.F. (2009). Calf colostrum replacer can meet IgG needs. Feedstuffs. September 14, p.12.

Lago, A., M. Socha, A. Geiger, D. Cook, N. Silva-del-Rio, C. Blanc, R. Quesnell, and C. Leonardi. (2018). Efficacy of colostrum replacer versus maternal colostrum on immunological status, health, and growth of preweaned dairy calves. Journal of Dairy Science, 101: 1344-1354.

Penn State Extension Service. (2020, April). Colostrum supplements and replacer. American Dairymen, vol. 45, no. 4: 28-32.

Priestley, D., J.H. Bittar, L. Ibarbia, C.A. Risco, and K.N. Galvao. (2013). Effect of feeding maternal colostrum or plasma-derived or colostrum-derived colostrum replacer on passive transfer of immunity, health, and performance of preweaning heifer calves. Journal of Dairy Science, 96: 3247-3256.


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