New Transfer of Passive Immunity Standard

Mar 14, 2023 | Educational Blog

New Serum IgG Standards

There has been a long-standing definition of successful transfer of passive immunity, stated as 10 grams of IgG per liter of serum, 24-36 hours post colostrum feeding. The United States Department of Agriculture has raised the standard.

A recent publication citing transfer of passive immunity data1 and subsequent morbidity and mortality, demonstrated that calves achieving higher levels of IgG transfer, demonstrated lower mortality and significantly less episodes of illness. It was also concluded there are increased benefits, especially health, in achieving higher levels of transfer of passive immunity. Additionally, considerable lifetime calf health and production advantages can be achieved by achieving high good to excellent levels of serum IgG (20-25 grams of IgG/Liter of calf serum, 24 hours post colostrum feeding).

Brix & IgG Scale

A controlled research study completed at Penn State University2 on 80 newborn Holstein calves, demonstrated that First Day Formula® CR (manufactured with a whey-based colostrum ingredient), is a viable supplement to be added directly to good IgG level maternal colostrum to achieve excellent transfer of passive immunity. The increase can be attributed to the whey-based colostrum ingredient having a higher concentration of IgG and being more soluble than whole colostrum-based ingredients. The combination of 50 grams of IgG from whey-based colostrum replacer and maternal colostrum achieved the highest level of IgG absorption in the study.
To achieve “excellent” colostrum, test maternal colostrum with a Brix Refractometer to determine quality and IgG scale. If Brix percent is 18-24, add 166 grams (containing 50g of IgG) of First Day Formula CR to maternal colostrum and mix thoroughly. Retest colostrum after supplementation to ensure excellent standard is met.

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