Ensuring that newborn calves receive high quality colostrum shortly after birth is one of the most important decisions a dairy producer can make to influence the future productivity of their herd. The use of a Brix refractometer, a simple handheld optical device, allows farmers to estimate immunoglobulin (IgG) concentration in colostrum quickly and cost-effectively. While inexpensive and easy to use, its long-term impact, particularly in the form of reduced disease incidence and boosted milk production, makes it a highly valuable tool in raising profitable, high-performing replacement heifers.
Colostrum quality matters
Calves are born without circulating antibodies (agammaglobulinemic), meaning they lack antibodies at birth due to the structure of the bovine placenta, which does not allow for the in utero transfer of maternal immunoglobulins. Therefore, passive immunity is entirely dependent on the timely ingestion and absorption of colostrum — the first milk produced by the cow after calving.
Colostrum is rich in IgG, and effective transfer of passive immunity occurs when the calf absorbs at least 150 to 200 grams of IgG within the first 12 hours of life, ideally within the first two hours. Failure of passive transfer (FPT), defined as a serum IgG concentration less than 10 grams per liter (g/L) at 24 to 48 hours after birth, is still reported in 13% to 25% of dairy calves across the United States, even with widespread awareness.
Calves with FPT are at a significantly higher risk of experiencing diarrhea, pneumonia, navel infections, and even death. Beyond that, FPT has been associated with reduced average daily gain (ADG), delayed age at first calving (AFC), and lower milk yields in later lactations. These lifelong consequences underline the economic importance of colostrum management as a foundational herd health strategy.
Continue reading this article published in Hoard’s Dairyman.
