Dr. Grazyne Tresoldi, Assistant Professor, Animal Welfare, Department of Animal Sciences, The Ohio State University
Most dairy producers recognize the importance of colostrum and have protocols in place to manage it. However, data show that a meaningful proportion of calves still fail to achieve optimal passive immunity, and research increasingly indicates that achieving excellent passive immunity provides calves with a greater margin of protection and resilience. Together, these findings highlight opportunities to strengthen even well-established programs by focusing on consistency and measurable outcomes.
This article is the first in a four-part series on feeding pre-weaned calves and focuses on establishing a strong foundation through effective and excellent colostrum management.
Why Colostrum Comes First
Colostrum feeding is the most time-sensitive and biologically critical feeding decision in a calf’s life. Calves are born without circulating antibodies because the placenta prevents transfer of maternal immunoglobulins, leaving them without immune protection at birth. Colostrum is therefore the calf’s sole source of early immune protection.
Beyond antibodies (primarily IgG), colostrum provides hormones, growth factors, and other bioactive compounds that support early immune function and intestinal development. Failure of passive transfer cannot be fully corrected later; even strong milk feeding and calf management programs cannot compensate for inadequate early immunity. For this reason, colostrum management should be viewed not only as disease prevention, but as the first step in building calf resilience, welfare, and long-term performance.
The Four Pillars of Colostrum Management
Effective colostrum programs rest on four key principles: timing, quality, quantity, and cleanliness.
- Timing: Colostrum should be fed as soon as possible after birth, ideally within the first 1 to 2 hours, as the calf’s ability to absorb antibodies declines rapidly after birth.
- Quality: Colostrum quality varies among cows. Measuring quality with a Brix refractometer helps ensure calves receive colostrum capable of delivering sufficient antibodies. While preventing failure of passive transfer remains essential, higher antibody concentrations are associated with improved protection and resilience.
- Quantity: The goal of colostrum feeding is to deliver adequate IgG, not simply a fixed volume. In practice, this often means feeding colostrum equivalent to 10 to 12% of body weight at the first feeding, adjusted based on measured quality.
- Cleanliness: Bacterial contamination interferes with antibody absorption and increases health risk. Clean collection, storage, and feeding equipment are therefore critical to colostrum program success.
It is important to note that colostrum quality begins before birth. Proper dry cow nutrition and strategic dry cow vaccination increase pathogen-specific antibodies in colostrum, strengthening protection for the newborn calf. Vaccination complements, but does not replace, effective colostrum handling and delivery.
Measuring Success: From Adequate to Excellent
Measuring colostrum quality indicates what was offered to the calf; measuring the calf confirms whether the system worked. Testing serum total protein or serum IgG at 24 to 48 hours of age provides valuable feedback on passive transfer success.
Historically, the goal of colostrum management has been to avoid failure of passive transfer. Newer frameworks recognize that calves achieving excellent passive transfer have higher circulating antibody levels, providing a greater margin of protection and resilience to common stressors. Aiming for excellence shifts colostrum management from risk avoidance to performance optimization.
What About Calves that Nurse the Dam?
Nursing can be effective when calves nurse promptly, consume sufficient high-quality colostrum, and do so under clean conditions. However, intake volume and timing are difficult to verify, and delayed or incomplete nursing is common.
Because antibody absorption declines quickly after birth and colostrum quality varies among cows, nursing-based systems benefit from the same outcome-based monitoring described above. Targeted supplementation or partial hand-feeding can improve outcomes without abandoning nursing-based systems.
Colostrum Beyond Day One
Although antibody absorption effectively ends within the first day of life, colostrum and transition milk continue to support gut maturation and local immune function. Feeding colostrum or transition milk during the first few days of life can help calves adapt to their environment and support overall resilience during this critical period.
Take-home Message
Colostrum feeding is not simply about avoiding failure. Programs that deliver colostrum promptly, in sufficient quantity and quality, and under clean conditions provide the opportunity for excellent passive immunity, supporting calf welfare, robustness, and lifetime performance (Table 1). Everything that follows in the calf-feeding program builds on this foundation.
In the next article of this series, we will focus on milk feeding after colostrum, exploring how milk allowance and feeding strategies influence welfare and long-term productivity.
Table 1. Key benchmarks: Colostrum feeding for dairy calves.
|
Management area |
Target / Benchmark |
Why It Matters |
|
Timing |
Feed as soon as possible after birth; ideally within 1 to 2 hours |
Antibody absorption declines rapidly after birth, reducing passive immunity with delays. |
|
Quality |
Minimum: ≥ 22% Brix (≈ ≥50 g IgG/L) |
Higher IgG concentration increases the likelihood of achieving excellent passive immunity and greater resilience. |
|
Quantity |
10 to 12% of body weight at first feeding (adjust based on measured quality) |
Adequate IgG delivery, not just volume, determines immune protection. |
|
Cleanliness |
Clean collection, storage, and feeding equipment |
Bacterial contamination interferes with antibody absorption and increases health risk. |
|
Monitoring passive transfer |
Minimum: Serum IgG ≥ 10 g/L or serum total protein ≥ 5.5 g/dL Excellence: Serum IgG ≥ 25 g/L or serum total protein ≥ 6.2 g/dL |
Higher antibody levels provide a greater margin of protection and resilience to common stressors. |
Selected References:
Godden, S. M. (2008). Colostrum management for dairy calves. Veterinary Clinics of North America: Food Animal Practice, 24(1), 19–39. https://doi.org/10.1016/j.cvfa.2007.10.005
Lombard, J. E., Urie, N. J., Garry, F. B., et al. (2020). Consensus recommendations on calf- and herd-level passive immunity in dairy calves in the United States. Journal of Dairy Science, 103(8), 7611–7624. https://doi.org/10.3168/jds.2019-17955
Quigley, J. D., Lago, A., Chapman, C., Erickson, P., and Polo, J. (2013). Evaluation of the Brix refractometer to estimate immunoglobulin G concentration in bovine colostrum. Journal of Dairy Science, 96(2), 1148–1155. https://doi.org/10.3168/jds.2012-5823
Renaud, D. L., and Steele, M. A. (2025). What can’t colostrum do? Exploring the effects of supplementing colostrum after the first day of life: A narrative review. Journal of Dairy Science Communications, 6(3), 469–473. https://doi.org/10.3168/jdsc.2024-0708
Weaver, D. M., Tyler, J. W., VanMetre, D. C., Hostetler, D. E., and Barrington, G. M. (2000). Passive transfer of colostral immunoglobulins in calves. Journal of Veterinary Internal Medicine, 14(6), 569–577. https://doi.org/10.1111/j.1939-1676.2000.tb02278.x