Bovine colostrum is the first milk a cow produces in the first few days after giving birth. It is much richer in protein than regular milk (about 15% versus 3% on day one) and is packed with immunoglobulins, lactoferrin and growth factors that help protect a newborn calf. Supplements gently dry it into a powder.
Key takeaways
- Colostrum is the milk made straight after calving, usually collected up to about day 3 (Playford and Weiser, 2021).
- First-day colostrum is roughly 15% protein, compared with about 3% in regular milk.
- Immunoglobulins (antibodies) make up 70–80% of colostrum protein, versus around 1% in mature milk.
- Calves are born without meaningful antibody protection, so colostrum is their first line of support.
- Quality varies a lot: commercial colostrum products can differ up to six-fold in bioactivity.
What exactly is colostrum?
All mammals, including humans, produce colostrum. It is the thick, golden first milk made in the hours and days after birth, before regular milk comes in. "Bovine" simply means it comes from cows.
For a calf, colostrum is more than food. A cow's placenta (a type called epitheliochorial) stops antibodies passing from mother to calf during pregnancy, so calves are born with very little immune protection of their own (Robbers et al., 2021). Colostrum fills that gap. A newborn calf's gut can absorb these large antibody proteins best immediately after birth, and that ability declines over the following hours. That is why farmers put so much emphasis on calves getting colostrum early.
If you'd like the bigger picture before diving into the detail, our Colostrum 101 guide covers the basics in a few minutes.
When is colostrum produced?
Colostrum is most concentrated at the very first milking and gradually changes into regular milk over the next few days. Researchers describe colostrum as being collected up to around day 3 after calving (Playford and Weiser, 2021). After that, the milk becomes "transitional" milk and then "mature" milk, the everyday milk you'd pour on your cereal.
Because the first milking is the richest, when colostrum is collected has a big influence on how much of each bioactive ends up in the final product.
How is colostrum different from regular milk?
Side by side, colostrum and mature milk are surprisingly different. Colostrum is higher in protein and fat (around 7%) and lower in lactose (around 2.5%) than regular milk, and it carries far higher levels of protective proteins (Playford and Weiser, 2021). A 2021 review estimated colostrum contains 50–300 times more immunoglobulins and up to 250 times more lactoferrin than mature milk (Davison, 2021).
| Component | Colostrum (early milkings) | Mature milk | Source |
|---|---|---|---|
| Protein | About 15% (day 1) | About 3% | Playford and Weiser, 2021 |
| Immunoglobulins, share of protein | 70–80% | About 1% | Playford and Weiser, 2021 |
| Lactoferrin | 1.5–5 mg/mL | 0.02–0.75 mg/mL | McGrath et al., 2015 |
| IGF-1 (a growth factor) | 50–2,000 µg/L | Under 10 µg/L | McGrath et al., 2015 |
| TGF-β1 (a growth factor) | 12–43 µg/L | 0.8–3.5 µg/L | McGrath et al., 2015 |
What's in bovine colostrum?
Colostrum is a complex mix of nutrients and bioactive compounds. The main players are:
- Immunoglobulins. IgG makes up roughly 85–90% of the immunoglobulins in bovine colostrum, with IgA and IgM making up most of the rest (Robbers et al., 2021). Our guide to immunoglobulins explained simply goes deeper.
- Lactoferrin. An iron-binding protein found at 1.5–5 mg/mL in first-milking colostrum (McGrath et al., 2015).
- Growth factors. Including IGF-1 and TGF-β1, both far more concentrated than in regular milk.
- Lysozyme. A naturally occurring enzyme also found in tears and saliva.
- Proline-rich polypeptides. A mixture of at least 32 small peptides (Playford and Weiser, 2021).
- Oligosaccharides. Complex sugars, mostly sialylated, with 3′-sialyllactose making up about 70% (McGrath et al., 2015).
For more on the less famous components, read lactoferrin, growth factors and other colostrum bioactives.
How is colostrum made into powder?
Liquid colostrum is perishable, so it is processed into a stable powder. Broadly, it is collected, chilled, pasteurised and dried. The key challenge is heat: immunoglobulins are delicate proteins.
Commercial colostrum is typically batch pasteurised at relatively low temperatures of 60–63°C (Playford and Weiser, 2021). That matters, because research shows heating at 60°C for 30–60 minutes barely affects IgG (Robbers et al., 2021), while IgG starts to be affected above about 65°C and loses immunoreactivity at 72°C (Bogahawaththa et al., 2017). One review noted some pasteurisation methods cut IgG by around 60% (Davison, 2021).
Processing choices like these help explain why commercial products can vary up to six-fold in bioactivity (Playford and Weiser, 2021). MUUU Colostrum Powder is 100% pure bovine colostrum from New Zealand with no other ingredients: one level teaspoon (2 g) provides 2,000 mg of colostrum.
Why do people take colostrum supplements?
Most human research has looked at two areas: immune support and gut health, often in people doing heavy exercise. You can read what the studies found in colostrum and immune support and colostrum and gut health.
One important detail: study doses were often 10–20 g a day, and some went up to 60 g (Davison, 2021). That is considerably more than one standard supplement serve, so it's worth keeping in mind when you read about research results.
FAQs
Is colostrum just milk?
Technically it's the first milk, but it's very different from the milk in your fridge. It has around five times the protein on day one, and immunoglobulins make up most of that protein. Think of it as milk's concentrated, protective starter version.
What does colostrum powder taste like?
Good-quality colostrum powder has a mild, creamy, milky taste. MUUU Colostrum Powder dissolves with a stir, so it blends easily into smoothies, yoghurt and cool or warm drinks. No need to have a cow about the flavour.
Does colostrum contain lactose?
Yes. First-day colostrum contains about 2.5% lactose, which is lower than regular milk but not lactose-free. It also contains milk proteins, so it isn't suitable for people with a cow's milk allergy. See is colostrum safe? for more.
How much colostrum is in one serve?
It depends on the product. A level teaspoon of MUUU Colostrum Powder is 2,000 mg, and two MUUU capsules are 1,000 mg. Always follow the directions on the label.
References
- Playford RJ, Weiser MJ. Bovine colostrum: its constituents and uses. Nutrients. 2021;13(1):265. https://www.mdpi.com/2072-6643/13/1/265
- McGrath BA, Fox PF, McSweeney PLH, Kelly AL. Composition and properties of bovine colostrum: a review. Dairy Sci Technol. 2016;96:133–158 (published online 2015).https://link.springer.com/article/10.1007/s13594-015-0258-x
- Robbers L, et al. Front Vet Sci. 2021. https://doi.org/10.3389/fvets.2021.668639
- Davison G. The use of bovine colostrum in sport and exercise. Nutrients. 2021;13(6):1789. https://www.mdpi.com/2072-6643/13/6/1789
- Bogahawaththa D, et al. Food Hydrocolloids. 2017;72:350–357. https://doi.org/10.1016/j.foodhyd.2017.06.017
This article is general information, not medical advice. Always read the label and follow the directions for use.
