FROM THE FARM REPORT: THE GOLDILOCKS CONUNDRUM OF GOLDEN COLOSTRUM
- Sarah Morrison
- 2 days ago
- 3 min read
Traditionally we have promoted, myself included, a set volume and quality of first feeding colostrum to calves. Often we recommend 4 L or one gallon of high quality colostrum within the first two hours after birth to our large breed calves. However, this blanket approach might not be what’s best for each individual calf and maybe we should be incorporating a precision feeding mindset when implementing our colostrum feeding recommendations. Not every calf is the same size at birth, so should we be adjusting target colostrum volume based on this very basic metric?
A recent study published in the Journal of Dairy Science (Frederick et al., 2025; https:doi.org/10.3168/jds.2025-27228) sought to address this question. Researchers at Cornell and the University of Guelph evaluated the effect of feeding colostrum at 6, 8, 10, and 12% of birth body weight on IgG absorption, gastric emptying, and post feeding behavior. Each calf was weighed and the amount of colostrum adjusted based on their birth body weight (BBW) to meet the different colostrum feeding rates for the study. This study was conducted on a commercial farm in New York, and all calves were tube fed the first feeding of colostrum. The average weight of the calves on the study was 88 lb (40 kg) with a range of 70-108 lb (31.8-49.1 kg)
The average colostrum quality for the study was within the recommendations and averaged 24.2% measured on the Brix refractometer with a range of 21.2-29.6% or 86.7 g/L of IgG with a range of 73.2-121.1 g/L. Traditional recommendations suggest colostrum quality >22% Brix and > 50 g/L of IgG.
Calves’ intake of colostrum is summarized in the first table based on the data presented in the article. Calves fed 6% consumed 2.3 L on average while those fed at 12% consumed 4.8 L on average. As a result of similar quality of colostrum offered to calves but varied volumes, calves fed at 6% consumed 215 g IgG while calves fed 12% consumed 429 g of IgG.
Overall the serum IgG, an indication of transfer of passive immunity, was very good across all treatment groups. The standouts were certainly the calves fed 10 or 12% of BBW, where all of the calves achieved excellent IgG classification according to the four-category system developed by Lombard et al., 2020. Calves fed either 6 or 8% had more calves fall within the good or fair category.
As colostrum volume increased the apparent efficiency of absorption decreased. The authors measured gastric emptying using acetaminophen in the colostrum and measuring how much showed up in the blood as an indication about how much colostrum had passed from the abomasum to the small intestine. Calves fed colostrum at 6% of BBW had the fastest gastric emptying while calves fed at 12% of BBW had the slowest. The reduced apparent efficiency of absorption might be attributed to the increased viscosity and residence time in the abomasum. If the passage was slower with the 12% feeding program the passage of IgG to the small intestine, where the IgG absorption occurs, was likely delayed.
The time budget of the calves (standing and lying behavior) wasn’t impacted by colostrum feeding volume, but the authors noted some signs of discomfort for calves fed either 10 or 12% of BBW, with a couple calves noted for regurgitation on the higher volumes fed.
This study only evaluated a single colostrum feeding. Therefore, additional information may be warranted to look at this range of first colostrum intake paired with subsequent feedings of colostrum. Furthermore, this study looked at tube feeding all calves. While this may be a practical approach to ensure calves get colostrum in a timely manner, it would be interesting to compare this practice to bottle-fed calves. The tradeoff of ensuring that first meal is consumed and the time needed to achieve this is something that I think many calf feeders struggle with. However, previous studies have shown no difference in transfer of passive immunity between these two practices.
The take home messages from this study are that we should target a feeding volume between 8 and 10% of BBW of high-quality colostrum to achieve appropriate serum IgG concentrations. The target volumes based on birth body weight are summarized in the second table for a guide on farm if you would like to follow these recommendations.
— Sarah Morrison
