Thursday, December 29, 2016

Irish Colostrum Bacteria Counts

An Irish study included colostrum collected from 49 cows that calved between February 9 and March 5, 2014. All the cows were milked as soon as practical after calving. The colostrum was very high quality averaging 94g/L (the lowest quality was 62g/L). They fed colostrum at the rate of 8.5% of birth weight. [40kg or 88lb. calf received 3.4kg or 7.5lbs colostrum] [7.5lbs = 3.5quarts]

There were five colostrum handling and feeding treatments:
1. [PST] Pasteurized and fed immediately after collection
2. [FR] Raw, fed immediately after collection
3. [ST4] Stored for 2 days at 4C
4. [ST13] Stored for 2 days at 13C
5. [ST22] Stored for 2 days at 22C

The total plate count sampled before feeding the calf by storage treatment was:

1. PST   = 35, 148
2. FR     = 372,907
3. ST4   = 1,198,947
4. ST13 = 7,509,309
5 ST22 = 54,865,583

Pretty much as you would have predicted?

Now here is the interesting conclusion of the authors:

"Although all precautions were taken in the present study to minimize bacterial contamination during colostrum collection, total bacteria count of the fresh colostrum in the present study was almost 400,000cfu/ml, exceeding the current suggested maximum bacteria level of 100,000cfu/ml. Because cleaned equipment was used for collection, the present recommendations may be unrealistic in a commercial setting." (p532) [emphasis added]

I do not agree with this conclusion. I have commercial dairy clients both large and small herds that consistently provide "as-fed" colostrum under 50,000cfu/ml total plate count. 

Furthermore, there are regular variations between farms on these colostrum bacteria counts with some farms producing consistently clean colostrum and others that do not have adequate collection and handling procedures to keep their total plate counts under 100,000cfu/ml. Low bacteria counts are both possible and practical - the key is good management.

In our veterinary clinic in-house lab I tell the technicians not to bother quantifying samples over 100,000cfu/ml because the colostrum is so badly contaminated we know the dairy needs to make significant management changes to clean up their colostrum.

I am not willing to throw in the towel and accept badly contaminated colostrum as "normal." 

If you have an opinion about this feel free to contact me at

Reference: C. Cummins and Others, "The effect of colostrum storage conditions on dairy heifer calf serum immunoglobulin G concentration and preweaning health and growth rate." Journal of Dairy Science, 100:525-535 (January 2017).

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