Bacteria Win Again
You start with a large, well-run dairy. Pool all the colostrum every day. Separate this into four batches each day.
#1 - batch heat-treatment at 140F for 60 minutes
#2 - heat-treatment in Perfect-Udder bags at 140F for 60 minutes
#3 - freeze fresh in same bags
#4 - refrigerate fresh in same bags
Then, get the colostrum ready to feed the calves (bring to calf body temperature) and take "as-fed" samples.
Culture the samples for bacteria to get (a) total plate count and (b) coliform count.
Average total plate counts (colony forming units/ml)
#1 batch heat-treated 4,000cfu/ml
#2 bag heat-treated 16,000cfu/ml
[Anything under 50,000cfu/ml is considered okay for feeding newborn calves.]
#3 Raw frozen/thawed bag around 500,000cfu/ml (bacteria soup)
#4 Raw refrigerated bag over 3,000,000cfu/ml (bacteria soup)
Average coliform counts
#1 batch heat-treated 13
#2 bag heat-treated 3
[Anything under 5,000cfu/ml is considered okay for feeding newborn calves.]
#3 Raw frozen/thawed bag 6,300cfu/ml (not good)
#4 Raw refrigerated bag 63,000cfu/ml (just plain awful)
I have not corresponded with the research time but I suspect that the colostrum was not chilled promptly post-harvest. Thus, bacteria grew rapidly before the refrigerated and frozen lots got cold enough to slow down the rate of multiplication.
A.A. Kryzer, S.M. Godden and R. Schell, " Effect of feeding colostrum that was heat-treated with Perfect Udder system on passive transfer of immunoglobulin G in neonatal Jersey calves." Proceedings of American Association of Bovine Practitioners, p 171, September 2013.