Friday, March 6, 2015

Heat Treating Colostrum - Revisited

"The objective of this randomized clinical trial was to describe the effect on colostrum characteristics and passive transfer of IgG in neonatal calves when using the Perfect Udder colostrum management system ... compared with a negative control (fresh refrigerated or fresh frozen colostrum) and a positive control (batch heat-treated colostrum)."

 The colostrum was handled these ways:
1. heat-treated in Perfect Udder bags
2. heat-treated in a batch pasteurizer
3. fresh frozen
4. fresh refrigerated

The standards that I use to define upper levels of bacteria in "as-fed" colostrum are:
A. No more than 5,000 cfu/ml coliforms
B. No more than 50,000 cfu/ml total plate count

How did these samples compare to these standards?

   Sample (as-fed, warm)                       Coliform        Total Plate     My comment
                                                              (cfu/ml)         (cfu/ml)
1. heat-treated in Perfect Udder bags    3                    16,000             Okay to feed

2. heat-treated in a batch pasteurizer    10                    4,000              Okay to feed

3. fresh frozen in Perfect Udder bags    6,500              400,000           Marginal

4. fresh refrigerated, PU bags                65,000            3,000,000         Bacterial soup

Heat treating did not change the antibody concentration in the colostrum - all the samples tested between 77 to 80 grams per liter. We often use 50g/l as the dividing line between good and poor quality colostrum. These 59 pound calves received 4 quarts of this colostrum so their antibody intake was over 290 total grams at first feeding.

Efficiency of transfer of antibodies into the blood of the calves was higher for the heat-treated compared to the fresh colostrum.
                                                                   Efficiency of absorption
1. heat-treated in Perfect Udder bags                   37
2. heat-treated in a batch pasteurizer                   37
3. fresh frozen                                                      32
4. fresh refrigerated                                             32

Because all of the calves received well over 290 grams of antibodies in their first feeding that was between 77 and 88 minutes after birth, in spite of the high bacteria counts in the fresh colostrum that compromised antibody absorption, all the calves still had reasonably high immunity (blood serum total protein values above 6.5g/dL where 5.5g/dL is considered successful passive transfer). [Just for reference here our goal for first feeding is at least 200g/L of antibodies.]

These Jersey calves only averaged 59 pounds at birth. In this situation we might have advised the dairy to consider feeding 3 quarts rather than 4 quarts of colostrum to achieve adequate immunity.

For a fact sheet on heat-treating colostrum click HERE.

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