DAIRY

Colostrum Chilling
In the first place, if we are going to feed colostrum within thirty minutes after it is collected, why
would we want to chill it? Obviously, the answer is that it does not need chilling. Just feed it
promptly.
Why chilling?
We want to feed clean colostrum. Our goal is to reduce the bacterial load in colostrum in order
to promote good gut health. Clearly it makes sense to avoid bacterial inoculation of colostrum
as a first step toward this goal. That means clean teats in the parlor. In addition, we need to
start with clean collection, feeding and storage equipment.
In many cases not all our colostrum is going to be fed directly from the dam. If it is going to be
held more than one-half hour the colostrum is at risk of growing bacteria. Colostrum is very
good bacterial growth medium – favorable pH and lots of readily available nutrients. Also,
when collected from a cow it is at an excellent temperature to encourage bacterial growth. By
the way, we describe these growth rates using the term “Generation Time.”
One way to slow down the rate at which bacteria multiply is to lower the temperature of the
growth medium – colostrum. For example, when we reduce colostrum temperature from 95 to
60 degrees, coliform generation times increase from roughly 20 to 150 minutes. Thus, if we
want to cut down bacteria numbers that come from initial inoculation one alternative is to rapid
chill the colostrum to at least 60 degrees.
Farm-friendly ways to Chill
In order to be “farm-friendly” a chilling method has to be simple and cost effective. One such
method is a water bath. Colostrum is transferred into containers smaller than milker pails or
five-gallon pails. Most folks use calf nursing bottles. Others buy two or four quart plastic
containers. Unless the containers are one-use disposable ones make sure that it is easy to
brush all the inside surfaces.
Right-size the tub for the water bath based on your experience with colostrum volume. Larger
farms may consider using several water bath containers for increased flexibility. Remember
that for most efficient heat transfer at least ¾ of the container needs to be submersed in the
ice-cold water. And, just packing ice around the containers without water is not an efficient
method of chilling.
June 2008
By Sam Leadley of Attica Veterinary Associates
Very large operations should consider purchasing a used restaurant ice maker. Smaller dairies
find it practical to use the freezer compartments of refrigerators or a small chest freezer for
making ice. Several of my clients repeatedly freeze “cold-packs” rather than use water for
making ice.
Another “farm-friendly” method is adding containers of ice directly to the warm colostrum. An
ice:colostrum ratio that works well to chill just-collected colostrum to 60 degrees within one-half
hour is 1 quart of ice to 1 gallon of colostrum. In general multiple small ice containers will do a
better job of chilling compared to one larger container. For example, six 16 ounce recycled
plastic soft drink bottles compared to one one-gallon plastic jug.
A few dairies place the equivalent of 3 quarts of ice in the stainless steel milker bucket before
milking the fresh cow. This procedure eliminates errors in remembering to add ice once the
fresh cow is milked. Other dairies with more than a few quarts of colostrum to chill pour 3
gallons of colostrum into a five-gallon pail, add a one-gallon jug of ice, put a lid on the pail and
put the entire pail-jug-colostrum into a refrigerator. The colostrum chills from the inside-out as
well as from the outside-in.
One caution! When containers are placed directly into colostrum they need to have as few
bacteria on their surfaces as is practical. Just rinsing them quickly with tap water as they are
transferred from the freezer into the colostrum is a best management practice. If these
containers are used more than once someone needs to be given the responsibility of cleaning
these each time they are cycled through the freezer. Remember to avoid colostrum build-up
underneath the caps on these bottles and jugs.
• Many dairies have one person responsible for handling colostrum. In order to both
rapidly chill colostrum and keep it cold until that person is available some farms extend
chilling. That is, after placing ice containers directly into colostrum for initial chilling the
night shift workers simply replace the first batch of ice bottles with a fresh set as they
leave. Or, additional ice is added to the ice bath to carry the colostrum over until the
colostrum person is available. If an ice bath container is right-sized to fit into a
refrigerator that solves the cooling problem. Another dairy immediately after harvesting
colostrum places a one-gallon jug of ice in each milker bucket and they go into a chest
freezer to wait for processing. – are they working?
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