Acidifying Milk and Milk Replacer

Adding acid to your kid goat’s milk? Sounds crazy right? It may surprise you, but acidifying milk for your goat kids actually has a number of health benefits for your kids! 

What are the benefits to acidifying milk?

There are several benefits to acidifying milk:

1. To slow the growth of bacteria in milk.  Milk provides an excellent environment for bacterial growth. When the rate of bacteria growth is slowed it reduces the kid’s exposure to bacteria, thus reducing disease risk.  Neil G. Anderson, DVM, MSc of the Ontario Ministry of Agriculture and Rural Affairs used a standardized plate-loop-count to study bacterial growth in both acidified and non-acidified milk. He found that the cultures for milk acidified at a pH of 4.3 had no bacterial growth after several hours. In the samples of untreated milk, the bacterial colonies quickly became too numerous to count over the same time frame.  When milk is acidified to a level of 4.2 it is an effective means of eliminating the growth of such bacteria as E. Coli, Listeria, Mycobacterium, Salmonella, Strep and Staph.
2. To preserve milk. Acidifying milk that is fed to the kids allows milk to be stored at room temperature for a longer period of time before spoiling.
3. Maintain steady pH level in the Abomasum. The normal pH level of the abomasum is very low, around 1 or 2. When the kid goat drinks non-acidified milk, the pH in the abomasum rises to the level of the milk, usually 6 or 7. As the milk is digested the pH level in the abomasum gradually lowers to its normal level. If you were to chart these variations it would look similar to the graph below:

By acidifying milk to a pH level of 4.2 the pH level in the abomasum does not fluctuate as it does with non-acidified milk. The highest pH level in the abomasum is now 4.2 instead of 6. This allows the pH level to return to normal much faster than with non-acidified milk. See the chart below:

What Acids Can be Used when Acidifying Milk?

There are a few types of acids that may be used for acidifying milk and milk replacer. Formic acid is an option and is used by many producers. However, since formic acid comes in a concentrated liquid it can be very dangerous, as any contact with the liquid or vapours can cause rapid skin irritation or severe damage to the eyes.

Citric acid (available on Amazon) is another option and is also a great choice for acidifying milk, as it is generally considered safe and is also approved for use in organic dairy production. Citric acid is available in powdered form which makes it easier to handle than a caustic liquid. Although it is easier to handle, care must still be taken when handling as citric acid dust can irritate the eyes, mouth and throat. Because citric acid comes in a powder it must be stored in an air tight container in order to prevent the absorption of moisture.

How much Citric Acid is Needed?

It is recommended that a pH tester be used in order to obtain an accurate mixture but a general guideline is to add 5g of citric acid per liter of milk replacer mixed at 150g/liter of water. At this inclusion rate, a pH level of 4.4 can be achieved. If feeding whole milk, citric acid can be added at a rate if 5.8 g/liter of milk.

References: 

1. Rob Costello, Effect of Acidified Milk Replacer on the Calf’s Digestive Tract.  Calf Sessions
2. Feeding Acidified Milk to Calves. Penn State Extension
3. Paisley Canning, Taryn McIntyre, Neil Anderson, Acidifying Whole Milk and Milk Replacer with Citric Acid. Ceptor Animal Health News. Volume 17, Issue No. 3, September 2009  — ISSN1488-8572
   
4. Neil G. Anderson, Experiences with Free-access Acidified-milk Feeding in Ontario. OMAFRA (Ontario Ministry of Agriculture, Food and Rural Affairs)