Ask the Expert: How Does Waste Milk Compare? – Dr. Steve Hayes, Day 1 Technology

Q:  How does my waste milk compare to the bulk tank milk I sell when it comes to feeding calves?

A:  This is a great question since so many calf raisers are using some or all waste milk to feed their calves today. One may think that waste milk is similar to what’s sold from the bulk tank, but there are many real differences.

To begin the discussion, let us define exactly what waste milk is. Most people define “waste milk” or “hospital milk” as the milk that comes from their cows but is not put into the bulk tank for sale. The milk we are talking about is from fresh cows (transitional milk), mastitis cows, treated cows within the antibiotic withdrawal period, or high somatic cell count cows.

Transitional milk has definite differences in solids, protein and fat when compared to the others. With that in mind, you need to evaluate what cows are actually contributing to the waste milk supply since it will be fed to your future herd.

The biggest quality factor to monitor in your waste milk is the total solids level. Most saleable milk will be around 12 to 12.5 percent solids. This is easily measured using a Brix refractometer. Place a drop of milk on the device and note the reading.  It usually works to add 2 to the reading to calculate your solids level.  For example, if you get a reading of 10 on the Brix, your solids level is usually going to be a 12 when reading milk samples.

In my experience, it is very common for waste milk to have levels less than 10, indicating the solids level in waste milk is less than in whole milk for sale.  That’s a result of letting the water from cleaning and flushing the milk lines run into the waste milk collection tank.

That’s why it’s important to develop and monitor waste milk protocols.  Keeping solid levels constant from one feeding to the next is very important for calf growth and calf health. As such, run a Brix reading with every waste milk feeding.

Another important factor to monitor when feeding waste milk is the protein and fat. This can vary significantly depending on the number of fresh cows putting milk in the tank.  It is pretty simple to pull a sample periodically to make sure you know what the protein and fat levels are when feeding your waste milk. This will allow you to determine if your nutrition program is on track or needs to be changed. Your local milk plant should be able to run these samples for you.

The last concept to discuss is the presence of antibiotics in waste milk. The most important thing to know is that you could have antibiotic residues in your calves being fed waste milk. For most replacement heifer operations, this is not a concern. Bull calves fed waste milk and then sold could potentially enter the food chain and residues could be found. Be aware of this possibility.

Include the following three steps in your waste milk action plan:

1. Use a Brix refractometer to monitor the solids level of waste milk fed to calves. Do this daily and record the results. If it fluctuates, work with the hospital string milkers to minimize any variation in water getting into the hospital tank. Calves need consistent nutrition and a steady solids number to perform well and stay healthy.
2. Send samples of the waste milk from several feedings to a laboratory to analyze for protein and fat levels. How do these compare to your regular saleable milk? Do they vary? Do this at least monthly for three months or more.
3. Monitor the data on a regular basis (weekly to monthly) and make protocol changes accordingly.

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