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5 myths about feeding pasteurized waste milk

Tom Earleywine for Progressive Dairy Published on 31 October 2019

Let’s take everything you know about feeding pasteurized waste milk and set it aside for a moment. There’s a lot of information out there, and I think we can all agree, it’s good to take a step back sometimes and reevaluate.

To find the truth, we’ll get to the bottom of some common misconceptions about feeding pasteurized waste milk. We’ll bust some myths along the way and highlight research to help separate fact from fiction.



Here are five myths about pasteurized waste milk:

Myth 1: Feeding pasteurized waste milk is more cost-efficient than feeding milk replacer

Busted: Milk replacer is often considered a more expensive feeding choice compared to pasteurized waste milk. But if you factor in the cost of producing and pasteurizing waste milk with minimal or no return on investment, this myth gets busted quickly.

Waste milk is often thought of as a “free” source of nutrition for calves. In reality, it’s very expensive. While many farmers have a readily available supply, having enough waste milk to feed all your calves can indicate a larger issue. Ask yourself these three questions when evaluating your waste milk supply:

1. Do you have cow health issues that should be resolved?

2. Are you feeding calves enough nutrition? You may be underfeeding calves based on the available waste milk supply.


3. In order to maintain waste milk supply, are you holding on to high somatic cell count or less healthy cows that could be infecting or crowding out other cows, and thus should be culled?

With your waste milk supply in check, you may have to pull saleable milk from the bulk tank to feed calves – a direct hit to your milk cheque. If you do feed pasteurized waste milk, use a pasteurized milk balancer to fortify and provide consistent nutrition to your milk supply.

Myth 2: Pasteurizing kills 100% of the bacteria in waste milk

Busted: Pasteurizing is a great tool to help improve the quality of your waste milk. However, bacteria may still be lurking, even after pasteurization.

One study showed that 41% of on-farm pasteurizers failed to kill the necessary number of bacteria when tested immediately after pasteurizing. The other 59% of pasteurizers kept colony-forming units (CFUs) to less than or equal to 20,000. Pasteurized waste milk samples tested at the last calf fed showed even more bacteria were present at the end of feeding. For the last calf fed, 54% of pasteurized waste milk failed at over 20,000 CFUs.

The bottom line is, in many systems, bacteria will still be present after pasteurizing. Bacteria grow rapidly after pasteurization if milk isn’t stored properly. Milk management and proper cleaning and sanitation of equipment are critical but still may not eliminate all bacteria from waste milk.

Myth 3: Pasteurizing waste milk removes traces of antibiotics

Busted: Growing concern about antibiotics in whole milk may give you some pause if you’re deciding whether to feed pasteurized waste milk. Antibiotics are not affected by the pasteurization process, and calves may develop some antibiotic resistance as a result of feeding pasteurized waste milk with antibiotic traces.


One multifarm study showed 56.8% of pasteurized waste milk contained traces of antibiotics. Many factors can impact antibiotic resistance in calves. However, the same study showed an increase in antibiotic resistance in calves fed pasteurized waste milk compared to calves fed milk replacer.

Myth 4: Pasteurized waste milk provides all the necessary nutrients calves need

Busted: One of the key benefits of feeding milk replacer is the certainty of feeding calves a nutritionally balanced diet. Pasteurized waste milk is often nutritionally deficient, lacking nutrients necessary for optimal calf growth and development.

Pasteurized waste milk consists of approximately 30% fat and 25% protein. Research showed pre-weaned calves grow more efficiently when their liquid diet contains a higher percentage of protein than fat. Pasteurized waste milk also lacks vitamins D3 and E, all seven essential trace minerals and five of eight essential B vitamins.

A pasteurized milk balancer can help address nutrient deficiencies by providing added vitamins and minerals, and correcting the fat-protein balance. Studies showed calves fed pasteurized whole milk and supplemented with pasteurized milk balancer gained 17% more weight from birth to weaning compared to calves solely receiving pasteurized waste milk.

Myth 5: Pasteurized waste milk provides consistent nutrition for calves

Busted: Nutritional consistency is critical for healthy, well-grown calves. But day to day and calf to calf, pasteurized waste milk total solids, fat and protein can be inconsistent. In fact, research showed that pasteurized waste milk from a single farm can vary as much as 6.58% in total solids, 7.9% in protein and 17.3% in fat.

A few culprits for pasteurized waste milk’s inconsistency include:

  • Source: Waste milk is often a combination of transition milk from recently fresh cows and milk from treated cows. Waste milk composition can vary greatly depending on the ratio of transition cow milk to sick cow milk.
  • Inconsistent handling: Improper agitation, inadequate cleaning and sanitation of feeding equipment, and incomplete pasteurization can lead to variable nutrition.
  • Human error: Nobody’s perfect. Occasionally, wash water may enter the waste milk supply or pasteurized milk isn’t stored properly.

A pasteurized milk balancer can help correct variations in solids that naturally occur in waste milk.

Truth: Select a feeding system that works for you

In this article, I’ve discussed several myths around feeding pasteurized waste milk, but the truth is – feeding pasteurized waste milk can be a good source of nutrition for calves, when fed correctly.
1119ca earleywine calf

If you choose to go the route of pasteurized waste milk, consider using a pasteurized milk balancer. A balancer can help extend milk supply and address nutritional inconsistencies. A laser focus on cleaning and sanitation, as well as proper milk storage and handling, will also help you make the most of your pasteurized milk feeding program.  end mark

References omitted but are available upon request. Click here to email an editor.

PHOTO: A pasteurized milk balancer can help improve the nutrition provided to your calves. Photo courtesy of Land O’Lakes.

ILLUSTRATION: Illustration by Kristen Phillips

Tom Earleywine
  • Tom Earleywine

  • Director of Nutritional Services
  • Land O’Lakes Animal Milk Solutions
  • Email Tom Earleywine