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Considerations for managing whole or waste milk with replacement heifers

Kayla Aragona, Tana Dennis and Mark Hill for Progressive Dairy Published on 11 March 2020

Raising replacement heifers is the second-greatest cost on a dairy farm, and these animals will dictate the future success of the enterprise. To ensure future productive success, many considerations should be evaluated in terms of the liquid diet fed to young pre-weaned calves, especially when the liquid diet consists of whole or waste milk.

Popularity of feeding whole or waste milk tends to increase during tough financial times, specifically when the milk price drops. However, the consistency and quality of waste milk can vary greatly and does not meet National Research Council (NRC) requirements for vitamins and trace minerals for young calves (Table 1).



Concentration of essential vitamins and trace minerals in milk replacer compared to whole milk

Typically, whole milk is 12% to 13% solids while waste milk can vary day-to-day depending on the proportion of colostrum or transition milk present. A trial we conducted at the Nurture Research Center found that dry matter, crude protein (CP) and fat of raw milk fed to calves varied by 43%, 6% and 10%, respectively. This variation in nutrients supplied to calves from raw milk resulted in decreases in average daily gain (ADG), feed efficiency and hip-width gain compared to calves fed a consistent milk replacer diet. A disproportionate number of one-breed or crossbreds freshening at a given time can also impact waste milk solids percentage.

In many situations, the supply of waste milk is highly variable, therefore milk replacer, balancers or other milk powders are often used to extend or fortify the supply. This can result in instances where the liquid diet has a high percentage of solids. A major concern when large amounts of powders are used to extend the supply of waste milk is inadvertently feeding a liquid diet with high osmolality. Osmolality refers to the concentration of dissolved particles in a solution and is reported as milliosmoles (mOsm) per kilogram of water.

Osmolality increases significantly as solids content increases from additional powders. These added powders can be high in sodium and other minerals – electrolytes, for example – that increase osmolality. Typically, if osmolality increases above 600 mOsm per kilogram, abomasal emptying will slow, and water will be drawn into the digestive tract to dilute the liquid. As retention time of the liquid increases, risk for bacterial growth, including those producing gas and toxins, is much greater. This can lead to abomasal bloat, water imbalance issues and diarrhea.

Although osmolality is not typically measured on the farm, it is important to understand the concept, considering it can negatively impact calf health and performance. Many additives exist that can be added to milk or waste milk that can also potentially impact percent solids and osmolality. These items include:


  • Coccidiosis control products: Coccidiosis is a common problem in calves, and products like decoquinate and lasalocid are FDA-approved to go in milk for control.

  • Fly control products: Diflubenzuron, an EPA-approved product, can be used during warm months in integrated pest management programs to help control fly numbers.

  • Vitamins and trace minerals: Many are lower in milk than NRC published requirements, especially when feeding for higher growth rates.

  • Direct-fed microbials, pre- and probiotics, essential oils: Many products exist, but many have limited and sometimes inconsistent research data in calves.

  • Essential amino acids: Much published research show both improved growth and health when specific amino acids are added to milk replacer diet of calves less than 2 months old.

  • Essential fatty acids: Much published research show both improved growth and health when added to the diet of calves less than 5 months old.

At the Nurture Research Center, we have conducted trials to determine how specific, functional fatty acid addition to milk powder impacts calf performance. Pre-weaned calves were fed 1.5 pounds of whole milk powder with or without 25 grams of a fortifier that contained specific, functional fatty acids plus vitamins and trace minerals in Trial 1 and only the fatty acids in Trial 2. Figure 1 shows results from the two trials.

Impact of fortifying fatty acids to milk solids on claf growth

In Trial 1, the addition of the fortifier to milk powder increased ADG by 17%, feed efficiency by 8% and hip-width change by 21%, and decreased abnormal fecal days by 50% and medical days by 17%. In Trial 2, addition of fatty acids increased ADG by 18%, feed efficiency by 21% and hip-width change by 18%, and decreased medical days by 63%.

In summary, it can be beneficial to supplement whole or waste milk fed to calves to improve performance, such as functional fatty acid, as demonstrated in our research. However, considerations need to be made to ensure solids percent, and consequently osmolality, does not reach a level that can negatively impact calf health and performance. If you’d like to learn more about osmolality, or discuss different impact of additives in whole or waste milk, consult your nutritionist or a calf and heifer specialist.

Regardless of what is being added to milk, emphasis should always be placed on proper pasteurization of milk to control pathogens. All calf programs need to focus on proper hygiene, including cleaning and sanitation of equipment, to aid in preventing contamination to help ensure calf health and growth.

Take-home points

1. Consistency and quality of whole or waste milk varies day-to-day. Controlled research found that an inconsistent supply of nutrients reduced calf growth.


2. Different types of products, such as balancers or other milk powders, are available to extend or fortify supplies of whole or waste milk. However, these powders can inadvertently increase osmolality of the diet, potentially leading to abomasal bloat and diarrhea.

3. Specific, functional fatty acid addition to milk has improved calf growth and health in controlled research.

4. Consult with your nutritionist or a dairy calf and heifer specialist to learn more about osmolality and managing whole or waste milk with young calves.  end mark

Kayla Aragona, Ph.D., is a dairy calf and heifer specialist with Provimi. Tana Dennis, Ph.D., is a calf and heifer technical support specialist with Provimi. Mark Hill, Ph.D., is a ruminant nutritionist with Provimi.

Kayla Aragona
  • Kayla Aragona

  • Calf and Heifer Specialist
  • Provimi
  • Email Kayla Aragona