Choosing the right type of milk to feed your calves

Choosing to feed calves whole milk or milk replacer is a big decision, as it can have an impact on lifelong performance.  Let’s consider some pros and cons of each type of milk.

Salable milk

In Canada, feeding salable whole milk to calves is often a method to expend milk produced over available quota. Whole milk typically contains between 24 and 27 percent protein and 28 to 36 percent fat on a dry matter basis. Calves typically perform well on clean, salable milk. This milk should be collected and stored as if it was milk intended for sale (i.e. sanitary collection, storage and refrigeration) and pasteurization is recommended to reduce the risk of transmitting pathogens. As whole milk composition can fluctuate over time (such as total solids, protein, and fat), it may sometimes cause digestive upsets in calves or provide them an insufficient amount of energy.   A Brix refractometer can be used to evaluate the consistency of total solids. Further, pasteurization must be done carefully and accurately to reduce bacteria loads without degrading the nutrient quality of the milk. A drawback of feeding salable milk is that it can be difficult to consistently produce enough milk over quota to feed calves, and feeding calves milk that could be sold is not a cost-effective strategy.

Waste milk

A 2010 study, conducted by Vasseur et al, of dairy farms in Quebec found that unpasteurized waste milk from cows treated with antibiotics was fed to calves on nearly half of the farms surveyed. Although feeding waste milk may seem to be a viable economic strategy, it carries with it substantial risks to calf health and is not recommended.  This is due to the risk of transmission of infectious pathogens, such as those that cause mastitis, or drug residues to calves. Antibiotics in milk have the potential to damage the gut flora (healthy gut bacteria needed for proper digestion) of calves and may contribute to growing antibiotic resistance, ultimately making antibiotics less effective. This may decrease future productivity of calves. Further, drug residues may be a concern if a calf is slaughtered shortly after drinking waste milk.  Some producers don’t realize that the young bull calves they sent to the sale barn may end up going directly for slaughter.  All carcasses from these calves are tested for antibiotic residues.   If a calf from your farm is found to have drug residues it is considered a serious food safety violation and government inspectors will follow up with you to determine how the violation occurred.

If waste milk is fed, it should always be properly pasteurized to reduce the risk of pathogen transmission. Further, it should be noted that the day to day variability in composition of waste milk may increase the risk of digestive upsets. Feeding waste milk could save on the cost of feeding calves, but may increase treatment costs and hinder future health and production.

Milk replacer


There is a great deal of fluctuation in the prices of milk replacers. This variation is often due to differences in ingredient quality or changes to the ingredient list. However, the composition of a specific milk replacer, if used consistently, will be much less variable than either salable or waste milk. Despite this, it is still recommended you mix new batches of milk replacer with the old batch to ensure any differences in composition do not cause problems for the calves. See Calf Care’s “The 5 Cs” for details on how to transition between batches of milk replacer.

Although milk replacer is more expensive than the opportunity cost of using waste milk, it offers a more consistent product and enhances biosecurity and food safety by preventing the transmission of pathogens and drug residues from cows to calves. Calves thrive on consistency.

A traditional milk replacer will contain 20 to 22 percent protein and 10 to 25 percent crude fat on a dry matter basis as well as a variety of key nutrients and minerals. However, milk replacer allows you to customize nutrition to the needs of your calves at various points in their growing period or based on climatic conditions. For example, you can supplement calves with specific nutrients, such as selenium, or you can use a milk replacer with a higher percentage of crude fat in cold weather.

Medicated milk replacers are controversial due to growing concerns surrounding antibiotic resistance. Research is ongoing to determine if other additives to milk replacer, such as probiotics, can improve calf health and growth while reducing the use of antibiotics. Some medicated milk replacers also contain additives to prevent parasitic infections, such as coccidiosis, which can improve calf health and performance. Producers must be aware of the required meat withdrawal times for medications in milk replacer, especially for calves that are sold. Producers must weigh the risks and benefits of added medications.  Discuss the need for medicated milk replacer with your herd veterinarian.

It is important to note that you need to match your milk replacer to your feeding program and growth targets. Simply doubling the amount of conventional milk replacer (20 to 22 percent protein) fed will not increase growth of lean tissue (muscle), and the extra energy in the diet will be converted into fat. In contrast, feeding around four litres per day of an “accelerated growth” high protein milk replacer (26 to 28 percent protein) designed to be fed at higher levels (approximately double conventional levels) will not allow calves to grow because they are not being provided enough energy to support increased growth. If your milk replacer does not align with your feeding program, you may end up spending more but not seeing the results you expect.

The best milk replacer for your herd will depend on many factors, including calf age, feeding program, management, and growth targets. For more information on choosing a milk replacer, see Calf Care’s “Evaluating Milk Replacer” and talk to your herd nutritionist.

Acidified milk or milk replacer

Acid can be added to unrefrigerated milk or milk replacer to slow bacterial growth, but acid does not kill bacteria already present. Your herd nutritionist can advise you on finding an ideal pH, which is typically between 4.0 and 4.5. It is best to test the pH each time you mix milk replacer, rather than just adding a standard amount of acid. This helps ensure you are reaching an effective pH and provides consistency for your calves. Adding acid does not change the nutritive value or impact performance of the calves but allows larger amounts of milk or prepared milk replacer to be offered at once while inhibiting bacterial growth. If milk or milk replacer is consumed quickly after being offered, there is little benefit to acidifying it. For example, if calves are bottle fed and drink their entire meal shortly after it is offered or you use an automatic feeder that mixes milk on demand, there is no reason to acidify the milk or milk replacer. However, if milk is left unrefrigerated over several hours, such as a milk line system, acidifying it can help protect calves from disease caused by bacteria growth.

Some milk replacers are acidified during manufacturing, saving you the time it takes to acidify milk replacer yourself. Mark Bowman, Ruminant Nutritionist with Grand Valley Fortifiers says “The pH found in acidified milk replacers will be influenced by the water that the milk replacer is mixed into, so it will vary from farm to farm. However, in general the pH range will be 5.2 to 5.7 for these products.” Milk replacers that have a pH higher than 4.5 may not be suited to being left unrefrigerated for long periods, so be sure to check the pH of premixed products and ensure it is the appropriate level for your system.


Combinations of excess salable milk and milk replacer may be fed, but carry the risk of inconsistent composition, leading to digestive upset. Making feeding changes slowly, over a period of several days, may assist in minimizing this concern.

Monitoring growth

The best way to ensure your feeding program is profitable is by monitoring the growth of your calves. A simple and inexpensive method of monitoring growth is using a weight tape. Work with your herd veterinarian or nutritionist to establish a weight monitoring program and growth targets for your calves. Typically this will involve measuring calves once a month. Farms with many calves can measure a subset of animals. By measuring calves and comparing performance to targets, you can further refine your milk feeding program to ensure calves are reaching to their maximum potential.


Talk to your herd nutritionist if you’re thinking about making changes to your calf feeding program. There is no “one size fits all” solution for milk feeding calves. Due to the huge variation in milk and milk replacer quality and different management systems, no one type is always better for every situation. It is important to evaluate the quality of the milk or milk replacer you are using and judge how well your calves are doing. Regardless of which recommended choice you make for your calves they should grow well, be healthy and they should not be hungry.  Remember, feeding calves is an investment, not just an expense.