WildAgain’s next round of research and analysis on powdered milk replacers



Wildlife rehabilitators know that diet and nutrition are critical to the health, well-being, survival and ultimate release of animals in rehabilitation. As it says in the NWRA Principles of Wildlife Rehabilitation (2nd edition):

That statement is as true today as it was when published over 18 years ago – perhaps more so. Nutrition matters.


Compelled by recent reports from rehabilitators from around the country about unexpected health issues observed in young nursing mammals, we at WildAgain have committed to updating and expanding upon the research that we conducted 10 years ago. This includes looking at the variety on powdered milk replacers widely used; how they are chosen and mixed to construct milk formulas fed to young mammals; and working to identify any possible links between the reported health issues and these products and formula recipes.


WildAgain is working to provide a variety of resources to support the rehabilitation community exploring this large, complex and developing topic. As our current research and analysis begin to reveal trends or concerns/issues, the information will be available in short articles, as well as longer papers, training videos, presentations, and more. Most will be available here at ewildagain.org



Here is a list of the areas of research exploration and analysis, as well as some of the initial information we plan to produce and share (targeted for release January and February 2020):


1) An extensive review and update of the primary milk replacer products used widely by rehabilitators. Over 90 lots from various products have been submitted to a certified lab for analysis as to protein and fat content, as well as content levels for primary dietary minerals such as calcium and phosphorus, and trace minerals such as copper, iron and manganese.


2) Since we have longitudinal data spanning 15 years, we are able to examine multi-year trends in product ingredient changes and nutrient levels.



3) A continuation of earlier tests on some of the physical handling characteristics of the products, such as potential measurement inconsistencies and errors caused by scooping powder rather than weighing. A much more thorough examination into the hydration and solubility efficiencies of the products compares different water temperatures and length of hydration time.


4) Information on the mammal milk composition analyses by species; reasons to consider them and the information they provide; and readily available sources for them.


5) A new version of the WildAgain nutrition calculator (version 3.0) with updated data on over 150 lots from various products, and including a new and improved layout and added functionality. Typical nutritional analyses from common milk replacers from several manufacturers are provided, including proteins, fats, kcals, Calcium and Phosphorus amounts and ratios, and more. The calculator allows the user to compare products and recipes to best match mother’s milk of various species. (Downloadable Excel workbook.)


6) A discussion of several formula recipes for different species compare to the mother’s milk for the species using the nutrition calculator. While the math comparing to the mother’s milk is important, it is also essential to consider how the formula recipes work with the species and individual animal, the animal’s health and age, preparation and mixing methods, feeding methods, amounts fed and frequency, and the milk powders.


7) Ways that product handling and formula preparation affects the formula’s ability to deliver the expected nutrition – and how to improve the solubility, and then digestibility. This includes some steps to help guide the preparation of formula using the product info and research. For example, if you use heavy whipping cream as a fat supplement, at what point in mixing formula do you add it?


8) General considerations for use selecting products, recipes and preparation methods for use in 2020 and beyond.


9) Reported health conditions in juvenile wild mammals that prompted the research (2019) – focusing on squirrels, opossums and raccoons. Examining factors that may have contributed to those nutritional problems. Still collecting data on cases from phone interviews, surveys, and reports.


10) WildAgain will discuss factors considered when making decisions and evaluating products and recipes, but not recommend particular products or recipes.

“Nutritional mismanagement is second only to trauma as a cause of death or progression to unreleaseable status of wildlife….”.

Mammal rehabilitators intuitively know that nutrition for nursing young is complicated, as it involves selecting products or formula recipe for a species, then considering age animal, health condition, product variations and changes, and so much more.  They also know that many things can influence their feeding practices and formula decisions – ranging from coaching from one or more mentors, publications, continuing education, experiences (successes and problems), websites, personal preferences, and the myriad of social media postings.

We encourage you to use your best critical thinking when evaluating any and all of that information (including from this website!). Ask lots of questions as to reasons and sources of information. Exercise caution and diligence as to the nutritional choices and care you provide to the animals in your care. Their lives literally depend on it.

And thanks to the many rehabilitators who have shared information, donated milk powders for testing, been part of the research team, and work so hard for wildlife and people concerned about wildlife.



Available Now!

1) Click here to download the spreadsheet.


2) Read and keep the product labels and lot numbers.


Available Now!

3) Click here to review the test results.




Available Now!

5) Click here to go to the Calculator. Get the free download.




6) Examples of how to formulate a workable recipe using the calculator.


7) Does it matter when you add cream or other ingredients?



8) How to read and understand the label on a bag or can or powder. Factors that may have contributed to the nutritional problems.


Photo credit: Shirley Casey


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