WildAgain Wildlife Rehabilitation, Inc.

(Excerpted from: Manufacturing Changes for Esbilac^® Powder Affect Wildlife Rehabilitators. 2010.

 Allan M. Casey, III and Shirley J. Casey, WildAgain Wildlife Rehabilitation, Inc., Evergreen, CO)          

or the Short Report (PDF .3 MB).

What does this mean for wildlife rehabilitators?

Should they use the Esbilac® powder differently?

Should they even continue to use Esbilac® powder?

Potential Impacts/Difficulties due to using the new Esbilac® powder

Rehabilitators who had used Esbilac® powder successfully for many years reported serious digestion issues when the formula made with the single-step spray-dry powder was fed to juvenile wild mammals. The questions addressed in this report and the tests performed suggest that many of the difficulties experienced by rehabilitators were a result of using the new Esbilac® powder as directed by the label.

These tests indicate that the product appears to have undergone some physical changes that affect its weight, compactibility and solubility. These issues, either individually or collectively, can produce a formula that is deficient in nutrients and/or energy. Mixed according to the label, the Esbilac® powder may not have been fully rehydrated and dissolved when fed – which could affect digestion, absorption, and utilization by juvenile wild mammals.

WildAgain believes that the reported gastrointestinal and other health problems are likely to continue unless wildlife rehabilitators change their preparation and use of the formula to accommodate these changes in the ‘new’ Esbilac® powder.

Feeding milk products that are inadequately rehydrated and dissolved can create digestive upset such as nausea, bloat and diarrhea. This upset is especially likely in younger and/or compromised animals that have a much less mature and robust digestive tract. They can easily develop more problems, including severe diarrhea, when fed inadequately dissolved milk products. In turn, diarrhea can cause inflamed and irritated gastrointestinal systems and dehydration. Infections reported earlier, such as the E.coli, Klebsiella p, and Salmonella could also easily develop – and become severe. Green diarrhea could be a sign of such infections.

Undigested milk products in gastrointestinal tracts of these juvenile wild mammals also are a great growth medium for bacteria. Since young mammals are fed frequently throughout the day, each feeding would only serve to exacerbate the problem. It would be easy for bacteria that would otherwise be at ‘normal’ low levels to multiply to create massive infections in multiple organs and systems.

It is difficult for animals to digest formula that is inadequately dissolved and that can compromise their ability to absorb and utilize adequate nutrition. The animals would be very hungry. Inadequate nutrition could also cause green diarrhea (‘starvation stools’). The animals would not gain weight adequately – and would have slow or no growth. They would weaken, as well as become susceptible to and have difficulty overcoming secondary infections. They also could develop a variety of disorders related to long-term diarrhea and poor nutrition, including prolapsed rectums, intestinal scarring, and metabolic bone disease.

Inadequately dissolved milk replacer powder could contribute to many if not all of the problems reported by the rehabilitators. In addition, the difference in mixing methods and supplements, fats and yogurt, could explain why some rehabilitators reported healthy animals and others saw many problems.

It is still certainly possible that there are additional factors in or related to the Esbilac® powder causing health problems in juvenile wild mammals.

Modified preparations for using the ‘new’ Esbilac® powder for juvenile wild mammals

Suggested preparation steps have been developed based on the positive reports of some rehabilitators who had previously had good results last year with the ‘new’ Esbilac®, WildAgain tests, and the results of rehabilitators feeding formula made with the ‘new’ Esbilac® powder to infant and juvenile tree squirrels in February and March 2010. The preparation ideas are provided in Appendix G.

As mentioned earlier in this report, the milk composition requirements of wild mammal species often require supplementing commercial milk replacers with additional products, such as fats. A short information sheet comparing cream with powdered fats (e.g., MultiMilk®) is provided on www.ewildagain.org

In addition, rehabilitators who added a small amount of yogurt to the formula before placing it in the refrigerator to ‘rest’ believed it made a very positive difference. Research on probiotics explains the benefits and reasons. A short handout on using probiotics, including yogurt, with formula made from milk replacers is available on www.ewildagain.org

Confirmation trials in process 

Several rehabilitators who reported serious gastrointestinal conditions after feeding formula made with the ‘new’ Esbilac® powder have recently changed their formula preparations as they began feeding neonate (‘pinkie’) and juvenile squirrels in February 2010. These rehabilitators, who are from several states, followed the methods used last year by colleagues who had reported positive results and incorporated the information from WildAgain’s research. An example of a revised mixing protocol is described in Appendix G.

The number of rehabilitators participating in the current confirmation trials using the revised mixing protocols for the ‘new’ Esbilac® powder has been very limited since wildlife baby season had just started as this report is being finalized. In general, they have reported positive results when following all the revised mixing protocols. Their squirrels, especially the ones with fur, seem to be healthy and growing at a faster rate than they did when fed formula made with ‘old’ Esbilac® powder. These rehabilitators did not see the diarrhea, dehydration, infections, slow growth and other problems they had seen in 2009 when following the instructions on labels of the ‘new’ Esbilac® powder and feeding it to juvenile wild mammals immediately after mixing.

Some rehabilitators using the revised mixing protocols for the ‘new’ Esbilac® powder saw great results with neonate and pinkie squirrels.  Those who followed all the revised mixing protocols, including the addition of extra fats (i.e., heavy whipping cream) and yogurt, reported that the infant squirrels grew very well and seemed healthy.

Rehabilitators who fed formula made with the ‘new’ Esbilac® powder, the revised mixing protocols, yogurt, but did not use extra fats reported different results. The good news was that the infant squirrels acted healthy and gained weight at almost double the rate that they did on formula made with the ‘old’ Esbilac® powder. However, the infant squirrels that did not have extra fats in the formula had soft to liquid stool, instead of formed and firm-textured feces. Their stool was also brighter yellow in color instead of the more normal dark gold color. These rehabilitators eliminated other possible problems (e.g., overfeeding, coccidia), tried adjusting the amount of yogurt, and so forth. In some cases, the stool of the infant squirrels achieved normal form and texture within two days of adding the extra fats. In other cases, the rehabilitators reported that the stool normalized within two days of being switched to another milk replacer. This suggests that the addition of a small amount of extra fats, such as heavy whipping cream, seems essential for squirrels of all ages and possibly for other species as well. The amount and type of extra fat needed to supplement formula made with the ‘new’ Esbilac® powder for various species deserves more attention and research.

These rehabilitators believed that a couple of observations were especially noteworthy. First, even though some of the infant squirrels that did not have the extra fats added to their formula had yellow diarrhea for several days, they gained weight at a faster rate than on formula made with the ‘old’ Esbilac® powder. And second, they did not develop gastrointestinal or other infections. The rehabilitators believed that the yogurt helped make the formula more digestible, improved digestion and access to nutrients - which contributed to the weight gain. Also, they believed that the yogurt performed as research suggested it would: it increased the number of ‘good’ bacteria and helped prevent the ‘bad’ bacteria from multiplying, and supported the immune system. 

Several other rehabilitators reported that a couple of the older juvenile squirrels had minor gastrointestinal upset. Closer examination suggested that some problems were related to more common conditions, such as coccidia, giardia and overfeeding – and not related to issues with the ‘new’ Esbilac® powder. 

While additional confirmation trials are still in process, the initial results suggest that the changes in preparation described in Appendix G seem to help prevent or reduce problems related to using the ‘new’ Esbilac® powder with juvenile squirrels - and will hopefully do the same for other wild mammals.

WildAgain believes it is essential to see consistent and repeatable positive results confirmed by rehabilitators who previously saw problems after feeding formula made with the ‘new’ Esbilac® powder before drawing conclusions. 

Additional research still needed

While WildAgain cannot yet provide conclusive answers or definitive recommendations, the authors are cautiously optimistic that the results of using the revised mixing protocols will be helpful for a variety of milk replacers made with the single-step spray-dry method that are fed to wildlife, including the new Esbilac® powder. WildAgain also believes that time, experience and further analysis will provide more comprehensive information and conclusions.

As in general practice, wildlife rehabilitators will need to consider and evaluate the information and make personal decisions as to their rehabilitation practices, including milk replacer selection, diet formulation, preparations and use.

Wildlife rehabilitators considering Esbilac® powder as a milk replacer base for juvenile mammals in their care need to know about the issues described in this report so they can make those informed decisions. The authors realize that some will choose Esbilac® powder for wildlife in rehabilitation, and others will not. If a rehabilitator chooses to use Esbilac® powder for wild mammals, we believe it is important to take these issues into account and adjust formula preparations accordingly: check for rancidity, turn the can over before measuring, use hotter water to mix, add extra fats and yogurt to the cooled formula, and then allow the mixed and cooled formula to rest in the refrigerator for at least 4 hours, and preferably a minimum of 8 hours.

If rehabilitators notice early signs of health problems (e.g., soft stool, bloat, slow growth), they should first try to eliminate the possibility of a common cause, such as overfeeding, diet change, or endoparasites. If those common causes of health problems are eliminated and the milk replacer is suspected to be the source of the problem, consider changing to another product that is appropriate for the species and age of the animal. Communications with other rehabilitators and the manufacturers will be essential to identifying the causes of health problems and solutions.

WildAgain and other rehabilitators are still working to more fully understand the causes of and solutions to the gastrointestinal and other problems of juvenile mammals being fed milk replacer formulas. Additional causes and solutions may be identified. We hope this research can support wildlife rehabilitators and the wild animals in their care. We also encourage rehabilitators and others to continue this research and even repeat the tests conducted by WildAgain as described in the this report.

Note: Communications with PetAg

In the fall of 2009, the authors had several productive phone conversations and emails with PetAg staff about concerns reported by rehabilitators who were feeding formula made with Esbilac® powder to juvenile wild mammals. We also talked about possible causes and solutions. We provided detailed information about the symptoms and how other common causes had been considered and eliminated. In return, PetAg shared non-proprietary information, such as that they had begun manufacturing the Esbilac® powder with the single-step spray-dry method instead of their former multi-step dry process, and confirmed that the powder weighed slightly less. They also provided suggestions such as turning the can over prior to measuring to more evenly distribute the powder, and using hot water for mixing, instead of warm.

PetAg emphasized that Esbilac® powder is developed for puppies and KMR® for kittens – and that any use with wildlife is considered ‘off-label.’ They recommended that rehabilitators use their Zoologic® Milk Matrix products even though they realized that many rehabilitators used Esbilac® and KMR® powdered milk replacers.

We believed those open and candid communications were helpful to rehabilitators and PetAg. We hoped they would lead to ways for rehabilitators to continue to use Esbilac® powder successfully with wildlife in rehabilitation, such as by developing simple modifications including some combination of changes in measuring, formula recipe and/or hydration time.

In January 2010, the authors sent an email asking if the PetAg technical staff could provide more information on their test results and ideas about what might have been causing problems with some wild animals fed formula made with the ‘new’ Esbilac® powder. They responded that they had not yet been able to isolate any changes that would be responsible for the problems.

As a result of those positive communications and hopes of finding workable solutions, the authors offered a preview of the test results in this article to PetAg management. PetAg has not accepted that offer prior to this report being finalized.

The authors have no affiliation with PetAg or any other milk replacer manufacturer. We continue to encourage wildlife rehabilitators to contact PetAg directly with any questions or comments about their products or use (www.PetAg.com).

Esbilac®, KMR®, GME®, Zoologic® Milk Matrix, and MultiMilk® are registered trademarks of PetAg Corporation, Hampshire, IL.

Copyright 2010. © WildAgain Wildlife Rehabilitation, Inc. All Rights Reserved unless otherwise stated.