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New GME® (2022) - Part 1. How has it changed?

Long term users of PetAg®'s Goats Milk Esbilac® (GME) have seen labels come and go. PetAg®'s GME® has a new label featuring a light tan colored puppy since early 2022. The label discloses a newly formulated list of ingredients. WildAgain had various lab tests conducted, as well as performed reconstitution tests. This article (Part 1) discusses those results. Part 2 discusses and offers suggestions on what these changes mean.   

GME label history.jpg


It is understood that companies periodically change products to include improvements from new research, manufacturing methods and other factors (e.g., ingredient quality, shelf-life enhancements, etc.). Wildlife rehabilitators purchasing a new GME® (2022) may be hesitant and wary after issues from previous PetAg® changes

Part 1. This analysis provides the chemical analysis of the new GME® formulation and some of its primary formula preparation performance characteristics such as measurement and reconstitution. It does not assess how the new product will perform when fed to orphaned wildlife in rehabilitation, though some of the information certainly can be used with decisions and use. 

Part 2. An accompanying article (PDF) discusses some of these more significant changes and offers some suggestions that wildlife rehabilitators may consider when deciding what these product changes mean and how they may affect feeding young wild mammals.

The following list highlights some of the key findings prior to a more detailed presentation of test results and analysis. 

√ Ingredients. Many listed ingredients are the same, though likely in different concentrations or amounts. Dried corn syrup has been newly added, as has guar gum, fructooligosaccharide and powdered cellulose (fiber).

√ Proximate analysis. Protein has decreased 2% and remains below the guaranteed minimum of 33%; fat has increased 9% to the guaranteed minimum of 40%; now has 0.7% crude fiber (previously none); and a 19% decrease in calculated carbohydrates (NFE).

√ Ash. Chronically very light on dietary minerals, the new formulation shows a further 9% decrease overall, as well as individual decreases in all macro mineral concentrations and increases in all micro mineral concentrations. Calcium, at only 0.82%, remains below the generally accepted 1.00% concentration threshold.

√ Fatty Acids. The profile shows a 27% increase in polyunsaturated fats (a 26% increase in Linoleic acid (C18:1 Cis) alone), and a 25% decrease in overall saturated fats.

√ Rancidity. GME® continues to demonstrate worrisome low levels of shelf-stability characteristics. The 2022 samples tested at PV of 39 to 230 at 7 - 18 months since manufacture which are well above established guidelines for edible oils. Proper storage remains critical to slow further rancidification once the package has been opened.


√ Physical characteristics. Powder is still loose, fluffy and sticky. Measuring powder by volume or parts rather than weighing continues to cause error rates of + / - 5 to 17% from the calculated average weight. The average weight of the powder is trending slightly heavier over the last 15 years (≈ +2% per year on average). Additionally, both large and small artifacts were found in the dry powder which could be a result of quality control issues or using less than finely micronized ingredients, or both. 


√ Reconstitution (wetting and sinking). Very good performance when correctly adding powder to warm water, with test samples fully submerged in <30 seconds. 

√ Reconstitution (dispersal and dissolution). An 8-hour resting period from preparation (mixing) to final use (feeding) improves final reconstitution by 96%. Without the rest period and quickly prepared for an instant use/feeding, about 23.8% of powder remains dry and not fully reconstituted.

Ingredients (as listed on the package label)


The following table lists a side-by-side comparison of the ingredients of the pre-2022 and the new 2022 formulations. The notable 2022 change in the Primary Ingredients listing is the addition of dried corn syrup. All other ingredients are the same but the change in order listed suggests concentrations or amounts have likely changed. 

The list of Secondary Ingredients shows many small-quantity additives and supplements have changed in their presence/absence and likely concentrations. Guar gum, fructooligosaccharides and powdered cellulose are new ingredients presumably intended for prebiotic benefits that are essential for digestion, development, and the immune system. 

The fermentation products, previously not included, have been added presumably for probiotic benefits. 

GME 2022 Ingredient list.jpg

Proximate analysis

The following table shows the results of the proximate analysis performed by the lab as compared to the Guaranteed Analysis (max/mins). The red shaded values indicate where the lab analysis determined that the component concentrations failed to adhere to the maximum or minimum guarantees. Most of those outside guaranteed limits are minor and within lab testing tolerances, except for crude fiber which is 40% over the guarantee. 

Moisture now exceeds the maximum guarantee of 5%, up over 80% from the pre-2022 sample. This results in a lower percent of overall total solids in the new formulation. Also notable is the out-of-spec value in protein concentration, even lower than the prior sample. Due to the 9% increase in fat content of the new formulation, the metabolizable energy content (ME Kcals) equals 5.65 per gram of dry powder. That is a slight 3.1% increase over the previous sample of 5.48 Kcals/gr. Crude fiber now tests at 0.7% likely due to the addition of the prebiotics. These changes in the proximate values may require adjustments to previously used formula recipes, which can be easily calculated with the Wildlife Formula Calculator

GME 2022 Proximate Analysis.jpg

Ash (dietary minerals)

The following table shows the results of the dietary mineral analysis performed by the lab. Over the last 15 years, PetAg® powdered milk replacers have tested lower in overall ash than Fox Valley Nutrition milk replacers, averaging 25% less in Calcium and 15% less in Phosphorus. This trend continues with the new GME® formulation, down 9% from the pre-2022 sample in overall ash level. Calcium tested at .82% (well below the generally accepted minimum concentration of 1% for milk) and 0.54% for Phosphorus. [This is another example where, in this case, the Ca:P ratio of 1.52 can be misleading. While a ratio of 1.52 is very acceptable in milk, in this case it is calculated from Calcium and Phosphorus concentrations that are remarkably low. It is always advisable to look at the individual mineral concentrations as well as the ratio.] As for the other minerals, most other macro mineral concentrations tested at 20-40% lower concentrations, while all micro mineral concentrations tested higher.

GME 2022 Minerals.jpg

Fatty acid profile

The fatty acid profile of the new formulation is shown in the following table. It shows an 8-percentage point drop in total saturated fat when compared to the pre-2022 formulation, with a corresponding 7 percentage point increase in polyunsaturated fats. This is likely a change in the mix of vegetable oils being used, with a 26% increase in linoleic fatty acid, which could suggest an increased mix of sunflower, safflower, soybean, corn, and/or canola oil - which are all primary sources of linoleic acid. [The 25% decrease in total saturated fats would be problematic for species that have dietary needs of a higher concentration of medium chain triglycerides (MCT C:8 - C:12) such as Eastern cottontails and may require very minute MCT supplementation to formula recipes.]

GME 2022 Fatty Acid Profile.jpg

Peroxide Value (PV) test results

The 2022 GME® samples were 7 - 18 months post manufacturing when tested for rancidity, with test results as high as 230. These test results are well above the maximum Peroxide Value(PV) of 10. Seven pre-2022 samples had been previously tested (2017-2019) with a mean test PV of 50 (ranging from 14 to 143). GME® has generally shown test results of far less robust shelf stability (lower PVs) than the other PetAg® products of Esbilac® and KMR®. Subsequent testing is needed to determine if the new formulation continues to demonstrate even further deterioration in shelf stability during the quoted 24-month product life span.  

GME 2022 PV history.jpg

Physical characteristics - artifacts [tests performed by WildAgain]

The process to determine the average weight of a tablespoon volume of the new GME® involved 45 individual scoops of powder that were weighed on a gram scale. During one of the scoops, a remarkably large artifact was observed as shown below. Upon examination, it was found to be hard in texture and weighed 0.08grams. After placing the artifact in warm water for an hour, it still remained hard and stiff and had only slightly begun to break into a few smaller pieces. Composition and origin of the item remains unclear.

Additionally, after preparing the powder for immediate use (no 8-hour rest), smaller semi-hard and non-reconstituted particles were captured by the largest opening sieve (500µm) as shown below. The composition of these particles is unknown, but suggests a lack of acceptable micronization of certain ingredients for a powdered milk replacer product.

GME 2022 Solid particle composite .jpg
Solid particle closeup IMG_7693 copy.jpg

Physical characteristics and measurement error [tests performed by WildAgain]

The new GME® formulation continues to have the characteristic very loose, fluffy and sticky consistency as in prior formulations, and similar to other PetAg® powdered milk replacers. This is likely a result of the spray-drying manufacturing process. This physical property continues to provide challenges when measuring a given amount of powder to include in a formula recipe. Mixing by parts using the provided scoop or some other volume measure results in measurement error ranging from +4.7% to -16.5. This is an almost 500% increase in the error range from a prior lot manufactured 2020. Weighing the powder eliminates this unnecessary user induced error, provides for a uniform formula at each mixing and preparation (Mixing Guide), and helps insure consistent nutrition in the formula.

Another benefit of weighing (versus volume scooping) is the notable trend of GME® 'gaining weight' over the past 15 years. Averaging 6.5 grams per tablespoon in 2008, the 2022 sample now averages a weight of 8.5 grams, a 30% gain in the weight of the powder over that time span. 

GME scooped weights new v old.jpg
GME weight history.jpg

Reconstitution tests - wetting and sinking [tests performed by WildAgain]

The 2022 GME® sample demonstrated very good wetting and sinking of the dry powder, being completely submerged in the warm water within 30 seconds (shown in the first image below that is a side by side of normal lighting (left) and a copy with enhanced contrast (right) to show the submerged but undispersed powder). However, even with the fast wetting and sinking performance, much of the wetted powder had not fully dispersed in the water after 5 minutes. This demonstrates that mechanical mixing would be required to achieve more complete reconstitution.

GME 2022 WetSink Compare .jpg

Reconstitution tests - dispersal [tests performed by WildAgain]

The formula was whisked by hand for 5 minutes (or longer) until all visible dry powder had been determined to be dispersed so no small clumps were visually present – and it appeared smooth, ‘milky’ – and presumed ‘ready to feed.’ The formula was then poured through the stack of sieves, with the largest mesh size on top (500µm). The image that follows shows the unwetted powder retained (trapped) by the 500µm sieve, even though visually it had appeared that the formula just prepared had been completely mixed and free of any dry powder clumps. The image on the left is the formula that was mixed and not allowed to rest, simulating an instant mix use/feed as directed on the product label instructions. The image on the right shows significant improvement (in terms of less unwanted, dry powder) after allowing the formula to simply rest a full 8 hours

GME 2022 Pour Comparison.jpg

The instant mix (no rest sample) showed a surprising and disturbing outcome in the smaller mesh sieve. After removing the 500µm and 250µm sieves from the stack, the 125µm sieve was found to have retained enough unwetted, dry powder to actually obstruct flow of liquid through the sieve (left image below). A plastic scraper was then used to see if some of the liquid and powder could be forced to pass through the smallest mesh sieve. The image on the right shows that almost all the liquid could be forced through, but the undispersed powder remained in the form a thick wet sludge. Most would agree that this level of sludge would be difficult if not impossible for young, developing GI tracts to digest, absorb and utilize, and likely result in severe intestinal distress in very small, young wild mammals. The sample allowed to rest for 8 hours (not shown below) showed very minimal liquid flow obstruction and no noticeable wet sludge – and could be generally expected to be easier for young wild mammals to digest.

GME 2022 125 Residual sludge .jpg

Reconstitution tests - Observed results

Instant mix - no resting time. When compared to the prior formulation, the new GME® shows a 90% reduction in the amount of dry, unreconstituted powder retained/trapped in the stack of sieves when prepared for use as an instant mix. This represents significantly more complete dispersal and dissolution (reconstitution) of the powder. The chart below shows the sieves retained (trapped) 1.5% of the dry powder after the sieves were drained and dried of all remaining moisture. Most of the dry powder material was retained in the 125µm sieve. (For reference, complete dissolution would achieve the normal range of milk particle size 10 to 100 times smaller and would easily pass through the last sieve.)


The image that follows shows what the amount of dry, unreconstituted powder looks like in the 125µm sieve after drying at 165 degrees F after 2.5 hours. The left image is the 'instant use' sample, amounting to only about 1% of retained dry powder. admittedly not a large amount, but clearly enough to coat the bottom of the sieve and obscure view when held up to the light. The image at right shows the '8-hour rest' sample, with virtually no dry powder retained. 

GME 2022 250 v 125 compare IMG_7698 copy.jpg

Reconstitution tests - Observed results

Resting time of 8 hours. When the prepared formula sample was allowed to rest for 8 hours, a >99% improvement in dissolution resulted, with virtually no dry material remaining. This is also a significant >99% improvement over the pre-2022 GME® 8-hour rest sample. 

This improvement in dispersal is encouraging, placing the dispersal efficiency of the new GME® in first place when compared to all other commonly used powdered milk replacers, given the time to rest for 8 hours. This is apparent in the second chart below. This suggests that the added resting time is a critical step to achieve a suitable liquid formula for feeding for GME®, and any powdered milk replacer – and the health of young wild mammals to which it is fed.

Following the immediate two charts below is a visual presentation of how the two formulations of GME® performed in the sieves. They are presented in order of the largest mesh sieve to the smallest.

GME 2022 dispersal efficiency.jpg
GME 2022 Dispersal summary all products.jpg
GME 2022 500 sieve final.jpg
GME 2020 500 sieve Final.jpg
GME 2022 250 sieve final.jpg
GME 2020 250 sieve Final.jpg
GME 2022 125 sieve final.jpg
GME 2020 125 sieve fianl.jpg

Click here for Part 2. which discusses what some of these changes may mean to wildlife rehabilitators who have previously used GME® or are considering as an ingredient in a wildlife formula recipe.




Esbilac® is manufactured and sold as a food supplement for dogs, and not intended to be a sole source food for developing puppies. Wildlife rehabilitation is considered an off-label use.

Product assays performed by the independent lab adhere to the Official Methods of Analysis of AOAC INTERNATIONAL (Association of Official Analytical Chemists) and the Official Methods and Recommended Practices of the AOCS (American Oil Chemists Society).

The authors have no conflicts of interest with the independent lab, or any of the products or manufacturers discussed in this article.

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