New Goat's Milk KMR® (2022) - Part 1. New product (and comparison to regular KMR®)
As of mid-2022, PetAg®'s KMR® is now available in a goat's milk formulation, just as Esbilac® has been available in a goat's milk formulation (GME®) for years. This provides KMR® users with an alternative that is based on goat's milk/goat's milk components that are widely known to be more easily digestible and contain higher levels of certain key nutrients such as oligosaccharides. In order to assist users in deciding if and which KMR® might be best for their situation, WildAgain had various lab tests conducted on the new Goat's Milk KMR®, as well as performed WildAgain's standard reconstitution tests. This article (Part 1) discusses those test results and provides a side-by-side comparison between this new product and the regular KMR® (also newly reformulated in early 2022). Part 2 discusses and offers suggestions on the new product and how it differs from the regular KMR® (PDF).
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.). This also holds true with the introduction of variations or reformulations of existing products, such with this new KMR® using goat's milk as the predominant base of ingredients. Wildlife rehabilitators considering the use of this new Goat's Milk KMR® (2022) may be hesitant as there is little reported experience with its use in substitute milk formulas for wildlife.
Part 1. This analysis provides the chemical analysis of the new goat milk formulation of KMR® 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. As a reference point, many of the chemical and physical characteristics are compared to the regular KMR® formulation (also reformulated in early 2022 and currently available for purchase).
Part 2. An accompanying article discusses some of these test results and offers some suggestions that wildlife rehabilitators may consider when understanding the key differences between the two KMR® products (cow milk based versus goat milk based).
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 between the two KMR®'s, though likely in different concentrations or amounts. The primary difference is the predominate use of dried goat milk powder in the goat's milk product, and the exclusion of dried skimmed milk and cream (both cow sourced). Dried corn syrup is omitted from the goat's milk formulation, now contains pribiotics: powdered cellulose, fructooligosaccharide and oat fiber.
√ Proximate analysis. Both products share the exact same Guaranteed Analysis, but recently changed to 40% protein and 28% fat beginning in 2022. All components adhere to the guaranteed min/max amounts except for moisture, which exceeds the 5% maximum.
√ Ash. As for dietary minerals, it is not surprising that the goat milk formulation is 22% lower in total ash. A relatively lower total ash content is not uncommon among other goat milk based powdered milk replacer products. Calcium and phosphorus are both lower 24-25%.
√ Fatty Acids. The profile shows the goat milk KMR® with a higher concentration of saturated fats and a corresponding lower amount of monounsaturated fats. Polyunsaturated fats are about the same.
√ Rancidity. The Goat's Milk KMR® tested free of rancidity at 2.5 months into its 24 month shelf life. This contrasts with two samples of the regular KMR® that continue to demonstrate concerning shelf-stability issues testing at a PV's of 55 and 64 at only 10 - 11 months since manufacture, well above established guidelines for edible oils.
√ Physical characteristics. Powder for both products is loose, fluffy and sticky, and they share roughly the same average weight per tablespoon of volume. Measuring powder by volume or parts rather than weighing continues to cause error rates of + / - 9 to 14% from the calculated average weights of the two products. Percent error with each scoop is the same for both products at + /- 4%.
√ Reconstitution (wetting and sinking). Very good performance when correctly adding powder to warm water, with test samples 85% submerged in <2 minutes.
√ Reconstitution (dispersal and dissolution). An 8-hour resting period from preparation (mixing) to final use (feeding) improves final reconstitution by 79% for the goats milk KMR®. Without the rest period and quickly prepared for an instant use/feeding, about 4% of powder remains dry and not fully reconstituted. This is 5-6 times better reconstitution performance than seen with the regular KMR®
Ingredients (as listed on the package label)
The following table lists a side-by-side comparison of the ingredients of the two KMR® formulations - one goat milk based and the other cow milk based. The notable and most obvious difference is the use of dried whole goat milk powder in the Goat's Milk KMR® and absence of dried skimmed milk and cream (both cow milk sourced). Another difference in the Primary Ingredients listed is the absence of dried corn syrup from the regular KMR®. All other ingredients are the same, but their respective order of prominence has changed indicating that concentrations or amounts have likely changed.
The list of Secondary Ingredients shows many small-quantity additives and supplements differ in their presence/absence and likely concentrations. Powdered cellulose, fructooligosaccharide and oat fiber are included in both products presumably intended for prebiotic benefits that are essential for digestion, development, and the immune system.
The included fermentation products presumably intended for probiotic benefits are the same in both products. They are listed in differing orders of prominence, suggesting actual concentrations are different.
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.
Both products are now based on the new overall KMR® 2022 formulation of 40% protein and 28% fat, which is a change from prior years when it was 42% protein and 25% fat. While PetAg® provides no explanation for this change in protein and fat, it could be to more closely align a prepared formula [1 part powder with 2 parts water] with the protein/fat concentrations found in cat milk. Moisture exceeds the maximum guarantee of 5% in both KMR® 2022 and Goat's Milk KMR®. The fat content in the Goat's Milk KMR® exceeds the Guarantee by over 12%, which would need to be taken into account when constructing a formula recipe. Due to the higher fat content, the metabolizable energy content (ME Kcals) of the Goat's Milk KMR® equals 5.17 per gram of dry powder. That is about 5% higher than the regular KMR® at 4.91 Kcals/gr. Formula recipes using either product can be easily calculated with the Wildlife Formula Calculator.
Ash - dietary minerals
The following table shows the results of the dietary mineral analysis performed by the lab. The Goat's Milk KMR® tested 23% lower in overall ash than the regular KMR®, averaging 25% less in Calcium and 24% less in Phosphorus. All other dietary minerals showed slight differences between the two products as shown in the table below.
As just mentioned, both Calcium and Phosphorus are lower in the Goat's Milk KMR®, yet the Ca:P ratio is virtually the same. This is another example where, in this case, the Ca:P ratio of 1.49 can be misleading if viewed as single measure of Calcium and Phosphorus in a product. While a ratio of 1.48 or 1.49 is very acceptable in milk, in Goat's Milk KMR®, it is calculated from Calcium and Phosphorus concentrations that are 25% lower than in KMR®. It is always advisable to look at the individual mineral concentrations as well as the ratio - both are important.
Fatty acid profile
The fatty acid profile of the two products is shown in the following table. It is notable that the Goat's Milk KMR® has a more even balance between the saturated, polyunsaturated and monounsaturated fatty acids. By comparison, the Goat's Milk KMR® has a higher concentration of the saturated fats especially in the medium-chain triglycerides of caprylic and capris acids. This would be of significant benefit to a species such as the Eastern cottontail that has a dietary need of a higher concentration of medium chain triglycerides (MCT C:8 - C:12).
Peroxide Value (PV) test results
Two Goat's Milk KMR® samples were tested for rancidity, with findings reported as 'not detected,' meaning the results did not exceed the minimum reporting threshold of a value of 2. The two samples were relatively fresh at only 60-75 days post manufacturing so a 'not detected' or very low PV would not be unexpected. Subsequent testing is needed to determine if the new goat's milk formulation continues to demonstrate acceptable shelf stability during the quoted 24-month product life span.
Conversely, two samples of regular KMR® at only 10 - 11 months post manufacturing when tested for rancidity returned unexpected and surprisingly high test results of 55 to 64. This indicates rancidity is present and increasing as time passes. These results are significantly above the max Peroxide Value (PV) of <10 for edible oils. Three 2021 samples had been previously tested with a mean test PV of 28 showing a trend of increasing PV results in less than 18 months of shelf life. Subsequent testing is also needed to determine if the regular 2022 KMR® formulation continues to demonstrate unacceptable shelf stability during the quoted 24-month product life span, especially so relatively early after manufacture.
Physical characteristics and measurement error [tests performed by WildAgain]
Both KMR® formulations demonstrate the characteristic very loose, fluffy and sticky consistency 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 +9% to -14% in the Goat's Milk KMR® and from +11% to -13% in KMR®. The expected error rate for both products is about 4%, either heavier or lighter in weight for a given scoop. 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.
Reconstitution tests - wetting and sinking [tests performed by WildAgain]
The Goat's Milk KMR® sample demonstrated very good wetting and sinking of the dry powder, being about 85% submerged in the warm water within 1.5 minutes (shown in the image at left below). The image at right shows the sunk/submerged but yet undispersed powder. This demonstrates that mechanical mixing would be required to achieve more complete reconstitution. The sample was then stirred with a small whisk for 4 minutes until all visible dry clumps were not present.
Reconstitution tests - dispersal [tests performed by WildAgain]
The formula was whisked by hand for 4 minutes 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 first image below shows the unwetted powder retained (trapped) by the 500µm sieve when poured immediately after mixing. Initially looking very smooth and silky, once sprayed with water, clumps of unwetted powder became obvious, even though visually it had appeared that the formula just prepared had been completely mixed and free of any dry powder clumps. The next image image a direct pour of the formula that was mixed, allowed to rest 8 hours, and then reheated to 110 degrees F. Compared to the instant mix images, this shows significant improvement (in terms of less unwanted, dry powder) after allowing the formula to simply rest a full 8 hours.
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.
Reconstitution tests - Observed results
When the prepared formula sample of Goat's Milk KMR® was allowed to rest for 8 hours, a 79% improvement in dissolution resulted, with less dry material remaining amounting to less than 1%. The following chart clearly shows the benefit of the 8-hour rest period. While the regular KMR® also benefitted from an 8 hour rest period, its reconstitution properties were much inferior as shown in the chart. The Goat's Milk KMR® has significantly superior reconstitution efficiency than the regular KMR®.
Following the chart below is a visual presentation of how the two formulations of KMR® performed in the sieves. They are presented in order of the largest mesh sieve to the smallest.
"What's it all mean?"
See Part 2 for analysis, discussion and impressions of this new Goat's Milk KMR® and how it compares to the regular KMR®.
Goat's Milk KMR® and KMR® are manufactured and sold as a food supplement for cats, and not intended to be a sole source food for developing kittens. 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.