New KMR® (2022) - Part 1. How has it changed?
Long term users of PetAg®'s KMR® have seen labels come and go. PetAg®'s KMR® has a new label featuring a Black and Tan kitten 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 test results. Part 2 discusses and offers suggestions on what these changes mean (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.). Wildlife rehabilitators purchasing a new KMR® (2022) may be hesitant and wary after issues from previous PetAg® changes.
Part 1. This analysis provides the chemical analysis of the new 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 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 powdered cellulose and oat fiber.
√ Proximate analysis. Protein has decreased 5% (still within tolerance of Guaranteed Analysis-GA); Moisture has decreased but remains above the GA maximum of 5%; Fat remains unchanged, Crude fiber is notably absent. These changes result in a 44% increase in calculated carbohydrates (NFE).
√ Ash. As for dietary minerals, the new formulation shows a 12% decrease overall, as well as individual decreases in all mineral concentrations except for sulfur and magnesium. Calcium, phosphorus and potassium are all lower ranging from 13 - 20% decreases.
√ Fatty Acids. The profile shows a 24% increase in polyunsaturated fats (a 60% increase in Oleic and Linoleic acids combined), and a 37% decrease in overall saturated fats.
√ Rancidity. KMR® continues to demonstrate concerning shelf-stability issues with two 2022 samples testing at PV's from 55-64 at only 10-11 months since manufacture, well above established guidelines for edible oils. This continues the trend of elevated PV levels in three 2021 samples tested at less than 18 months old. Proper storage is still critical.
√ Physical characteristics. Powder is still loose, fluffy and sticky. Measuring powder by volume or parts rather than weighing continues to cause error rates of + / - 11 to 13% from the calculated average weight. The average weight of the powder is now 40+% heavier by volume over the last five years.
√ Reconstitution (dispersal and dissolution). An 8-hour resting period from preparation (mixing) to final use (feeding) improves final reconstitution by 66%. Without the rest period and quickly prepared for an instant use/feeding, over 18% 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 and a higher concentration of maltodextrin. 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 have changed in their presence/absence and likely concentrations. Oat fiber and powdered cellulose are new ingredients presumably intended for prebiotic benefits that are essential for digestion, development, and the immune system.
The fermentation products presumably intended for probiotic benefits have not changed. They are listed in the same order of prominence, though again, actual concentrations may have changed in the new formulation.
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.
Moisture still exceeds the maximum guarantee of 5%, though has improved, down 17% overall from the pre-2022 sample. This results in a higher percent of overall total solids in the new formulation. Also notable is the 5 % drop in protein concentration. Fat remains unchanged, Crude fiber is notably absent. These changes result in a 44% increase in calculated carbohydrates (NFE). Due to the higher carb content of the new formulation, the metabolizable energy content (ME Kcals) equals 4.91 per gram of dry powder. That is a slight 3% increase over the 2021 sample of 4.76 Kcals/gr. These changes in the proximate values may require adjustments to previously used formula recipes, which 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. 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 KMR® formulation, down 12% from the pre-2022 sample in overall ash level.
Calcium tested at 1.28% and 0.86% for Phosphorus, both lower the the prior formulation. [This is another example where, in this case, an increase in the Ca:P ratio of 1.49 can be misleading. While a ratio of 1.49 is very acceptable in milk, in this case it is calculated from Calcium and Phosphorus concentrations that have decreased from prior years. It is always advisable to look at the individual mineral concentrations as well as the ratio.] As for the other minerals, most other concentrations tested at lower concentrations.
Fatty acid profile
The fatty acid profile of the new formulation is shown in the following table. The profile shows a 24% increase in polyunsaturated fats (a 60% increase in Oleic and Linoleic acids combined), and a 37% decrease in overall saturated fats. This is likely a change in the mix of vegetable oils being used, with a 60% increase in linoleic fatty acid, which could suggest an increased mix of vegetable oils with higher saturated fatty acid content. [The 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.]
Peroxide Value (PV) test results
The 2022 KMR® samples were only 10 - 11 months post manufacturing when tested for rancidity, with unexpected and surprisingly high test results of 54.6 and 64.0. These results are significantly above the max Peroxide Value (PV) of <10. 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 needed to determine if the new formulation continues to demonstrate unacceptable shelf stability during the quoted 24-month product life span, especially so early after manufacture.
Physical characteristics and measurement error [tests performed by WildAgain]
The new KMR® 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 +11.0% to -13.4%. This is an approximately 9% increase in the error range from a 2021 lot manufactured just 8 months prior. 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 KMR® 'gaining weight' over the past several years. The 2022 sample now averages a weight of 8.2 grams, a 40+% gain in the weight of the powder over the last 5 years.
Reconstitution tests - wetting and sinking [tests performed by WildAgain]
The 2022 KMR® sample demonstrated reasonable wetting and sinking of the dry powder, being about 95% submerged in the warm water within 5 minutes (shown at left looking down into the beaker filled with formula). The image at right (with enhanced contrast) shows the sunk/submerged tbut 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 4.5 minutes until all visible dry clumps were not present.
Reconstitution tests - dispersal [tests performed by WildAgain]
The formula was whisked by hand for 4.5 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 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.
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
Instant mix - no resting time. When compared to the prior formulation, the new KMR® shows a 74% increase 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 less complete dispersal and dissolution (reconstitution) of the powder. The chart below shows the sieves retained (trapped) 18.3% 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 right 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 left shows the '8-hour rest' sample, with virtually no dry powder retained.
Reconstitution tests - Observed results
Resting time of 8 hours. When the prepared formula sample was allowed to rest for 8 hours, a 66% improvement in dissolution resulted, with less dry material remaining. While this shows the benefit of the 8-hour rest period, it is unfortunately 5 times the amount of dry powder retained by the sieves versus the pre-2022 KMR® 8-hour rest sample.
This result in dispersal is not encouraging, placing the dispersal efficiency of the new KMR® in last 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.
Following the immediate two charts 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?"
KMR® 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.