Calorie content declarations on petfood labels: What’s the best method?
With new requirements for calorie content statements on the horizon, what’s the best method to determine ME?
As previously reported (see www.petfoodindustry.com/47831.html), recent amendments to the Association of American Feed Control Officials (AAFCO) Model Regulations for Pet Food and Specialty Pet Food will require calorie content statements on all dog and cat food labels within the next few years (the exact time frame for compliance is still to be determined).
There currently are two AAFCO-accepted methods upon which to determine and report metabolizable energy (ME). The first method is to conduct proximate analyses (crude protein, crude fat, crude fiber, moisture and ash) and insert the average results into the "modified Atwater" equation (the "calculation method"). The other method is to conduct a feeding trial to determine digestibility (with or without urine collection) and use the resulting values in a different equation to estimate ME (the "feeding trial method"). While the latter method is generally regarded to be more accurate, recent research has shown that the results derived from the former method may not be as aberrant as previously presumed.
Contrary to some speculation on the Internet, the modified Atwater equation was not developed by AAFCO as a means for the industry to purposefully underestimate calorie content and hence justify higher feeding amounts. Rather, it was proposed by a researcher in the 1980s as a better predictive…