Hi Duncan!
I agree with you on everything you've said. Regarding labels not
showing DE levels, there is a general guideline that was given to me to
help roughly estimate a foodstuff energy content based on the feed
label. Just another handy bit of information to have around
cluttering up the desk. Here goes:
Crude Fiber % DE Mcal/lb
2.0 1.62
4.0 1.55
6.0 1.45
8.0 1.35
10.0 1.25
12.0 1.15
This was out of my syllabus from one of my nutrition classes, it's cited
as originally coming from the Stud Manager's Handbook by Meadows. It
looks like the correlation is fairly linear, so maybe somebody clever
with a calculator could extend the estimates further. I don't know if
this would still apply in manufactured feeds that had a high added fat
content. Since added fat adds additional energy but no fiber, it seems
to me that the numbers would be skewed. However, since fat content is
also listed on the feed label, it shouldn't be too hard to calculate the
energy provided by added fat.
See ya,
Susan