Ensiling and its fermentation is akin to cooking in that it changes the molecular form of some of the silage and so makes it better for some animals’ nutrition; it’s a kind of pre-digestion (same w/beer and cheese).
In longer form: silage has less available caloric energy overall since some is converted to waste heat by the bacteria. However, more of that initial energy is available to the consuming animal because it’s more palatable (it will confer no energy if uneaten) and more readily digested (both physically, because it’s softened, and chemically, because the bacteria have essentially jumpstarted catabolism).
rambly stuff:
I return to these four words whenever discussing the sad state of most contemporary dietary thought:
guts are not calorimeters
That is to say, calories aren’t the whole story but at best a small chapter. Different foods (and different states of foods) are digested and then used in the body differently. Also, genes, age, fat stores & hormonal milieu, mood, illness, activity levels & routine, etc all affect digestion and subsequent metabolism.
In so many words: the bulk caloric content of a given food isn’t especially revelatory of its nutritional suitability, and this is true for all animals and foods. It’s more useful to determine, for example:
- how much of a food does an animal digest (in vertebrates, how much gets into the blood plasma)
- what is the molecular form(s) of the food thus digested, and
- what does the body do with those molecules
/yeesh, I write terribly, re-wrote most of that
