Hi, Chidiock:
>Somewhere in this thread someone (Hal?) said something like  "grass does
>not want to be eaten".

Grass does want its leaves to be eaten in so far as that encourages the
eating of any broadleafs nearby.  Furthermore,  the leaves are succulent
and sweet.  Grass "gone to seed" is less palatable and nutritious -- the
seed head is the least palatable.  Observing the blue stem in my brothers
pastures,  cattle will eat the grasses gone to seed only as a last choice,
if even then.

>  Yet insofar as horse are concerned, this is an effective method of seed
> distribution. The principal food supply for 19th century urban
> populations of english sparrows , at least the the United States, was
> undigested hay seeds in horse manure.

Working horses were fed threshed grain.   Seed in the stabled horse's hay
would have been incidental, and certainly not on any choice of the
horse.  You harvest  green grass for fodder, and stubble for bedding.   My
present opinion would be that pastured and wild horses would not seek to
eat grass seed heads.  If the birds found grass seeds in urban manure,.
that's a  sign that there is no value to a horse of eating unmilled
grain.  The wild horses digestion would not likely have been part of the
wild grass's seed distribution.   (horses have been introduced into South
American rain forests to replace the fruit seed spreading function of
Pleistocene giant sloths).

>, at least the the United
>States, was undigested hay seeds in horse manure.  Is it perhaps possible
>that gluten evolved as an agent to speed transmission of proto-wheat seeds
>through the consumer's gut,

No, because if the gluten was exposed to the gut, the seed would not be
viable.  Gluten is not water soluble unless less milled and would not much
contact the gut unless milled and would not germinate if
milled.  Proto-wheat seeds would be even less accessible than wheat, that's
why we created wheat.

There is a reason for the primate to eat an apple or a bison, but none at
all to eat a grass seed head.  OK, for about a week, wheat berries are
sweet and palatable and maybe even safe, but it is a meticulous Russian
doll act to get out each berry.  But that doesn't benefit the grass because
no viable seed could be passed, the grass's defence at that point before
ripening is the irritating seed head.

Improperly introducing a cow to grain feed can kill it.  "Walking off" a
lodged cow is a bit more *substantial* than that bud light fart commercial.

You only feed a *lot* of milled grain to an animal you are going to butcher
or work to death and then butcher.

>there by increasing the number of undigested
>seeds and providing an reproductive edge over non-gluten bearing grains?

My theory on gluten is it simply evolved as an inherent nutrient storage
for use by the sprout.  Certain lectins may have been integrated into the
glutens to injure those animals that might develop capabilities of eating
and milling the seeds with their teeth or beaks.

>Wheat, however, has its origins in the Middle East, and the primary grass
>eaters in that region would be not horses but ruminants such as sheep,
>goats and the like.  As I am unfamiliar with the output of such critters,
>here is my question--Is their digestive process so efficient as to preclude
>the passing of undigested seeds?

Since there is no nutrition in the ripe seed head except for the
seeds,  animals would eat the seed head only if they can digest the
seeds.  Plants that want animals to spread their seeds invest energy in
producing fruit flesh to keep the animal alive as it passes on the
undigestible seeds,.

Hal