Assuming the 'refining" doesn't have to do with refined petroleum oil
<g>, the high cost of cold-pressed oils aren't IMHO, justified. The
primary goodie horse owners are looking for is a concentrated source of
energy and that's the same in vegetable oils, regardless of whether the
oil was cold-pressed or not. Vegetable oils, both cold-pressed and
refined, do contain some of the fat-soluble vitamins, and probably
cold-pressed oils do contain a higher amount. However, if you're only
feeding a cup or two (which includes most people), the oil isn't a
significant source of those vitamins. Also, those fat-soluble vitamins
are easily and quickly oxidized (destroyed) when exposed to light and
oxygen, so the minimal benefits of cold-pressed oils vs. regular old
Wesson are negated by leaving the top off the bottle for awhile, or
allowing air head space to accumulate at the top of the bottle as the
level goes down.
Regardless of the source of the fat, you should always keep the
container tightly closed and in a cool, dark storage area.
Refrigeration is great, but not always feasible. If you buy your oil in
larger containers, you can minimize the oxidation by pouring off a
week's supply into a smaller bottle and keeping the main supply tightly
closed, so you're not opening it up everyday and introducing more
oxygen, which will hurry up rancidity.
A well-balanced ration is going to supply a more than sufficient supply
of all the vitamins which might be found in vegetable oils (cold-pressed
or refined), with the possible exception of Vitamin E. If your horse is
getting eight pounds or so of alfalfa a day, he's probably getting
plenty of Vitamin E. To supply an adequate amount through vegetable
oil, you'd have to feed close to 3 gallons a day. Not likely. Or you
could feed 1/4 ounce of a commercial Vitamin E supplement and not worry
about it. Much easier and alot cheaper. Vegetable oils definitely have
their benefits, but I wouldn't go spending alot of money on one oil over
another based on whether it was cold-pressed or not. If you really want
the most from your oil, save up the money you're not spending on
cold-pressed oils and buy a used refrigerator to keep the vegetable oil
in to minimize oxidation.
Susan Garlinghouse