Different species (and specific breeds) of animals have different fatty acid
ratios.  Diet has some effect but as Jens so ably points out......because of
their digestive tract, it is very difficult to change the ratios by feeding
different feeds.....although, there does seem to be a fairly substantial
difference in specific fatty acids when you compare grain fed to grass fed.

Remember that not only are the ratios important......the absolute amounts
are too.  For example the Japanese Wagyu breed of cattle produces beef that
has a higher ratio of unsaturated fats to saturated than most other beef
breeds BUT the beef is so fatty that you are still ingesting much more
saturated fat than if you consumed regular beef, not to mention the large
amount of unsaturated fat.

> I'm not sure if this is really a good answer to the
> question, but I suspect that it's more complex than
> simply what they are fed. Cows have a completely
> different type of digestive tract, i.e. four stomachs,
> than do pigs, who like humans only have one. For cows
> a lot of the digestive process is dependent on
> bacteria in the gut, but not so much for pigs or
> humans. So I think that even given the same diet, pigs
> would end up with different nutrients than would cows.
>
>
> --- Adrienne Smith <[log in to unmask]> wrote:
>> If animals make saturated fat from the carbs they
>> eat (ie grain fattened
>> cattle, etc), how is it that pork in this country
>> contains more polyunsatured fats
>> than say corn-fattened beef?