Unfortunately, there is scant documentation available to compare the fats of grass-fed beef and pastured pork, so much of this post compares ordinary beef and pork fats.
Tallow is the fat from the the loin and around the kidneys of beef cattle, and is usually called suet before it is rendered. It has a waxy feel, rather than greasy, even before rendering. It is different than the fat in other parts of the beef, and as such has some specific properties.(Tallow can also be rendered from sheep and bison, but I have zero experience.)
Lard is rendered from the fat of hogs. The fat closest to the skin is a harder fat, better used for making sausage than rendering, although it does render. The layer of fat closest to the meat is ideal for rendering, as is the leaf fat around the kidneys.
From Nutrition Data, here are some stats on tallow vs lard (I assume both to be what is found in grocery stores, and not grass-fed), 100 grams of each:
Essential Fatty Acids:
Tallow contains 3100mg of Omega-6 and 600mg of Omega-3, for a ratio of 5:1. (The lower the ratio, the better for our bodies, and ideally 1:1 is best, although all researchers do not all agree.)
Lard (from hogs) contains 10,199mg Omega-6 and 1000mg Omega-3, for a ratio of 10:1.
(Click here for more on Omega-6 - Omega-3 and health)
Vitamin E per 100g:
Tallow = 2.7mg (14% DV)
Lard = 0.6mg (3% DV)
PUFAs per 100g (PUFAs oxidize and form unhealthy free radicals)
Tallow, 4g
Lard, 11.2g
EatWild, on their Health Benefits page, says grass-fed meats contain 2-4 times the Omega-3 of grain-fed meats. Omega-3 is formed in the chloroplasts of green leaves and algae, so it understandable that Omega-3 would be high in grass-fed meats. Since humans generally don't eat grass, we get our Omega-3 from grass-fed meats, seafoods, and a few seeds and nuts like flaxseed and walnuts. It is estimated that only 40% of Americans eat an adequate amount of Omega-3 essential fatty acids. (Essential because the body needs them and cannot make them from something else.)
“Omega-6 is like a fat producing bomb...” ~ French researcher Gerard Ailhaud
Omega-6 fatty acids are essential for health, but the amount consumed by most Americans increases the risk of obesity, diabetes, inflammatory diseases, and cancer. Omega-6s are most abundant in liquid vegetable oils such as canola, corn, safflower, and cottonseed oils. (However, olive oil is low in omega- 6 fatty acids.)
CLA (Conjugated Linoleic Acid), another fatty acid, is an antioxidant with anti-cancer properties. The richest source known for CLA is grass-fed beef. The tallow from their suet is high also because CLA is stored in fatty cells. In fact, meat and dairy products from grass-fed animals can produce 300-500% more CLA than those of cattle fed grains. (36)
Vitamin K2
"Vitamin K2 has a very interesting role: it puts calcium where it belongs (in the bones and teeth) and keeps it away from the places it doesn’t belong, such as the arteries, where plaques calcify. Vitamin K2 is essential for healthy development and growth. Its effects are subtle: though K2 is necessary for bone density, it also prevents premature calcification of the cartilaginous parts of bones.
Vitamin K2 can be made in the body from vitamin K1, which is found in green vegetables, but ideally your diet will contain ample sources of K2 itself. Get your K2 from the butter, organ meats, and fat of animals raised on grass. A reliable sign of K2 is the rich yellow color of butter from cows on grass; K2’s precursor is related to beta carotene." (1)
From that quote, I assume tallow made from grass-eating beef is higher in K2 than lard from pastured hogs who do forage but do not eat just grass. Most pasture-raised hogs are given supplemental feed which often includes whey.
Vitamin K2
"Vitamin K2 has a very interesting role: it puts calcium where it belongs (in the bones and teeth) and keeps it away from the places it doesn’t belong, such as the arteries, where plaques calcify. Vitamin K2 is essential for healthy development and growth. Its effects are subtle: though K2 is necessary for bone density, it also prevents premature calcification of the cartilaginous parts of bones.
Vitamin K2 can be made in the body from vitamin K1, which is found in green vegetables, but ideally your diet will contain ample sources of K2 itself. Get your K2 from the butter, organ meats, and fat of animals raised on grass. A reliable sign of K2 is the rich yellow color of butter from cows on grass; K2’s precursor is related to beta carotene." (1)
From that quote, I assume tallow made from grass-eating beef is higher in K2 than lard from pastured hogs who do forage but do not eat just grass. Most pasture-raised hogs are given supplemental feed which often includes whey.
Smoke-points
Why is the smoke-point important? Certainly the harsh smell of smoking fats in our kitchens is not pleasant! The more important thing, though, is that when a fat begins to smoke, it is chemically breaking down. It is believed that when a fat breaks down (goes past the smoke-point), a large number of free radicals (which are damaging to the human body) are formed.
Lard 370ºF
Tallow 420ºF
Just FYI (and because the information was handy), a few other smoke points:
Butter 300ºF
Extra-Virgin olive oil 320ºF
Coconut Oil 350ºF
Ghee 375ºF
Chicken, Duck or Goose fat 375ºF
Lard and tallow for deep-frying can be re-used. If you cook something in tallow and want to be sure it keeps no tastes or odors before re-using, you can simply drop some potato slices in the hot fat for several minutes and the potato will absorb any residuals. I use a fine-mesh strainer to strain tallow, and store it separately from 'new' tallow for re-use. Home-rendered lard and tallow are both stable when stored at cool temperatures, although my tallow seems to keeps longer than the lard.
Having said all that, nothing beats lard (which is softer) for a good pie crust... and nothing beats tallow for french fries!