What parts of the cow can't be used?

You can’t get gelatin from hoof or horn (which are keratin), gelatin comes from processing collagen, mostly hides and bones.

Keratin can be processed into glue (hoof glue), but it’s not the same as hide glue.

Cattle shinbones and feet (but not the hoof) are processed into neatsfoot oil, a leather dressing.

Well, for breeds that need the horns removed before they go to the feedlot (and later the slaughterhouse), what do the people that remove the horns do with them?

Where I live, the Turkish supermarkets and butcher shops are full of cattle feet (whole, including the hoof), so I assume that Turkish people eat them somehow.

Offal and organ meats are also not uncommon here, though it seems different ethnic supermarkets stock different ones. I’ve seen (and occasionally bought and cooked) tails, tripe, hearts, lungs, kidneys, spleens, liver, whole heads, ears, snouts, brains, testicles, and tongues. And of course intestines, stomachs, and bladders are used for sausage casings.

One thing I never recall having seen is udder. I wonder if I could special-order it. Does anyone know a good udder recipe?

If someone is paying to receive the stuff from the meat processor, then yes, it’s being used. If the meat processor is paying to get rid of it, then no.

That’s the paunch I mentioned above. It can be composted and the compost spread on farmland. The question is the economics of doing this from the processing plant’s point of view. If you have a lot of material being produced in one area there might not be enough farmers nearby willing to pay for the material. The economics might reverse. Farmers will take the compost from the supplier that’s willing to pay them the most.

Horns can be ground up and used as slow-release plant fertiliser - typically sold as ‘hoof and horn’ - a coarse granular preparation that breaks down quite slowly and releases phosphorous and other nutrients - it’s often recommended to throw a handful in the bottom of a planting hole for fruit trees and shrubs.

Whilst that seems like a clear place to draw the line, I’m not sure it’s right.

I pay people to dispose of my old computer equipment, but the person taking it away is making a profit not only from me, but from reselling it as parts or scrap.
The cost of disposal is undoubtedly part of the recycler’s cost model, but it does not directly dictate whether or not the waste is really being ‘used’.

I see! What about horn-rimmed glasses? Do any manufacturers still use real horn rather than plastic?

Ah, I missed that entirely somehow.

I suppose the paunch includes feces. Speaking of infectious matter, is visibly diseased or parasitized meat used by anyone, or is that simply burned?

I see what you did there.

Sensible. As you’ve pointed out, a person may give something away or even pay to have it taken away, and that thing may still provide a benefit to the receiver (e.g. scrap metal, scrap electronics, or excessive amounts of organic material from a meat processor). I suppose for something to be truly useless, it has to end up in a landfill, which would only happen if it really did have no value to anyone.

It was stamped “condemned”. Which meant not for human consumption.

Not burned, but cooked and ended up on the table of animals further down the food chain.

I have dehorned a lot of cattle in my days ( even did it for a fee for others) and the horns were just tossed in the manure pile

Apparently nowadays most of the sheep grown in the US are grown for the meat. The demand for wool has collapsed so much that much of the wool that’s sheared off for the animals’ well-being is simply composted. Ditto the wool left on the animal at slaughter.

There certainly are some sheep breeds and sheep operations that specialize in wool, not meat. But they’re far in the minority.

The meat breeds tend to have course wool that was fine for carpets, seat cushion fill, and GI blankets. None of which use wool any more. The wool breeds have finer, more knitter-friendly wool.

Agreed.

…With the really nitpicky caveat (not relevant to the topic of slaughter waste) that the landfill operation isn’t actually procuring or sourcing it as a desired material.
(For example clay or other soil materials added to cap or layer landfills are being ‘used’, not ‘disposed of’)

I used to purchase ingredients for the animal feed plant where I worked. Among the ingredients I bought by the semi-truckload quantities were, slpeens, livers, tallow, kidneys, gelatin, feather meal. Feather meal and blood meal are very popular ingredients as they are in the upper 80’s% protein.

Spray dried blood was a popular protein source, truckloads a week were used. Every thing else is covered under the umbrella of meat and bone meal. It is all publicly traded on the commodities market.

Part of the plant was also a rendering plant processing seafood waste into fishmeal, oils and bone meals.

Sending waste products to a landfill costs money, selling it for processing earns money. Which do you think is preferred?

The amount of these waste products produced every day is hard for the average person to imagine, millions of pounds, and would quickly overwhelm any landfill. It all goes around and around until it comes out as an ingredient fed to some other animal. Then their scraps go around again.

Hood ornaments? I sure see a lot of decorative cattle horns around, especially in Texas. Sometimes they’re just polished and mounted on a wall. On the other hand, they can’t all be used for decoration I suppose, only the biggest and most impressive.

What about tail hair ?

Surprised you used “livers” in animal feed as when I worked in the packing plant, all livers were wrapped ,boxed, went in the freezer and shipped out when a semi trailer load was accumulated. Certainly …NOT… for animal feed.

By the way the gall itself can be used in painting. I remember using it as a kid to paint on some sorts of papers.