> from a pregnant mare

I’m quite skeptical about this. How do they obtain and culture chicken cells from a horse?

Not the cells, but the growth medium. You need a growth medium to grow cells in a culture, because there's no support from the rest of the animal for growth. Normally the animal would provide blood, etc. to the tissue, but there is no animal in this case.

It's the medium, not the genes. Like someone else mentioned, it's called fetal bovine serum (presuming GP meant "cow" and not "mare") and it's used in large quantities.

Ah, that makes sense! Thank you!

I’m much less skeptical now

> technique called bloodletting

The technique is called a "biopsy" and while it does hurt, the animals recover pretty quickly from it. Branding is far more painful.

In a world where the animal’s well being is valued more then the economic output of the producer this might be true. However in our current economic system the economic incentive favors taking as much blood as possible without killing the animal while providing minimal relieve.

I have no faith in a regulatory framework being enacted and enforce which will minimize this suffering while keeping businesses profitable.

Given the topic of animal suffering here, what does the full picture of an animal used for this purpose look like? Are they treated any different to animals intended for direct consumption?

My assumption is that the animals will lead the same life. While this is something that'd cut down direct consumption I doubt that's ever eliminated.

So it becomes a math game. Either this cow produces the 700lbs of meat in a normal lifetime or with lab meat it produces n tons of meat (depending on how much meat can be produced per sample).

Who knows, maybe this ends up with a few cows living long lives since it's not their meat that matters but rather the quality of the stem cells they produce. But I'm guessing it's more likely these stem cells first get extracted from animals either already butchered or destine for the butcher.

> it's not their meat that matters but rather the quality of the stem cells they produce.

Note that we are talking about the growth medium here, which is used to grow the stem cells into the final product. So it should be the quality—or much rather the quantity—of the extracted serum from the animal (specifically the animal’s fetus or womb).

It’s call FBS, and it can be grown in a lab, too (if it’s even required…). See companies like Future Fields.

In practice, artificial FBS or FBS-free medium can be very tricky to use successfully. It's definitely not a solved problem yet.

It is a solved problem, UPSIDE (and I believe one other company) now have animal-component-free medium.

These products have existed for decades (I know because I’ve used some of them), but it is not a solved problem. For all but the easiest cell cultures, growing cells without FBS is extremely tricky. I know that marketing materials (and some publications almost certainly by the manufacturer) say otherwise, but that’s marketing for you.

Not every type of cell or tissue has the same requirements, and things get difficult very quickly as soon as you deviate from the most common cultures. Tissues and non-cancerous (or in technical jargon: non-immortalized) cell lines are usually much, much, much more difficult.

And even if you manage to grow your cells, “serum-starving” will likely happen due to some unknown missing nutrient / factor, which will stress your cells and alter their phenotype. Even if they don’t lose their adherence, undergo apoptosis, or some pathologic autophagy, they may produce all sorts of extracellular vesicles.

FBS is really expensive, and quite mysterious. Nobody really knows what’s in there exactly. [1] Researchers would love to be able to stop using it, because it could mean more reproducible results, and at scale, fewer expenses. Unfortunately, FBS is also unreasonably effective, so we continue to use it still.

[1] This is only a slight exaggeration, but it’s approximately true. Trust me, I know this sounds like a preposterous claim. But this is an absolutely-insane rabbit hole where a lot more research is very-needed. A full characterization of FBS and its effects on cells does not exist, and is much more complex than it probably sounds.

This is wrong. UPSIDE’s meat is grown in animal component free medium. That’s one of their key innovations.