You can make an argument that FBS is not adding to the suffering of animals. At the moment it is just collected as a side product and most of it is thrown away.
There are always multiple products from raising an animal. Some of them, especially the filet pieces, drive the number of animals being raised and slaughtered. Others are sold at a discount, sometimes quite sharp, some edible products are actually thrown away. You don't drive animal cruelty with FBS, or even low-priced parts of the actual animal. Up to the point where demand is outstripping the "side chain supply".
Can't say all that for milk. Cows are raised for giving milk, and at the end of their lives slaughtered. They have to give birth to calves every year, half of which are male and slaughtered much earlier. That meat is actually cheaper than meat from cattle raised specifically for meat generation, because it's a side chain and the meat is of lesser quality but it is available. A similar dynamic applies to chicken.
There are always multiple products from raising an animal. Some of them, especially the filet pieces, drive the number of animals being raised and slaughtered. Others are sold at a discount, sometimes quite sharp, some edible products are actually thrown away. You don't drive animal cruelty with FBS, or even low-priced parts of the actual animal. Up to the point where demand is outstripping the "side chain supply".
Can't say all that for milk. Cows are raised for giving milk, and at the end of their lives slaughtered. They have to give birth to calves every year, half of which are male and slaughtered much earlier. That meat is actually cheaper than meat from cattle raised specifically for meat generation, because it's a side chain and the meat is of lesser quality but it is available. A similar dynamic applies to chicken.