As opposed to common assumption, leather is not a by-product of the meat industry.
Leather is primarily produced from cows, raised for both flesh and Milk, and from other exploited "farm animals" such as Pigs, Sheep, Horses, Lambs and Goats. Their skin represents around 50% of the animal's total value for humans, which makes it the most valuable part of the exploited animal. Leather is not the by product, it is the prime product. Buying leather is supporting the meat industry and vice versa. The profits made from leather selling, reduce the meat prices and as a consequence enable more people to buy more meat. The meat industry can’t be separated from the leather industry. There are no two industries, they are both products of the same one, only different body parts.

Skinning

Slaughterhouses are intensive industrial plants for meat and leather production. There is no time to wait for the sentient and totally conscious animals to die before they are being skinned.
Due to the combination of working at full speed in a moving belt conveyor system and the general concept of animals as no more than meat and leather units, many of them are skinned while they are still conscious. They remain conscious and feel as their feet are being clipped off and their whole skin being torn out of their body.

An eyewitness tells: "Sometimes they have all the skin out and they're all peeled. Sometimes you can tell they're alive because when you look at their eyes, you can see the tears of a cow. And their eyes are moving and everything. But mainly they just make a lot of noise and are trying to kick."

Snakes and lizards are not slaughtered but are skinned alive while nailed, fully conscious, to a tree. They suffer for hours and even days before they die. That’s because the skin of snakes that is stripped off after they are dead, is considered not 'pliable enough for fashion' use.

Some goats are not slaughtered either, they are boiled alive to make soft leather gloves.

The March of Suffering

Many international retailers routinely use skins from cows slaughtered in India.
The slaughter of cows is legal only in a few Indian states, which means that cows are forced to travel for hundreds of miles to the few states where slaughter is legal.
Since the exploiters want to avoid paying the required taxes for commercial vehicles that cross Indian states, parts of the journey is done by foot, in a death march.
Since it is illegal to kill healthy, young cattle, they are often deliberately maimed. Their legs are being broken or they may be poisoned so that they would be declared fit for slaughter, not that many slaughterhouse workers care.

In these death marches, cows and buffaloes trudge hundreds of miles without food or water and with little rest. They are beaten mercilessly to be driven forward in the searing Indian heat. Their tails are being broken and tobacco and chili peppers are rubbed into their eyes in order to drive them on or force them to stand up when they collapse. Their hooves are often bleeding and worn down to the stumps.

The motored parts of this intolerable journey don’t fare much better. Crammed in the trucks, the cows trample one another, suffocating, gouging and blinding each other with their horns. The trucks careen down twisty, bumpy dirt and gravel roads and mountain passes, pitching the cows around, causing even more injuries. When they are unloaded, the cows who can still stand are pulled or forced to jump from the high truck beds, often breaking legs or pelvis. Those who have collapsed are dragged from the trucks and left lying while other cows are unloaded on top of them.

"…while the cows were being loaded, I could hear the gurgling of one cow choking on her own blood. The rope in her nose had been improperly placed, and with the constant tugging on it by rough handlers, as well as being tethered to her fellow cattle during the 12-hour march, it had ripped through her nose, and blood was pouring down her face."

Once inside the slaughterhouse, a huge concrete warehouse, the cows are dragged into the center of the barren room while their legs are tied up with a rope.
One of the slaughterhouse workers pulls back their throat and slit it. Right after him another worker slices a much wider cut. The workers don’t wait and hack their legs off, to start the skinning, many times while the cows are still alive.
All the other cows witness the whole process. They see each and every cow trying to breathe while their throat is fully open until they finally die.

Alligators and Crocodiles

Most of the alligators and crocodiles skins which are used for producing high-priced bags, shoes and hand watches, are originated in factory farms. Thousands of alligators and crocodiles are crammed into one coop constructed of concrete slabs in half-sunken tin-sided sheds, reeking of rotten flesh, waste, and stagnant water.
In these cages, a small number of aggressive individuals dominate the others, preventing them from moving around. It is estimated that 90% of the animals’ injuries are directly related to the oppressive nature of their environment. Their wounds often become infected as result of the contaminated water they live in. Besides wounds from fighting, they develop abnormalities and deformities because they can't walk or swim.

The common killing methods practiced on these farms are staggering. One method is to sever the spinal cord with a chisel, which can take five to eight blows with a mallet and merely paralyses the animal. Another is to cut their head off with a machete. Others use axes, baseball bats or mallets to try and smash the skull.

"…the worker wades into the stagnant waters and tossed out the struggling reptile. Other workers wielding an aluminum baseball bat repeatedly smash the animal over the head, even chasing after him to administer more blows as the wounded alligator tried to escape…the alligator continued to writhe and move minutes after he had supposedly been killed. The workers took out switchblade knives and slit the base of the alligator's neck…"

In another farm:"…one worker stood on the alligator's mouth, another on the tail, and the third used a hemmer and chisel to deliver 8 blows to the spinal cord…it took to the alligator TWO hours to die…"

It is estimated that more than a million animals endure these horrific conditions worldwide.

Cats and Dogs

It is estimated that about 2 million cats and dogs, mostly strays and "stolen pets", are tortured, murdered and skinned as part of the leather trade. The biggest producers are by far, Thailand, the Philippines and China which is the world’s biggest exporter.

Humans don’t mind wearing leather made out of "food animals", but are appalled by the thought of it coming from pets. Well, humans are excellent with cheap talk but pathetic with actions. Not just speciesists, but also hypocrites, they buy a lot of products made out of dogs and cats skins. The fact is that much of the leather comes from china and most of the dog leather comes from china (since the dog leather trade is dependent on the dog meat trade which is legal there). So besides that criticizing the Chinese for eating dogs while eating chickens, fish, cows, pigs, sheep and etc is hypocrite, it is even more absurd doing it while buying leather. Leather consumers are not only arguing against dog consumption while consuming other nonhumans who deserve not to be hurt just as much, but actually directly support dog consumption by consuming leather.

Dogs are rounded up from the streets and squeezed, more than 50 at a time, into a lorry for five days without food or water then they are murdered and become briefcases, car seat covers, drums, handbags, golf gloves and trimmings on a fancy coat. In a particularly grisly twist, the skins of brutally slaughtered dogs in Thailand are mixed with other bits of skin to produce rawhide chew toys for “pet” dogs. Thousands of dogs suffer the same fate each day.

Cats are stuffed into sacks and driven to the slaughterhouses, a journey that can last up to six hours in a highly crowded track, without food or water.
Only male cats are killed for their skins because the nipples of female cats reduce the usable size of the skin. So in case of scarcity of male cats, "collectors" drive to other cities to round up cats in the streets.

"…one by one the cats were hanged from their necks by ropes, they slowly and cruelly strangled while other cats watched helplessly. They did not scream, since the rope was pulled tighter and tighter as they struggled and slowly suffocated…the cats were then skinned, and the skins were thrown into ice water…"

Other Species

There are species, which are hunted specifically for their skin: Zebras, Bison, Water Buffalos, Boars, Deer, Kangaroos, Elephants, Eels, Sharks, Dolphins, Seals, Walruses, Frogs, Crocodiles, Lizards, Snakes and olive ridley sea turtles are captured and butchered for their skin. Another reason why leather is not a byproduct.

There is a reason why humans see leather as cool and sexy.
You can fight it and explain to people that it is wrong. That animals are suffering for it. You can tell them that they can buy synthetic materials instead. But leather is a lot more than a material that jackets are made of. Leather is status. It is a symbol of power and dominance.

Trying to convince people to buy synthetic fabrics is missing the point. Synthetic fabric is synthetic power symbol. Humans want leather because it is a symbol of power and domination.
Violence and control are a part of humans. The problem is intrinsic. And there is no "alternative" jacket in the world that can change that.