Economically speaking becoming vegan is completely futile and may actually damage the cause more.

You buy meat and have a choice of two local farms. As you drive past one, you see that the cows are well fed and well looked after. You drive past the other and see they are thin and sick. Naturally, you'll buy from the better condition animals, simply because the other doesn't look healthy and that won't taste or be as healthy for the consumer.

The poor quality farmer has two choices. To lower the price of the beef to a point where it becomes loss-making, or to increase quality to the level of the good farmer.

Now you decide to become vegan and not buy from either farmer. This means both farmers have to cut corners to produce meat at a price they can sustain and that the remaining buyers will buy at. (or they can raise prices and people will go to alternate meats and substitutes).

By withdrawing funding for the good farmer and removing the incentive for the poor farmer to improve you actually negatively impact both farmers and in consequence the remaining consumers.

The best option is to buy as much meat as you want from the good farmer enabling him/her to expand and potentially buy out the poor farmer or send a signal to the poor farmer that they could do better in terms of finance, reputation, and animal welfare if he upped his game.

However, what veganism really does is tell the world you've been sucked in by left wing ideals that run contrary to nature and are ultimately destructive to everyone, including the livestock.