Actually, it's not the strings that are made out of horse hair. It's the hairs on the bow, where you drag it across the strings. In the old days, the strings themselves were made out of cat gut. Over the past 20 years or so, they have switched over to mostly synthetic bow hair and stainless steel strings. Those who do still use real horse hair for the bows are much kinder in their collection. The tails are not yanked out, they are brushed as if you were grooming your horse, and then whatever is loose and caught in the brush is cleaned, processed, and used to make bows. Sorry, didn't mean to go on and on, lol.