@alex @technomancy @clacke not sure if you can even get it from testicles or semen (there seems to be Internet rumours about both), but if you can it must have been much more expensive than synthetic taurine, so they would surely have advertised it in that case.
Side note: the animal in the original name of the brand (grating daeng), and the animal on the logo, is not a bull of cattle but a gaur: https://en.wikipedia.org/wiki/Gaur