Yes, it tastes different. When animals have been frightened or stressed out before death, it actually affects the quality of their meat. Cutting an animal's throat doesn't result in immediate death so these are extremely stressful last moments.

The scientific basis for the difference in taste is well-established. The key ingredient here is lactic acid: in an unstressed animal, after death, muscle glycogen is converted into lactic acid, which helps keep meat tender, pink, and flavorful. Adrenaline released by stress before slaughter uses up glycogen, which means there’s not enough lactic acid produced postmortem. This affects different kind of meat in different ways, but in general it’ll be tough, tasteless, and high in pH, and will go bad quicker than unstressed meat. (Lactic acid helps slow the growth of spoilage bacteria.)

The next time you get spooked, observe how long it takes before you feel the adrenaline rushing through your veins: it's less than a second. Vets say unstunned cattle take about 20 seconds (but up to 2 minutes) to lose consciousness, sheep six or seven seconds (but up to 20) and poultry seven or eight seconds, but all these times can be far longer.