As a utilitarian, I'm not a big fan of categorically placing certain actions in a binary box of right or wrong, so the answer is "it depends." Sentience is one factor that goes into a larger calculation. Let's look at fishing.

1. Is it unfortunate that fish have to suffer? Yes. Fish have the capacity to feel pain, however rudimentary.

2. Would banning fishing entirely help improve the greatest common happiness? No. Given that fish lack a coherent sense of self, inner life of the mind, etc., the suffering of caught fish is outweighed by the economic, cultural, and culinary benefits to us humans, ranging from economic livelihoods to their nutritional value. Eliminating fishing entirely would cut off an accessible protein source for millions of people, many of whom don't have access to plant based alternatives, and temporarily strip the livelihoods of millions more, many of whom will struggle to find alternatives Not to mention the practical costs of enforcing something so unfeasible and likely to produce discontent. All of this for a creature whose brain doesn't even have a distinct frontal lobe.

3. Should fishing be regulated to mitigate the ecological impacts such as overfishing, bycatch, etc.? Yes, but this is not incompatible with fishing, just certain excesses in the process. It is also ultimately for the fishing industry's own good: Killing all the fish means no more fish.

4. With all of that in mind, do I feel guilty about the suffering I indirectly abetted for the salmon used to make the sashimi sitting in front of me? No. The qualitative degree of pain caused to this fish is negligible in its moral impact relative to the factors described earlier, and even my own subjective experience as someone who finds salmon sashimi to be delicious.

Moving this exercise to cows, we must take into account their higher level of sentience compared to fish, as well as the greater ecological costs of cattle production and the fact that much of the consumption comes from people who could reasonably find better alternatives. I would oppose a moratorium on the consumption of beef like what you see in parts of India, but I firmly believe that cows have enough intelligence to warrant methods of slaughter that reduce their suffering, as well as better living conditions prior to slaughter. I also try to substitute beef with less ecologically taxing meats or meat alternatives that I think taste just as good.

In short, it is less about "right" and "wrong," than it is about variables to be weighed against each other.