The difference between animal rights and animal welfare has been summed up like this:

Animal rights supporters believe that it is morally wrong to use or exploit animals in any way and that human beings should not do so.

Animal welfare supporters believe that it can be morally acceptable for human beings to use or exploit animals, as long as: the suffering of the animals is either eliminated or reduced to the minimum and there is no practicable way of achieving the same end without using animals.

For people who think like this, the suffering to animals is at the heart of the issue, and reducing the suffering reduces the wrong that is done.

Supporters of animal rights don't think that doing wrong things humanely makes them any less wrong.

Do animals need rights?
Animals don't need rights to deserve protection; a good moral case can made for treating them well and considering their interests that doesn't involve accepting animal rights.

Why animal rights?
Many animal lovers think animals don't just deserve protection in a paternalistic way. They say that animals have rights that must be respected.

Rights are much more important than interests, because rights impose a burden on others that the other parties must accept.

If animals do have rights then there are certain things that human beings should not do to animals, because doing them would violate the animal's rights.

This applies regardless of the cost to human beings. If humanity must suffer some disadvantage as the consequence of respecting animal rights, then that's the way it has to be.

Which animals have rights?
Nobody thinks that all animals should have rights - the question is where to draw the line.

One elegant phrase suggests that animal rights should be restricted to those animals that "have a biography, not merely a biology."

This means that only the higher animals would have rights - those animals that are conscious, can remember, and can form intentions and plan and act for the future.

Human rights versus animal rights
No-one suggests that animals should have all the same rights as human beings.

There are many rights that are entirely irrelevant to animals, such as freedom of religion, freedom of speech, the right to vote, the right to an education and so on.

The human consequences of animal rights
Accepting that non-human animals have rights requires human beings to accept that:

Accepting that non-human animals have rights restricts human beings, and may even cause people to die who might otherwise have lived.

For example, it means that human beings can't use non-human animals in medical experiments - even if this restriction will lead to the death of many human beings from a disease for which a cure might be discovered through animal experimentation.

Countless people within our ranks pin the label "welfarist" on people who are in fact rightists.
Which causes me to state once more a distinction that's constantly ignored:

Both terms, a.rights and a.welfare, connote a profound conviction , a conviction regarding an ultimate goal. They do not designate tactics, approaches, methods, campaigns, hands-on activism, etc.

The welfarist's conviction: There is nothing wrong with utilizing animals for human benefits. What is wrong is ruthless, callous exploitation. The welfare of animals matter, morally. We must be compassionate. We must avoid, as best we can, all unnecessary pain and suffering.

The rights conviction: Utilizing animals for human benefits is wrong. While compassion is a great virtue, our goal is simple: All institutions which commodify animals for human benefits must be abolished.

But given these definitions, it is simply wrong to apply the word "welfarist" to people who seek to reach the rights (i.e. abolitionist) goal through certain tactics, campaigns, legislative efforts, etc. designed to gradually erode the exploitative institutions.
Yes, we are bound to disagree on which approaches are effective, and we must debate the pros and cons among ourselves. Anyone opposed to campaign XYZ must articulate persuasive reasons, backed up by evidence, why XYZ will retard rather than hasten the abolitionist goal.

But again and again, abolitionist activists are being tarred with the label "welfarist", merely because they endorse interim, gradual, incremental measures, rather than go for broke with "all or nothing" campaigns. Thus, in specific campaigns (aimed at whales, or seals, or wolves, or primates, or battery cages) the activists may choose not to include "rights" or "abolitionist" rhetoric in their press releases or legislative efforts. That's a political tactic, and often an astute one.

One more thing:
The distinction between the utilitarian and the deontological view (Singer versus Regan) is a philosophical issue, which I believe should be debated only within the group of abolitionists. For practical purposes, both Singer and Regan can be regarded as abolitionists. Both want to abolish the vast animal exploitation enterprise as we know it