According to Cristina Odone in the Torygraph, Britain 'is set to become a country that prizes a cow more than a Jew, an ox more than a Muslim'. This is because, apparently, ritual slaughter will probably be banned in the UK in the near future, meaning that neither Kosher nor Halal meat will continue to be produced here. Jews and Muslims will have to get their meat from elsewhere, and this is evidence, according to Odone, that cows are more important than Jews in modern Britain.
Of course, no one is forcing Jews to be slaughtered, humanely or otherwise, so Jews' lives are not being valued less than cows' lives. Instead, the lives of cows are held to be more important than ritual prescriptions, which seems like a fairly obvious moral principle. They are more important, and that's that.
Religious freedom isn't absolute: human sacrifice is seemingly just as ancient as animal sacrifice and has been practiced widely by lots of different human groups, but if a sect in the UK wanted permission to kill human beings during mass, that permission would rightly be denied. Human life is more important than adherence to ritual, and while I can see some of the appeal of certain Aztec religious concepts, I wouldn't want to live in a society that valued superstitions above lives and allowed adherents of Aztec religion to kill people during religious services.
Likewise for animals' lives. It seems that most animals feel pain and, given this, steps should be taken to minimise their pain. Religious justifications are simply not enough to override this basic moral principle. It isn't that the lives of religious people are worth less than the lives of cattle, but rather that the lives and feelings of cattle are, to moral people, worth significantly more than the desire to kill them in inhumane ways for superstitious reasons.