So, apparently, nothing like the French (in case that's originally French) 'Veau de la Pentecôte' (Pentecost Veal) has spread to Anglo countries...
That'd be with the 'Agneau de Pâques' (Easter Lamb) the only traditional meat eaten on those kind of traditional days that I can think about.
All of this became very old fashioned anyways and is mainly used now by marketing in order to boost the selling of or such products on such or such day.
Lol, they even managed to create a new one recently, the Saint-Martin!
And what is that?
The day of foie gras!
And why so??
Because Saint-Martin (who lived between 300-400 after JC) once gave his coat to a beggar!
And??
And that's the sense of sharing! 'which is exactly what we wanna promote, the foie gras is something to share with other people'.
All
here in that quite good bill about that for those who speak French.
Other than that, here there is also the traditional day on which you're not supposed to eat meat, so, still in most collective restauration stuffs (for kids, elders, or whatever) you gonna have fish on Friday. And all of this because Jesus would have been crucified on a Friday.