As someone who has raised beef cattle (here in Oklahoma) I must say the TFD is (unfortunately) mistaken, (at least here in the U.S.) Most cattle fall into one of two varieties, Beef and Dairy (there are also some breeds that are almost exclusively show cattle) The most popular (and common) Beef varieties are Angus, Limousine, Herefords, Longhorn; This list, including cross breeds (for instance, limangus, what I raise, is a cross of limousine and angus) and constitutes somewhere around 90% of beef production with in the US. (not include 'beef' used for things like dog food). I would consider that list to be in descending order of beef quality (but that is a matter of opinion...)
There are several varieties of cattle which are raised for dairy production, and these do not generally produce quality cuts of meat, but do produce copious quantities of milk. These breeds are led by Holstein-Friesian, Brown Swiss, Guernsey, Ayrshire, Jersey, and Milking Shorthorn.
Buffalo (or Bison) is a separate breed altogether and is no longer all that exotic. I regularly use bison to make chili.
Yes, cows are 'females' but not all cows are heifers, a heifer is a female that has not yet given birth to her first calf .
And @Scivitri while feeding and ranging cattle do make a difference the driving force in beef flavor is still the breed. I can tell the difference between breeds by flavor but the difference from feeding and ranging is really more about tenderness and texture.
I don't think you can make a Beef Wellington without the obligatory mushrooms, it essentially becomes something else.
The whole concept behind beef wellington is to keep the meat juices in by being surrounded by pastry but there's no reason why you shouldn't omit the mushrooms for something else. I really can't think of any other food substance that would replicate the flavour of mushrooms without being mushrooms other than truffle.
I would try something like a pork/onion sausage meat stuffing and being the time of year it is, perhaps with chestnuts as a possible alternative, either surrounding the beef or inside it.
Best Answer
I don't know your exact prep but the best thing you could do is bring your dough to a completely thawed state, store bought will work fine. Make sure you beef is at room temperature before doing a quick sear, this will not only add flavor but will give you a layer of protection. Another problem that can occur is the puff pastry releases some steam and it needs some way to escape. After you have wrapped your piece of meat, take a knife and make small slits in it with the tip of a sharp knife. This will help release the steam and should take away the moisture. 425 degrees would be a good temperature to cook at and you should hit your ideal around 40 to 45 minutes. Hope this helps and let me know how to it turns out.