In the usage I'm familiar with, "cow" specifically means a female who has given birth. As opposed to heifers, who haven't. The general term for any member of the species would be cattle (both singular and plural). You might use "cows" to more generally mean any female cattle, but using it to include males of the species, too, would be understood as humorous.
What is your source for this information? I have worked with meat for years and have never heard anyone react with humor to steers or bulls being referred to as cows. Go into a butcher shop and ask where their cows are raised and they will answer you without hesitation. Ask them without using the word and they will readily refer to beef as having come from a cow.
EDIT: Even googling "beef cows" provides a wealth of contradictions to your statement.
My source for this information is how the language is spoken among members of my social circle. Which admittedly doesn't include any butchers, just dairy farmers. Maybe our social circles are different. That's regional variation for you.
No it does not in agriculture. The toilet is not for bulls, simply because the bulls are already steaks. Farmers keep only a few of them. Just enough to fertilize the females.
In the video, the farmer demonstrates how petting the vulva gives the cow a pissing reflex. That's not exactly applicable to bulls -- and if it were in a similar male area I'd spitball that you might end up with semen instead.
