Rte 15

[Great-Wall]

24D. Only two bits of a stick required before the cow comes home ! (5) ?t?e?

[dannyk13]

Steer

[dannyk13]

st(ick) + eer(before)

[Calibax]

^In the sense of 'before' surely it should be ere not eer. Setter's error?

[Shenco]

24D Steer.
A second dictionary definition, if this helps :-
A steer is a bull that has been castrated.
Also, how sticks were used to achieve this..
https://amp.independent.ie/business/farming/castrating-bulls-tougher-in-the-past-involving-hallowed-out-elder-sticks-filled-with-bluestone-29565671.html

[fiction-factory]

Thanks. I am not sure the castration bit fits in here- just first two bits/letters of stick- and I don't think this explains where the eer comes from, unliss in Ireland they say eer instead of ere (or there was a 'sounds like' word omitted from the clue)