Daily musings

[Writerbyfire]

Do you think she knows
sat there in the grass                                     // It feels like you've reversed the lines just to satisfy the rhyme. I would reword this to give a flow of 
that when the day is done                                  thought. Commas would also help
she'll get kicked out on her arse?                    // Just say ass don't force a dialect conversion to fit the rhyme. I don't see why it should be arse without
                                                                      rhyming
Charitably she gives
life's liquid bequest to her,                             // bequest doesn't fit the register (i.e. high english vs. laymen speech) of the rest of the poem
and yet she's told she's lucky                     
to be kept in such fine fur!                             // If the poem is about the cow itself then this doesn't make sense. if the poem is about humans in some
                                                                      fashion then you need more clues and substance to that metaphor.
Do you think this mother knows
her young calf will soon be gone,
and who's the one to tell her                          // would you say to someone "to tell her to she it can't belong"  your mixing up the structure to try and fit 
to she it shan't belong?                                     the meter also register for shan't

Do you think she knows
that fine cow upon the meadow                     // register for upon
that what should have been a gift to her
has now become her shackles.                       // I get that the breaking of the rhyme is likely intended here for effect but it kind of just falls flat. 

You actually don't have a bad start here I think in points you are trying too hard for lofty or poetic language. This is something that you have to be very wary of in modern poetry. It must either be blended extremely well or if you're doing something like an imitation of or allusion to older poetry/speech. Using a higher register is generally an acceptable practice in poetry but it's still for the same effect as if you were writing an academic paper. You wouldn't write shan't in a paper so why would you use it in a poem. Usually when amateur poets do this, the answer is because they either think they can get away with it or they think that's the way poetry is supposed to sound. So to put it in other words its ok to use a modern high register but you must have a specific and clear reason to use an archaic high register. Other than that you have some areas where the meter and structure needs to be fixed. I would also change the title to better reflect the poem. You have a good method and plot. Other than the areas I mentioned it flows well and has a poignant ending.