Delia

[dukealien]

It was not the brightest morning,
Not a day to play in the field,
You’re a bit sick, you’ll soon be healed,
Not to worry! just a warning.
 
Come to see you, all is so sad,
You wage your tail, yours eyes are bright, should "wage" be "wag?"  See below...
Behind that spark I feel a fight,
Not to worry? I’m going mad.
 
You lay down, head in my hand,  strictly speaking, "lay" should be "lie" here, also one syllable short
Your velvet ear fits like a glove,
In one look can be so much love,
You’re so brave, should I take a stand? a little unclear here
 
I hate myself, still get a lick,
But stuck like a bear in a trap,
Tell you “Let’s take a little nap.”
And the vet played his dirty trick.

The story here is clear and affecting (nicely paced).  The rhyme scheme is neatly and accurately carried out.

Except for the line noted above, all have 8 syllables.  There is no established meter - which, in my experience, is unusual in a fully rhymed poem like this - but the natural rhythm of the lines when spoken fits the simple, developing theme.

My notes (above) on word usage are provisional:  "wage" rather than "wag" could be waging a battle for life, and "lay" would work in strict grammar if there were no comma in mid-line; using "lay" for "lie" (lay down a bone, lie down to rest) is common usage and fits this plain-spoken poem.  You might try "wag" and "lie," though, and see how they sound to you.

The line flagged as unclear caused me a little confusion:  what stand is suggested?  Bravely telling the dog it's about to be put to sleep instead of lying, or telling the vet not to do it?  Taking a stand (outside, not watching) didn't make sense to me, either, but I may be missing the intent here.

This is quite nice, the story develops well, and the varied rhythm makes it more conversational than lyrical.

One irrelevant note:  capitalizing the first word of each line, while (because?) traditional, is somewhat disapproved on this site except where grammatically required.  This seems to me less style than fashion, but you might try de-capitalizing this poem to see how it works for you.