Horse not wanting to stretch or jump uphill

[MissTyc]

I have a 13.2hh pony that is on full loan to an excellent knowledgeable family - they keep at my yard so always in sight. Pony is not a world winner, but is regularly placed at unaffiliated 2ft6 and generally is a cheerful, schoolmaster type.

Loaners came to get me today to express concern about pony - she's reticent, esp when asked to stretch (snatches the reins). I trotted her up, then lunged her on a tiny circle on the concrete and she appears sound all round. Ears pricked, strides out, happy... I then hopped on for a test ride and she feels completely normal, except when you ask her to stretch, she backs off the leg and just won't do it. They have said that she is jumping on the flat and downhill absolutely fine, but uphill doesn't want to jump at all and has started refusing (only uphill).

What would be your first thoughts?
I am thinking maybe something back-related.
Might have to get a loss of performance work up, but seems a bit premature so will give her 5 days off and then maybe do a bute test. I quite like this little mare. She's only 10, so I will definitely investigate.

 

[Cuppatea]

back.....

 

[sariska]

I'm 99% sure it's her back. I would really be getting it done asap, because the sooner you get it looked at, the easier it is to fix.

 

[TGM]

Has pony put on weight or broadened out at all? If so, it is possible that the saddle may now be pinching which can have the effects you describe.

 

[Shysmum]

back and/or saddle..

 

[MissTyc]

Thanks - confirms my thoughts. Good point about the saddle, as well. She's not changed weight to my eye, but then I see her every day so she may well have put on/muscled over the last few months (in fact I expect she would have after a lazy winter!)

 

[aduffield]

Looks like a bad back. I could tell when my old horses back had gone because she could jump uprights but not spreads as she couldn't reach. Hope this helps.