I’m sorry to hear this.
A whistling in the nose is usually, but not always, an obstruction in the airway such as from hay dust. Piggy airways are narrow and even the smallest piece of dust can produce quite a sound to their breathing.
Usually a good sneeze will clear the obstruction and all will be well.
However we cannot guarantee that that is what it is in every case. Therefore, if your piggy does not clear the sound with a sneeze after a few hours or if it clears and then returns, you will need to see a vet to have the chest checked.
Your piggy has been through a lot with his amputation that it is possible his immune system Is lowered and could make him more susceptible to opportunistic bacteria.
As a URI is a bacterial infection, it is perfectly possible (and does regularly occur) for one piggy to have a URI and for the other piggy(s) to never catch it. It simply means the immune system(s) of the other piggy is working and fighting it off successfully.
Therefore the assumption that it can’t be a URI because a cagemate is ok is not a safe conclusion to draw.
We would recommend you switch from the routine weekly weight checks and instead weigh him daily. This enables you to more closely monitor hay intake and to ensure he is eating which hay (hay intake cannot be gauged by eye). A piggy who is struggling with breathing can often reduce hay intake and then they need to be when syringe fed.
I hope he is ok
1 Statement
2 Emergency assessment and accessing vets
- How urgent is my guinea pig's problem?
- Finding an emergency vet
- Seeing a vet not familiar with guinea pigs (including lists of safe and dangerous medications)
3 First Aid care and easily available products
- General 'always have at home' stuff and comfort measures for very ill guinea pigs
- Improvising support feed; recovery formulas...