Hi. My New Guinea pig Grace seems to be weeing a lot. Not really sure what's normal amount but compared to her partner she is drinking quite a bit more. She doesn't seem in pain and there is no blood, milky colour or bits. She is about 10-13 weeks. Any ideas? Should I be worried?
Guinea pigs can individually drink a very variable amount of water, from nothing to a lot and still be normal.
Generally we recommend to see a vet if your guinea drinks more than a bottle of water in a day on a regular basis or if the drinking habit suddenly increases markedly and stays high with no obvious connection to any recent climate changes (hot and humid weather/air conditioning/onset of indoors heating etc.) and only after you have made sure that there are no leaks, drips or blockages in bottle nozzle.
If you are really worried, see a vet for a good check over and a urine test re. invisible blood (urine infection), which can lead to a short term increased intake of water, but is usually accompanied by other symptoms like very strong stale smelling urine, red urine, squeaking when peeing and pooing.
Diabetes is best diagnosed via blood sample, which is not at all easy to get in a guinea pig and is best done by a specialist. Guinea pigs have naturally quite high glucosamine levels in their urine which has led to a surge of misdiagnosed diabetes for a while. Most cases of diabetes can be controlled via diet and will go away on their own again after a few months.
Your girl is to young for kidney failure, which is the other complaint connected with a high/excessive intake of water. Both issues usually make themselves known by a sudden large increase of water intake.
Milky colour in the urine is the natural way of excreting any excess calcium.