Butternut squash can be fed to your guinea pig but it isn’t the kind of vegetable you should feed to your pet too often as it is quite high in oxalic acid.
Butternut squash (known in New Zealand and Australia as butternut pumpkin or gamma, is a winter squash and a bit like pumpkin in taste and texture. Although we call it a vegetable, it is actually a fruit and has a sweet nutty taste. The riper the squash, the sweeter the taste will be.
The squash, which grows on a plant close to but over the ground, has a distinctive shape with an elongated top and a more bulbous bottom half. The flesh is a bright orange color and in the bulbous part of the fruit are the seeds which you can easily scoop out with a spoon. Widely available at most grocery stores they are in season in the UK between September and December.
Some like squash and others don’t so if you give it to them and they’re not interested it is worth trying just a small piece occasionally as they may get used to the taste. However, ours are not keen on it so we don’t feed it to them as there are plenty of other vegetables which are a lot better for them.
When we’ve fed them to our piggies, we’ve left the skin on (after a thorough wash) but they do tend to eat the flesh and leave the skin.
Rather than butternut squash, carrots are a good alternative that are both cheap to buy and a vegetable that most guinea pigs love. The majority of their vegetables should be green as these are generally preferred and better for them such as red and green leaf lettuce, parsley, cilantro, kale etc).
So if your guinea pig likes it, just a small piece a very occasionally is plenty.
Below is the nutritional value per 100g of butternut squash