Guinea pigs' food requirements are fairly simple, but it is easy to get them wrong and end up feeding your pets foods which don't provide them with enough essential nutrients and minerals. Worse still, by giving them the wrong diet, they may become obese or seriously ill.
The following food list provides a guide to the things you should be feeding to your cavies, what you should avoid, and any special requirements you may not be aware of.
Pellets or Dry Food Mix
A high-quality pellet or dry food forms the basis of a healthy guinea pig diet. Supplemented with plenty of fresh vegetables, hay, and water, your cavy will have all the nutrients it needs.
Pellets are considered better than mixes, and are available in two types. Alfalfa hay-based pellets are ideal for young and pregnant pigs because they contain a higher level of calcium. This can cause bladder stones in adults, so you should switch your pets to a Timoty hay pellet at around 12 months old.
Dry food mixes aren't as good as pellets because they allow your cavies to pick and choose what to eat, and leave the rest. This can result in a unbalanced diet. You should also avoid mixes which contain nuts and seeds, as the husks can get stuck in your pets' teeth and cut into the roof of their mouth.
Most pet stores sell a variety of pellets and mixes, from suppliers such as Oxbow, Wagg, Gerty, and Burgess Excel. Avoid the cheap, loose mixes sold in buckets and buy a quality, sealed, brand-name food instead.
Each of your guinea pigs will need between half and one handful of dry food per day, but adjust the amount you give yours according to what they eat. Serve in a heavy ceramic bowl, as these are less likely to be tipped over.
These are the best source of vitamin C and other nutrients, and also help to keep your animals a varied and interesting diet. Each pig should be given 3 to 5 matchbox-sized portions of fresh vegetables each day.
Before serving, wash the vegetables thoroughly, remove any seeds, and cut into bite sized chunks. Many veggies come with leaves attached, which your guinea pigs will also enjoy.
Favourites include bell peppers, broccoli, and Romaine (cos) lettuce. Never feed your pets potatoes, rhubarb, or iceberg lettuce as these can all be potentially toxic.
Any vegetables you give your pets will rot quickly, so any leftovers should be removed from their cage after an hour or two and thrown away.
Fruit is much higher in sugar than vegetables and so should not be given to your pets more than once or twice a week. Guinea pigs will eat almost any type of fruit, so try a few to see what yours prefer. Apples seem to be particularly popular, but try to get the more 'flowery' varieties as these are less acidic than crunchier ones.
The only other type of fruit to be wary of are grapes, as it has been suggested that they might cause kidney disease, although this has yet to be proven.
Again, fruit rots very quickly, so throw it away after an hour or two.
This is an essential guinea pig food, and you should give your pets a constant supply of fresh, clean, dry hay at all times. It helps to regulate their digestion, and they also grind it between their teeth to keep them short (guinea pig teeth keep growing throughout their life). Your pets will also use it as a bedding material, so make sure they have lots, and refresh it regularly.
There are two main types of hay, Alfalfa and Timothy. Alfalfa is best for growing and pregnant guinea pigs, but its high calcium content can cause bladder stones in adults. To prevent this, once your pigs reach adulthood (at about 12 months), you should switch them on to Timothy hay.
Although this is not essential, guinea pigs find it really tasty, and it also provides several important vitamins and minerals, including vitamin C. You should always use fresh grass which is free from herbicides and other chemicals. Don't use grass which has been cut by a lawnmower - tear it out of the ground instead. As with vegetables and fruit, this rots quickly, so remove it from their cage after one or two hours.
During the summer months it's a great idea to put your guinea pigs outside in a run. This way they can have an endless supply of fresh grass, and get plenty of exercise at the same time.
Guinea pigs cannot produce their own vitamin C, so it must be provided in their diet. A deficiency can lead to serious diseases such as scurvy, bone deformations, and immune system problems. If you are giving your pets plenty of pellets, vegetables, and grass, then they should be getting all the vitamin C they need, but if not you can give them a supplement.
Vitamin C supplements come in tablet form and as water-soluble medicines. However, vitamin C degrades quickly in water and sunlight, so always choose the chewy tablets. This also makes it easier to ensure that each pig is getting the right amount, and they love the taste as well.
Water is essential to a number of important bodily processes, so make sure your cavies always have plenty of fresh, clean, cool water to drink. You should change it at least once a day, and more often in warm weather. Check the level frequently throughout the day and top it up when required.
Water bowls are prone to being tipped over, and quickly get filled with bedding, so water bottles are considered to be better. Whichever you use, be sure to clean it thoroughly several times a week (with a bottle brush if necessary), and check it periodically for leaks and to make sure the spout is working properly.
Guinea pigs don't crave treats like humans do, so there's really no need to give them anything special. In fact, typical human treats such as chocolate, cakes, and biscuits are toxic to a guinea pig, and can cause serious health issues. The best treats for cavies are fresh vegetables, fruit, and fruit tree twigs.
They are herbivores so never give them anything containing meat or dairy products - they won't be able to digest it properly.
Introducing New Foods
Guinea pigs can respond badly to sudden changes in their diet, so it's important to introduce new foods gradually. Begin by giving them a little bit of the new food alongside their normal diet so that they can get used to it. Over time, gradually increase the amount of the new food and decrease the amount of the old.
They can be slow to try new things, but persevere and eventually one of them will have a nibble on the new food. Once one does, the others tend to follow. With a bit of luck they will like this new taste, but if they don't then don't worry, as there are plenty of other things for them to try. Guinea pigs are a lot like humans in that their tastes vary greatly, so what one won't eat, another might love.
Tracking What They Eat
Keep a mental note of how much food and water your pets are consuming. Gradual variations are natural - for example they will naturally eat more as they get older, and will drink more during the summer months. However, sudden changes can be an early sign of illness.
You should also keep track of your pigs' weight. Using kitchen scales, weigh each of your pigs weekly and write it down in a notepad. If you notice any sudden changes or long-term trends, this may be a sign of an underlying problem, so take your pet to the vet, and be sure to take your weight diary as this will provide the vet with essential background information.
A guinea pig's nutritional needs are not complicated, but you must be very vigilant and be sure that you are providing them with everything they need at all times. By carefully selecting your guinea pigs' foods, you will help to keep them fit, healthy, and happy. In return you will find your pet more alert and playful, which benefits you as well.