can guinea pigs eat oat grass?

Can Guinea Pigs Eat Oat Grass and Oat Hay?

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It’s springtime, and I wanted to plant a section of my garden just for my guinea pigs. And of course, it won’t be complete without some fresh grass. But can guinea pigs eat oat grass and oat hay? Well, you’re in the right place! By the end of this article, you’ll know if oat grass for guinea pigs is healthy, how often and how much is good, and so much more.

Even though I have a whole backyard with lots of grass, I didn’t realize that type of grass was extremely high in calcium and contributed to the bladder stones in my guinea pig. So I set out to find types of grass that my guinea pigs can safely eat. But that grass has to be easy to find in garden stores too.

Searching in several garden stores, I came across some oat grass seeds. After hours of researching, here’s almost everything about oat grass and hay for guinea pigs.

What is oat grass?

Oat grass, also known as Avena sativa, is the young and tender shoots of the oat plant. This crop is suitable for both animals and humans. It is ideal for feeding animals like cats and guinea pigs and is commonly grown as a cereal crop. Oat grass is also rich in fibre, vitamins, and minerals, therefore making it a great addition to your piggy’s diet.

Can guinea pigs eat oat grass?

Yes, oat grass is a popular choice for guinea pigs due to its high fibre content, which aids in digestion and keeps their teeth healthy. Additionally, it provides essential vitamins and minerals, making it a great occasional treat. However, it’s important to introduce it gradually to avoid any digestive issues.

Can guinea pigs eat oat hay?

Yes, although oat hay is not commonly used to feed guinea pigs, it can be a great addition to your guinea pig’s diet. It provides a tasty source of fibre and helps maintain their dental health. However, it’s essential to make sure that the hay is fresh and free from pests or mould.

can guinea pigs eat oat grass seed

Can guinea pigs eat oat grass seeds?

Yes, oat grass seeds are safe for guinea pigs if you feed it in moderation. The seeds contain essential fibre and nutrients, but too many seeds can lead to digestive issues or weight gain. That’s why it’s best to feed it to your guinea pigs in limited quantities as a treat instead of as a staple part of their diet.

When choosing oat grass seeds to grow for your guinea pigs, it’s recommended to pick ones that are non-GMO, and better yet, organic to avoid chemical residues.

Nutritional facts in oat grass for guinea pigs

The nutritional composition of oat grass can vary slightly depending on factors such as growing conditions and maturity at harvest. However, here is a general approximation of the nutritional values of oat grass per 100 grams, or about 1 to 1.5 cup loosely packed:

  • Calories: 50-60 kcal
  • Protein: 3-4 grams
  • Fat: Less than 1 gram
  • Carbohydrates: 8-10 grams
  • Fiber: 1-2 grams
  • Calcium: 50-100 milligrams
  • Phosphorus: 50-100 milligrams
  • Potassium: 300-400 milligrams

A side note, the value of vitamins A, C, and K in oat hay varies, depending on the maturity and growing conditions of the plant.

As the oat grass matures, its vitamin A and C content may decrease. So when you’re picking oat grass, it’s best to choose younger plants. On the other hand, mature grasses tend to have higher levels of vitamin K.

Other factors that can change the oat grass’s vitamin and mineral content include the amount of sunlight and water it has and the soil quality.

oat grass for guinea pigs

Nutritional benefits of oat grass and hay for guinea pigs

Oat grass is an excellent source of dietary fibre essential to keep your guinea pig’s digestive system properly functioning. The high fibre content helps regulate bowel movements and prevents common digestive issues like constipation and diarrhea.

Additionally, the fibre in oat grass supports dental health by naturally wearing on your guinea pig’s teeth as they chew. This helps prevent their teeth from overgrowing.

Oat grass also contains vitamin C, which is really important for guinea pigs. They can’t make vitamin C in their bodies like we can, so they need to get it from their food. Vitamin C helps their bodies stay healthy by strengthening their immune system, helping them heal when they get hurt, and making it easier for them to use a mineral called iron, which they need to stay healthy too.

Moreover, it’s packed with vitamins and minerals that guinea pigs need to stay strong and healthy! It has vitamins A and K, which help keep their bones healthy and their muscles working well. Plus, it has minerals like calcium and potassium, which are like the building blocks for their bones and muscles.

Adding to that, oat hay has a great calcium-to-phosphorus ratio, which is 1.3:1. That’s less calcium than Timothy hay, which is 2.2:1. For reference, a good Ca:P ratio is 1.3:1 to 1.6:1.

can guinea pigs eat oat grass

Oat grass risks for guinea pigs

While oat grass can be a nutritious addition to your guinea pig’s diet, there are some risks and considerations you need to keep in mind.


Even though oat hay is nutritious, it has a higher calorie and sugar content compared to other hays, making it not suitable to eat every day for the average piggy. Too much oat hay can lead to obesity, so it’s best to consult your vet about it before incorporating oat hay as a large part of your guinea pig’s diet.

On the flip side, if your goal is to help your guinea pig gain weight, oat hay can be a good choice to add to their diet.

Pesticides and mold

Another consideration is the source and quality of the oat grass. If oat grass or hay becomes damp or mouldy, it can be a risk to your piggies. And you don’t want that, because it can cause digestive issues or respiratory problems.

To prevent this, make sure to provide fresh, clean, and pesticide-free oat grass to your guinea pig. Avoid using grass from areas that may have been treated with chemicals or exposed to pollutants. Also, always be cautious when you’re foraging for oat grass because it may be contaminated with harmful substances.

If you’re buying hay and grasses instead, remember to get them from reputable suppliers who prioritize organic or pesticide-free cultivation practices.

guinea pigs eating oat hay

Can guinea pigs eat oat hay every day?

No, oat hay is not suitable for guinea pigs to eat every day, because it is higher in calories, protein and hat than hay compared to other hay that they can eat every day. It’s best to feed oat hay as a treat to your guinea pigs instead.

Regarding how often you should feed oat hay to your guinea pigs, a good rule of thumb is to feed it a small handful 1-2 times per week.

Is oat hay a good substitute for Timothy Hay if I have allergies?

Oat hay is a cereal crop, and according to a study, these grasses are autogamous, This means that they produce very little pollen and the size of the pollen is larger and heavier too, making it harder to float around the air. Therefore oat grass and hay are harder to cause allergies in people compared to other grasses like Timothy. However, that doesn’t mean that humans can’t be allergic to oat hay as well.

But because oat hay is higher in calories and sugar, you shouldn’t feed it to your guinea pigs daily.

Oat Hay vs Timothy Hay

To summarize, oat hay contains slightly higher levels of protein and sugar and has a sweeter taste. Timothy hay has a larger leaf-to-stem ratio and it has a softer texture. Timothy hay is more suitable for small pets to eat and is available year-round.

can guinea pigs eat oat grass and oat hay

Is oat grass the same as cat grass?

Cat grass is like an umbrella term for grasses that cats can eat. That includes barley, wheat, rye and oat. So oat grass is a species of its own, but when you see the term cat grass, it sometimes has a combination of all of them.

Fun Fact

As temperatures rise and CO2 levels increase, oat grass grows bigger and packed with more nutrients like iron and calcium.


Oat grass is safe for guinea pigs in moderation, and it makes a great grass choice for your guinea pig garden.

To fill your garden with more yummy plants for your guinea pigs to enjoy, planting cauliflower and bell peppers can be a good idea. But remember to look out for toxic weeds or weeds that should be fed in moderation, like dandelions.

Keep in mind that if the weather is too hot or cold, it’s best to plant it in a wide shallow seed starter tray with potting mix or soil indoors instead. Your guinea pig’s safety and comfort should be the first priority.

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