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How Horses Get Strong & Muscular Eating Grass. No Protein?

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Horses are one of the most muscular animals on Earth, but what’s amazing is that they don’t eat meat – they only eat grass. So how do horses get so muscular and strong eating nothing but grass?

Horses get all the protein they need for muscle growth and strength from plants. The secret lies in their digestive system. Horses have a single-chamber stomach where bacteria break down cellulose from grass to release nutrients like protein and sugars.

Horses are astonishing animals. They sleep standing up and can run amazingly fast, but one of the most surprising things about them is how they can develop such large muscles eating only grass!

Picture of a quarter horse that illustrates the large muscle development of horses.

How do herbivores get so big and strong?

Horses, along with elephants, rhinos, and gorillas, are herbivores, so how do they grow such large muscles on a plant plan diet? These animals have been eating plants for thousands of years, and their muscle growth has not suffered.

In fact, horses maintain their strength and muscles by consuming plants, where all protein originates. Protein is an essential macronutrient found in all living organisms. It is the building block of cells, tissues, and organs.

It is a key nutrient that helps to build, maintain and repair muscle tissue.; it provides energy for metabolism, thinking, and moving. These animals all have complex digestive systems that efficiently process food to extract the most nutrients out of every morsel of food. 

Picture of my horse grazing.

Horses extract protein from forage.

Horses are actually one of the most efficient herbivores on earth, with a digestive system that can convert grass to protein. They can do this because horses have evolved to be able to consume large amounts of roughage and then digest it in an incredibly short period of time.

A horse’s digestive system is fascinating and complex, and its eating habits are as well. Horses have small stomachs, and they require a lot of nutrition to keep them muscular and healthy, which means they need to eat a lot of the right kinds of forages throughout the day.

Horses’ stomachs are designed for this type of life: they eat all day long and in small doses, which keeps their guts constantly active to break down food. This helps create an efficient digestive tract that not only gets nutrients out as efficiently as possible but also makes them feel good while doing it!

So how do these amazing creatures get so strong and muscly while subsisting on nothing but greens? The secret lies within every single step of the digestive system.

Horses possess a unique feature in their stomach called a cecum, where bacteria break down plant matter, increasing their ability to extract nutrients from food and release amino acids to be absorbed by the small intestine.

Amino acids are the building blocks of protein used in muscle development and support many other important bodily functions. Horses’ stomachs also break down cellulose in plants into sugars, so there isn’t anything they need besides forage and water for sustenance!

Horses get protein in their diets through the consumption of forages, like grasses or hay. Even though most grass doesn’t have a lot of protein to offer them, there is some present-and a horse’s digestive system can wring out every last bit from what little is available.

Protein levels in grass vary depending on the type, growth stage, use of fertilizer, and time of the year. Protein in grass may range from 11-28%. Horses are very different from other grazing animals with their small single chamber stomach in contrast to the four-chambered kind found in cows and sheep!

However, the single-chamber stomach of a horse efficiently digests large amounts of forage quickly. A horse’s stomach produces vital amino acids from the forage, which is how horses build and maintain muscle on a grass diet. To learn more about grass for horses, check out this article: Grass For Horses: Why it’s Essential and the Different Types.

two.year .old
Picture of a two year old in training

How to put muscle on your horse.

A muscular horse is a happy one. But the process of putting muscle on a horse is not one that you should take lightly. A lot of time and patience is required to achieve the desired results. It’s important to remember, though, that this is an investment in your horse’s future health.

One of the most common questions that horse owners have is how to put muscle weight on a horse. There are many different factors that can contribute to an underweight or overweight condition in horses, but one thing you don’t want to do is ignore it and hope for the best. Here are four fundamental principles for putting muscle weight on your horse!

1. Start a deworming plan and have your horses’ teeth checked.

As a horse owner, you know that there are numerous ways to get your horse’s weight under control. However, if they have worms or bad teeth, these will make it much more difficult for them to obtain the necessary nutrients and calories vital for their health.

You may have the best weight gain plan for your horse, but other things can hinder progress regardless of what you’re feeding or how much exercise they get. Make sure to have a veterinary checkup and be on the right deworming plan so that no problem stands in the way of success for both you and them.

2. Increase your horses’ hay intake

Horses should consume about 2 percent of their body weight in hay. You can also increase this amount when you’re trying to make your horse gain more weight. Providing high-quality hay and mixing grass hay with alfalfa for extra calories is an excellent way to do so!

When feeding your horse, it’s essential to understand the difference between alfalfa and grass hay. Alfalfa is high in calories, so you should give it sparingly, but it’s a great food source for hard-working animals, especially when building muscle.

Grass hay, on the other hand, provides lower calorie levels, perfect for horses that are not being worked as often or need less food because they have a slower metabolism. I find the best way to feed hay when trying to build muscle is to provide horses with a mix of grass and alfalfa hay.

3. Add grain or supplements to your horses’ diet.

If you want your horse to grow big and strong, it must have all the building blocks they need. Commercial feeds or oats can help with this but should be introduced slowly because of how sensitive horses’ stomachs are.

Feeding too much grain without giving a horse time to get accustomed to it can cause lead to various stomach ailments such as colic, a hazardous condition with little hope of recovery if caught too late!

For underweight horses, putting on muscle weight requires a lot of calories. To get what they need from most hay would require them to eat twice as much as they typically do, and this is where grains and supplements come in. They provide more calories in smaller servings.

Commercial sweet feeds are sold in different protein levels, typically 10 percent and upwards. You can also add supplements to your horse’s feed to foster weight gain. Some popular ones are Manna Pro Cool Calories and Farnam Weight Builder Equine Weight Supplement. 

4. Incorporate exercise into your horse’s daily routine.

The importance of exercise for a horse cannot be overstated, especially if they are not getting enough out in the pasture. Introducing an exercise plan can help put healthy weight on your equine friend.

It is unnecessary to ride your horse every day, but you need to ensure it exercises at least thirty minutes a day. You can work the horse on a lunge line or put them on a walker or walk around with him/her. There are many ways for horses to exercise!

We know that exercise is vital to an individual’s well-being by stimulating muscle growth and can even help with mental health issues like depression. But what about how it benefits horses?

Horses gain the same benefits; exercise helps horses get stronger by building their muscles and lifts their spirits too. As an added benefit, it helps you bond with your horse by spending time together.

Exercise stimulates muscle growth. After the horses have exercised, their bodies build muscle and get stronger. Exercise also helps you bond with your horse by doing things together.

If you’re still having trouble putting weight on your horse after following these steps, talk with their veterinarian about other things that might contribute to your horse’s condition, such as medication side effects (such as those found in certain types of antibiotics) or medical issue.

Horses are massive animals with a lot of muscle, so they will need to eat a lot. They also require exercise and care in order to put on solid muscle weight. It can take time and patience before you see any results, but it will pay off long-term down the road if you put in the effort.

Picture of a thoroughbred stallion.


I’m sure many of you have heard the old adage, “you are what you eat.” Scientists and nutritionists have explored this concept for decades. It’s accurate in more ways than one, as what and how you feed your horse can determine how strong and muscular horses will be.

The grass and hay horses consume gives them all the protein, carbs, minerals, vitamins, and antioxidants they need to grow big muscles without any meat or animal products. If you want to put muscle weight back on your horse, you may need to add grain and supplements and make sure he gets plenty of exercise too.

Below is a YouTube video about how horses get muscular from a grass diet.


Can humans get protein from plants?

Humans can and do get protein from plants. The plant that’s often most associated with protein is soybeans – but there are other sources too! Almonds and pistachios both contain a good amount of quality proteins as well. And if anything, they make great snacks to curb those pesky hunger cravings!