Proteins are the building blocks for the equine body, something that you probably already know. But how does this process work, exactly? What are proteins, and why are they so important for muscle building and muscle recovery? In this Science Sunday, we take a closer look at the topic of proteins.
Just what is a protein?
Proteins are complex organic connections that are essential for the building, structure and function of cells, tissues and organs in all living organisms. They consist of amino acids that are linked together by chemical bonds. Amino acids are the building blocks of proteins and there are 21 different types of amino acids, arranged in different combinations and sequences to form a wide variety of proteins.
Proteins have different functions in the equine body. They help in muscle development and recovery of tissue like muscles, bones, and organs. Proteins also play an important role in regulating chemical reactions, transporting substances through the body, supporting the immune system and transmitting signals in the body (such as hormones).
In short, proteins are very important because they help the body to function. They are necessary for the body’s growth and recovery processes and play a role in maintaining good health.
A horse’s body cannot produce essential amino acids
The terms “essential” and “non-essential” amino acids can be confusing. At first glance, the terminology would imply that horses don’t need non-essential amino acids, but this is not the case. The terms refer to the source from where we get them, and not whether horses need them. To produce proteins, every horse needs all amino acids – both essential and non-essential. The difference lies in the fact that essential amino acids are the ones that the body cannot produce and so the horse must get them through feed. Non-essential amino acids are the ones that the body can produce itself.
Here are the nine essential amino acids that horses must get through feed:
- Lysine
- Methionine
- Threonine
- Tryptophan
- Valine
- Histidine
- Phenylalanine
- Leucine
- Isoleucine
Here are the amino acids that the equine body can produce:
- Glutamate
- Glutamine
- Aspartate
- Asparagine
- Tyrosine
- Cysteine
- Glycine
- Proline
- Alanine
- Serine
- Selenocysteine
- Arginine
The unique amino acid formula
Proteins consist of amino acids that are linked together by chemical bonds. These amino acids form long chains and the order and combination of the amino acids determine the structure and function of the protein. There are 21 amino acids in all; these can be arranged in different ways to form a wide range of proteins. Each amino acid chain forms a unique protein with specific properties and functions.
The equine diet plays an important role in providing the body with the amino acids needed to produce new body proteins. Each protein source contains different amounts of certain amino acids, with its own unique amino acid profile. This means that different protein sources deliver different amino acids. The type and quality of the protein source will affect how well the horse’s body can build new proteins. It is important that horses be given a balanced diet with adequate essential amino acids to ensure that they can make enough protein for growth, recovery, and other bodily functions.
In short:
- A protein is a chain of amino acids
- The body needs all 21 amino acids
- Essential amino acids must be obtained through feed
- Each protein has a unique amino acid profile
- The quality of the protein source in the diet will affect how well the horse can build new proteins
Why do horses need protein?
Water comprises the largest part of a horse – about 65%! But did you know that when we look at nutrients, proteins come in at number 2? At about 16%, protein is the most abundant nutrient in the body. Compare this to fat (12%), minerals (3%) or carbohydrates (1%), and you see that protein is an important part of the ration. Proteins are called “the body’s building blocks” for a reason. Amino acids are necessary for making new proteins in the body – the building blocks for:
- Body tissue
- Blood, organs, cells, muscles, skin, hair, hooves
- Fetal growth, lactation
- Enzymes, hormones, transport
- Immune cells
- And more!
If a horse isn’t getting enough protein, this will have considerable effects on many metabolic processes. Long term, this can lead toweight loss, muscle atrophy, reduced feed intake, poor coat and hoof quality, stunted growth in young horses, and weakened immune system.
From feed to body proteins
Because forage forms the largest part of the ration, horses get a large part of the protein they need every day from their hay or grass. Keep in mind that the quality of protein found in forage is often lower than that found in concentrates and supplements. For horses with higher protein requirements (due to exercise, growth, pregnancy, etc.), it is best to supplement the ration with a concentrate feed, balancer, or supplement that contains a better-quality protein source.
But how does the horse’s body convert these dietary proteins into amino acids that it can then use? Proteins from feed come in long, complex chains. The feed passes into the stomach where the proteins are exposed to gastric acid and enzymes such as pepsin. The gastric acid is important for breaking down the complex protein chains so that enzymes like pepsin can break the chains into smaller components.
The feed then passes into the small intestine, where it is digested further. Here the peptides are broken into individual amino acids by enzymes such as trypsin and chymotrypsin, which are produced in the pancreas.
The amino acids are then absorbed by the intestinal wall and enter the bloodstream. This absorption process takes place via active transport and diffusion, whereby the amino acids are absorbed by the cells of the intestinal wall and passed into the bloodstream.
In the blood, the absorbed amino acids are transported to various tissues and organs in the body, where they are used for the building and regeneration of new proteins.
However, not all protein is digested in the same manner. If some of the protein is undigested in the small intestine, it might end up in the large intestine where it will be fermented by the microbes. In this process, the end product is not a highly absorbable amino acid, but rather ammonia. Therefore digestion of protein in the hindgutdoes not contribute to amino acid absorption. To use the protein as a building block, it must be digested in the small intestine and not in the large intestine!
How do you ensure that? By looking at protein quality! We ‘rate’ the quality of a protein by its digestibility in the small intestine as well as its amino acid profile. Because only protein that is digested in the small intestine delivers the amino acids (building blocks). The higher the digestibility of a protein, the more amino acids it will deliver to the horse. Here the source of the protein is important. Protein sources in concentrate feeds are typically selected to have higher digestibility than for example protein from forage. Secondly,the amino acid profile, determines which specific amino acids are delivered. The closer the amino acid profile from the feed matches the horse’s own amino acid profile, the more efficient feed amino acids can be converted to body protein and the more benefit it will brings to the horse.
In short:
- Protein is the most abundant nutrient in the body
- Proteins are the body’s building blocks
- Protein is found in every tissue and every cell in the body
- A protein deficiency has serious consequences for a horse’s health and performance
- High-quality protein = highly digestible and good amino acid profile
- Higher-quality protein will provide more benefit for the horse
- A good amino acid profile should match the horse’s amino acid requirements
Forage and concentrate feeds as protein sources
Now that we know what protein is and how digestion works, let’s move to the next step. Let’s look at common feed the ingredients that supply protein in equine diets. Horses get the protein they need from forage and concentrate feeds. A horse’s requirement depends on several factors – such as weight, growth, lactation, gestation, work intensity, etc.
When it comes to forages, the quality of proteins can vary greatly.
As a general rule of thumb, younger plants have a higher protein content than mature plants, which are often also more difficult to digest. For grazing horses, good pasture management, will ensure the horse gets plenty of protein from the grass. In most situations, good pasture will easily meet a horse’s protein requirements when the horse has access to grazing for most of the day.
If we look at hay and haylage, the key factor determining protein content will beare the time of the harvest and the plant species. Generally, the first cutting will have a considerably higher protein content than a late-season cutting. Additionally, legume hays such as alfalfa will be higher in protein that is more digestible than grass hays such as timothy. ,. Although the protein in dried forage is less digestible than grass, good quality hay will cover the protein needs for many horses with exception of those with higher needs (i.e. exercise, broodmares, growing horses).
In addition to the forage, most horses also receive some additional protein through concentrate feeds. Here too, quality takes precedence over quantity. For example, feeding your horse concentrates with only grains will not be enough. The protein quality in grain is simply too low. Protein of the highest quality is found in ingredients like whey protein concentrate and potato protein. These type of ingredients you often find in higher concentrations in supplements or balancer products. When it comes to standard feeds, the most common source of protein in is oilseed meal. This is what remains after the oil is extracted from seed. Examples include soy, rapeseed/canola, and linseed. The most commonly used protein in horse feed is probably soybean meal. This is because soybean meal is widely available and known to be a high-quality protein source that is highly digestible and has an excellent amino acid profile.
We have written several articles on protein and we have compiled them for you!
- Read all about protein quantity and quality here
- Read more about the basic prerequisites for building topline here
- Read all about equine muscle development here
Tips from the Cavalor experts
Now that you’ve read this article, you know lots more about proteins. But which products can help to meet the (increased) protein needs of horses? We’ve put together a list of Cavalor products that are high in quality protein. However, keep in mind that even more important is a complete and balanced ration. Feed as you need!
Cavalor Probreed – a high-protein mix for pregnant and lactating mares and weanlings. This mix supports proper development and balanced growth in foals and keeps mares in good condition. Pregnant and lactating mares have higher protein requirements. From the 7th month onwards, it’s important that the mare’s diet will be supplemented with feed that is high in protein, trace elements and vitamins – these include copper, zinc, manganese, calcium, phosphorus and magnesium. As the foal grows inside her, it takes up more and more space, applying pressure on the organs of the digestive system. Easily digestible proteins are necessary for the foal’s development and for the production of milk.
Cavalor Strucomix Senior – this is a high-fibre, high-structure mix without oats that’s tailored to the nutritional needs of older horses. Its extruded grains and high-quality proteins make it easy to chew and easy to digest. Proteins facilitate weight and muscle maintenance.
Strucomix Senior is high in fibre and contains pro- and prebiotics to support bowel function. That’s ideal for keeping your horse calm and in control. Contains omega 3 & 6 fatty acids, minerals and vitamins to support health and strengthen the immune system.
Cavalor Strucomix Sport – the first muesli with fibre for sport horses in the Cavalor sport feed range. Along with having added fibre, this muesli fully meets extra energy, protein and multivitamin requirements. It also contains pre- and probiotics for the development of good gut flora: the basis for the body’s natural resistance. Its puffed grains ensure good absorption and smooth digestion. Cavalor Strucomix Sport contains essential multivitamins to meet the increased vitamin requirements of sport horses. Cavalor Strucomix Sport is a Level 2 feed for horses that are in regular and active training.
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