July 2018
Feeding Facts

The Root of All Things Feed, Part 1: Protein

We have covered a great deal of things from feed tags and heat stress to haymaking decisions and why they matter. But, really, we have not talked about the root of all things feed-related – the actual nutrients themselves. There are six major categories of nutrients: water, carbohydrates, fats, proteins, vitamins and minerals. I think a good explanation of what they all do and why each one is important in its own way will help you make better feed-buying decisions and, hopefully, put more dollars on your bottom line.

While I could skim over the very basics of each nutrient in one article, I feel that dedicating one article to each one will be better and actually give you enough information to be useful. With that said, the most-often talked about nutrient is protein. More feed is sold based on protein content than any other thing, and we might as well start with it.

Proteins are the main components of our organs and the soft structures of the body. They form the muscles, the tissue around those muscles and everything holding it all in place, including skin and hair or wool (if you’re a sheep). They are the primary constituents in fingernails, hooves and horns.

They also play a major role in our metabolism. They are key components in enzymes that make digestion work. They are vital to hormone production and actions, and immune responses when we are sick.

I could go on and on, but I think it’s already clear that proteins are an important part of any animal’s diet.

Proteins can be deficient in a diet, but they are not normally so deficient that we see catastrophic things such as anemia and death. However, small deficiencies are noticeable. With small deficiencies, you will see a slower growth rate, lower milk production and less efficiency on many fronts from digestion to fertility.

When we talk about proteins in feed, or at least on the feed tag, we are talking about crude protein. While that is an important number, it only tells a small part of the whole story. Crude protein can be divided into two parts: true protein and other nitrogen containing products called nonprotein nitrogen that cattle, sheep and goats can generally convert to true protein. Swine, equines and poultry normally can’t use the NPN. While it is not helpful, it generally isn’t harmful in low levels.

True protein is the main focus and what the animal digests. True protein is composed of a mixture of 22 amino acids. Without diving too deeply into chemistry, amino acids are different configurations of carbon, hydrogen and oxygen with nitrogen and an occasional piece of sulfur thrown in for good measure. If you think about amino acids like Lego blocks, they are one or two or 10 blue blocks (carbon, hydrogen, oxygen) together and one red block (nitrogen) stuck on the end. To oversimplify, the main difference is how many blue blocks there are for each red one and how each is shaped.

The main thing you need to know about amino acids is that there are differences and each animal needs a different mixture to grow and perform at its best.

Ruminants can take a poor mixture and let the microbes in their rumen work their magic and produce the correct mixture. Swine and poultry cannot, and it is essential the correct mixture is provided. Any good swine or poultry feed will have that worked out before you buy it, but that is one reason why you won’t get maximum growth by feeding swine feed to a chicken or chicken feed to a pig. Horses also need the right mix, but, with their digestive tract, they are more forgiving than the pig or chicken.

At any rate, if an animal is deficient in any one of the amino acids, the others won’t work properly and their performance will slow down to the level allowed by the deficient amino acid.

What is the takeaway and how does that help you buy feed?

Keep some things in mind while you are looking at feeding options.

First, balance is important. Too much protein can be as bad as not enough. Most likely, because protein is one of the more expensive nutrients, we won’t often overfeed it.

Second, the percentage listed on the bag is important, but not nearly as important as you would think. All animals have a protein requirement, and it is usually expressed in pounds or grams per day. For instance, if a cow needs a pound of protein (I use a pound just because the math is easier) and you feed a 10-percent protein feed, the cow will need 10 pounds of feed. If you feed a 20 percent protein, that same cow would only need 5 pounds.

Both will work and the only relevance the percent protein has is in determining how much you need to feed. Generally, the higher the protein percentage, the less you have to feed.

Third, keep in mind that younger and smaller animals tend to eat less and will require a higher percentage to meet their needs with the amount they can eat in a day.

Protein is important and often misunderstood. As we continue down this path in the coming months, I hope it will all tie in and make more sense; which, in turn, will allow each of you to make good decisions regarding feed needs.

If you have any questions about what your animal will need, feel free to call or send me an email.


Jimmy Parker is AFC’s animal nutritionist.