Microbes Help Predict More Efficient Cattle

The number of people in the world is rapidly growing and with more people comes the need for more food. Luckily, cattle are a great resource to help provide more food! These animals can produce more protein than they consume, converting human-inedible grasses into high-quality protein for humans to eat. However, we can still improve this conversion of grasses to meat by making cattle more efficient at the process, otherwise known as making cattle more feed efficient. In this study, we identified stomach microbes and blood nutrients of feed-efficient cattle. Using computers, we were able to show that the nutrients in the blood could predict the microbes living in the stomachs of feed-efficient cattle. This work shows that microbes in the stomachs of cattle may help improve feed efficiency and can be used to predict which cattle are feed efficient.

a rumen, and this is where most of the plants that ruminants eat get broken down. The rumen of cattle can hold almost gallons of food and water-that is a lot of food! The ruminants are able to break down plants that humans cannot eat because of the tiny microbes that live in MICROBES Microscopic organisms that live all around us. Microbes include bacteria, fungi, and protozoa. the rumen. The microbes have special proteins, called enzymes, that can attack and digest the tough materials of the plant. Humans do not have the same enzymes that these microbes do, so ruminants can use plants and other foods that humans cannot use.
Since the microbes are the ones mostly breaking down the food that cows and other ruminants eat, they make a huge di erence in how well the cows can use di erent kinds of feed to gain weight. Some cows and microbes are really good at breaking down the food and using the energy and other nutrients that come from it, and some are not so good at it. Cows that are good at breaking down food to get energy are called feed e cient. Feed-ine cient cows are not as good at extracting energy from food.

COMPARING MICROBES AND NUTRIENTS IN DIFFERENT TYPES OF CATTLE
Some of our recent research uses a combination of lab techniques and computer analyses to try to find a quick, easy, and cheap way of figuring out which cows are feed e cient, and how the rumen microbes may be helping them be better at using their food. First, we take blood samples from the cows. Then we collect the microbes in the rumen by placing a tube down the throat to the cow's stomach and pumping some of the stomach contents out. In the lab, we then break open the microbial cells to get the DNA from them, which allows us DNA The material, present in nearly all living things, that is the carrier of genetic information.
to identify which microbes are present. We also measure the amounts of di erent nutrients in the blood of cows that are able to gain more weight with less feed and those that do not gain as much weight with the same amount of food. After we find out which microbes are living in the gut of the cattle and the amounts of nutrients in the blood of the di erent animals, we analyze how these factors are di erent between feed-e cient cows and feed-ine cient cows. Finally, we use computers to calculate the relationships between the microbes and the nutrients, which allows us to see how the rumen microbes may be helping the cows be better at using the food we give them ( Figure ).

WHAT DID WE FIND OUT?
First, we looked at the microbes in feed-e cient and feed-ine cient cattle [ ]. Since there are hundreds of di erent kinds of microbes that live in the rumen, we wanted to see if the feed-e cient and feed-ine cient cows had di erent kinds of microbes living in their rumen. We did not see any di erences in the number of kids.frontiersin.org September | Volume | Article |

Figure Figure
Finding ways to identify feed-e cient cattle through microbes. When cows eat grass, the grass feeds the microbes, which in turn feed the cow. Researchers can examine the microbes in the rumen and the nutrients in the blood of cattle to see whether feed-e cient cattle have di erent microbes or nutrients than feed-ine cient cattle do.
di erent kinds of microbes or any changes in how related the microbes were between the feed-e cient and the feed-ine cient cows. However, we did see di erences in the numbers of specific microbes between the two groups of cattle. For example, the bacteria group of Flavobacteriia were greater in feed-e cient cows. We also observed that three di erent kinds of microbes seemed to be the ones responsible for causing the variation in the ability to use nutrients.

MICROBES MAKE A DIFFERENCE!
But even if there are di erent microbes, are they really making a di erence in what nutrients the cows are getting? To answer this question, we looked at the nutrients found in the blood of the cows. First, we found that the feed-e cient and feed-ine cient cows had di erent amounts of certain nutrients [ ]. One of those nutrients, called pantothenate , was greater in feed-e cient cows.

PANTOTHENATE
Commonly known as Vitamin B , and is important for the breakdown of the foods we eat into substances the body can use.
Pantothenate is used to make a special molecule called coenzyme A (CoA). Coenzyme A is really important for many animals because COENZYME A (CoA) An abundant and essential molecule that is involved in a lot of energy-related processes.
it is involved in turning food into energy and in building muscle [ ]. However, animals do not have the tools to turn pantothenate into CoA, but certain microbes do.
Knowing this, we wanted to see if there were any microbes from the rumen that could turn pantothenate into coenzyme A. We found that one group of bacteria, called Flavobacteriia, was greater in number in the rumen of feed-e cient cows. We then used computers that could perform very complex math to determine the relationship between the pantothenate and the Flavobacteriia. We found that the amount of pantothenate in the blood of cows could "predict" the amount of Flavobacteriia that was living in the rumen. So, the lower the amount of pantothenate in the blood, the lower the amount of Flavobacteriia living in the rumen of the cows. As the amount of pantothenate in the blood gets higher, the more Flavobacteriia are found living in the rumen. This is really important for a couple of reasons. First, both pantothenate and Flavobacteriia are more abundant in feed-e cient cows. This might mean that both pantothenate and Flavobacteriia can be used by scientists and farmers to decide which cows are going to be better at using their food. Choosing and growing cows that are better at using their food means that the cows can grow faster and use less food, which is better for the environment [ ]. Our findings also mean that the microbes in the rumen do change how the cows use the nutrients in food and the nutrients produced by microbes. Sometimes the small di erences that scientists find between two groups of organisms do not actually a ect the organisms. But our work provides more evidence that the di erences in the rumen microbes can a ect how the cows' bodies work to extract energy from food [ ].

HOW ARE WE GOING TO USE THIS INFORMATION IN THE FUTURE?
We are hoping to be able to use this information in several ways. First, we hope to eventually develop a test that can use a little bit of blood to measure how e cient cows are at using the nutrients from their feed. Pantothenate may be one of those nutrients that can be used to measure feed e ciency, but we would also like to find others.

FEED EFFICIENCY
A simple measure to determine the ability of cows to turn their feed into milk, milk components, or body weight.
We also hope to find more microbes that are changing or producing the nutrients that make ruminants better at using their food. If we know which microbes are making the nutrients that are helping the ruminants use their food e ciently, we may be able to feed more of those microbes to the ruminants to help them use their food even more e ciently. There is still a lot of work to do before we get to that point, but the work is very important because happy, healthy cows are better for people and better for the environment. . doi: . /frym. .

CONFLICT OF INTEREST:
The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
COPYRIGHT © Clemmons and Myer. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

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Hi, I am Megan, my hobbies include musical theater, baking, and surfing (only during summer though!). I got involved with Frontiers for Young Minds as I really want to learn more about science and the world around me, I through reading these articles would be a good start! AUTHORS BROOKE A. CLEMMONS Brooke A. Clemmons is a Ph.D. student in Animal Science in Knoxville, TN. She grew up in cities, but always loved farm animals. Brooke currently works with cows to understand how di erent environmental things a ect how cows use food. She specifically focuses on how di erent factors like pregnancy and genetics a ect the microbes that live in the guts of cows, and how we can use those factors to make animals grow better and healthier.
PHILLIP R. MYER Phillip R. Myer is an Assistant Professor at the University of Tennessee Department of Animal Science. He is interested in how microbes in beef cattle impact feed e ciency. Phillip is also interested in how beef cattle can interact with their microbes. His research group uses DNA technologies to help investigate these interactions. He hopes his research can help inform, improve, and be part of the solution to future global protein and food demand. *pmyer@utk.edu