2.1. The "Inside" Science of Nutrition

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Del curso dictado por University of Illinois at Urbana-Champaign

Sustainable Food Production Through Livestock Health Management

126 calificaciones

University of Illinois at Urbana-Champaign

Sustainable Food Production Through Livestock Health Management

126 calificaciones

Learn about the impact of infectious disease on sustainable animal-based food production by understanding the science of growth, immunity, and infection and by learning the problem-solving skills needed to advance animal health and food production through optimal management practices. There is a growing global need in agricultural production for a workforce that is capable of integrating knowledge of animal health and production with an understanding of consumer preferences in the context of economic reality, business efficiency, and ethical constraint. However, current evidence suggests that there is a growing shortage of people with the knowledge and problem-solving skills required to match the rapid advances being made in animal health, science, and food production. The results of this shortage are wide-ranging and could lead to challenges in food security and agricultural economic competitiveness in some countries. In this course we will explore the effect of infectious disease on sustainable animal-based food production. The content and learning outcomes of this new course will be designed to be relevant across different food production sectors (i.e., beef, dairy, poultry, and pigs). While the instructors will provide the participants with a strong scientific base for understanding the impact of infectious disease in animal-based food production, the emphasis of the material will be on practical problem-solving and will be directed towards equipping participants with a platform for developing the skills needed to contribute to sustainable food production.

De la lección

Week 2: Disease as a Barrier to Sustainability

This week we will demonstrate the link between nutrition and health at every stage of life and production by examining the science behind efficient nutritional intake, uptake, and utilization, and exploring the mechanisms by which disease can interfere with these processes.

2.1. The "Inside" Science of Nutrition 11:29

2.2. The Particles and Partitioning of Dietary Nutrients 9:11

2.3. Failure of Nutrient Utilization: Characterization and Treatment17:15

2.4. The Two-Way Street of Organ System Health and Nutrition10:09

2.5. Nutrition and Disease: From Tip to Tail7:21

2.6. The Toll of Infectious Disease on Growth and Production8:59

Conoce a los instructores

Dr. Jim Lowe, DVM, MS, Dip ABVP (Food Animal)
Associate Professor
Integrated Food Animal Management Systems, College of Veterinary Medicine
Dr. Brian Aldridge, BVSc, MS, PhD, Dip ACVIM (Large Animal), MRCVS
Clinical Professor
Integrated Food Animal Management Systems, College of Veterinary Medicine

[MUSIC]

In our livestock based food productions, an important element

is how those animals take those plant based components and

convert them into products that we find palatable and digestible?

Taking care of nutritional feeding is so important, because it comprises

such a significant proportion of the cost of our production and

that's true for all of our systems.

But the actual proportion varies depending on the species and

depending on the type of system, and the consideration.

How much nutrition contributes and how much it costs depends on those things.

Dairy cattle, for instance, that are raised somewhat a pasture.

Nutrition might be 50 to 60% of those costs.

Whereas with pigs, it might be 80% of the cost of production in a swine system.

But because of these costs optimizing the nutritional content and

matching it with the production outcomes is a essential part of the management of

running of an efficient, effective and profitable system.

Because the costs are such a high proportion of the total costs that

go into an animal and nutrition, feeding an animal isn't just simply

turning them out onto a pasture or putting feed in front of them.

Nutrition is a complex, scientific process.

Feeding the animals exactly the right constituents at exactly the right time is

really important for the sustainability of production.

And to understand nutrition to be able to design good nutritional programs,

you need to be able to understand not just the components of the nutrition,

not just what the components of plants are and how they're made up,

but also the anatomy and physiology of the animal.

How their intestinal tract works?

How they digest nutrients?

How they maximize those to become most efficient in production?

So I'm Dr. Brian Aldridge,

I'm here at the College of Veterinary Medicine at the University of Illinois.

We're in the Department of Anatomy and to start to understand that science of

how nutrition works, we're going to go inside of a cow.

This is a skeleton of an adult cow that's used here as an anatomy demonstration to

teach the veterinary students.

The structures that are inherent to the function of this animal and

we want to just show you where the major part of the digestive system sits.

For ruminants, they're unique,

because they have four compartments to their stomach.

And within their abdomen, they have a massive fermentation vat called the rumen.

That's the second of the stomachs and it sits right here within

the belly of the animal, and all of the other structures

are secondary to really this rumen in the digestive process.

The rumen lining has small little papillae.

Little leaves, tiny little microscopic leaves,

which increase the surface area of the rumen.

And therefore, optimize its absorptive capacity.

Absorbing the breakdown products of the bacterial fermentation, particularly

the breakdown products of carbohydrate metabolism, the volatile fatty acids.

And that is the seat of efficiency for nutrition and the seat of efficiency for

production, as far as nutrition is concerned.

So here I am, holding the four stomachs of a ruminant inside the abdomen of this cow.

So, that's exactly where it sits.

But if you think this is the real structure and this is the real size,

I'm fooling you, because this is actually a sheep's stomach.

And it's about a tenth of the size of that,

which would sit inside this cow's abdomen.

Now, this is the real rumen of this animal.

And as you can see, it's massive.

It's a massive fermentation vat.

Probably all together, this structure holds

something like 300 liters of fluid.

Each compartment structurally designed both in its form and

its function to most efficiently, take indigestible proteins and

carbohydrates and make them digestible.

Firstly, for the animal and then to convert them into metabolic products.

So, let me talk you around the different stomachs in this specimen.

The ruminant is unique in that it has four stomachs.

This here is the first stomach, it's called the reticulum.

The reticulum is in some ways, the first compartment that the food meets.

The food comes down the esophagus, down the throat and

through a small sphincter here and is then dumped into this part of the stomach.

It's lined with a reticulated mucosa, which is designed to capture particles and

it's so effective that if the animal swallows a piece of wire.

To prevent the wire from accessing lower parts of the intestine,

they get trapped there.

Stones will get trapped in this honeycomb appearance,

stopping its interference with other digestive processes.

And every part of this remarkable stomach system is unique in structure,

but also in lining.

And also, in its contents.

Each of them though, contiguous perform a different function,

because of their anatomical structure.

But this is also the part of the stomach when the food is chewed again and

again, this is the food that goes back up into the mouth.

So, a ruminant doesn't just chew its food once.

It takes in the food, it goes down into the reticular rumen and

then it's brought back up and down, so

that this plant material is in a stepwise fashion crushed and broken up.

And this occurs by a repeated process of chewing of swallowing,

of entry into the rumen vat and then of bringing it back up.

So, this is where rumination takes place.

This is also the first sac of this fermentation vat and food moves from this

structure into this large multi-sacked parts of the stomach called the rumen.

This is where all the fermentation takes place.

Again, it has a unique structure of sacks,

because that's where most of the mixing takes place.

It is mixed up, so that the bacteria are exposed to every part of

that digester and there's three layers of food in this rumen.

There's the top layer which is the gas, which is a byproduct of digestion.

There's a fiber layer that sits in there and that's the part of the fiber that goes

into the reticulum and is rechewed, it's the long fiber.

And then at the bottom, there's food particles suspended in liquid.

Looks more like pea soup.

And that's where the bacteria are doing most of their work being exposed to

the small fibers and doing the digestion,

taking the plant proteins and the complex carbohydrates and

breaking them down into simpler proteins and simpler sugars as well.

Probably, about 1.5 billion bacteria live in that in the animal.

From there, as the food is broken down, the more liquid component goes

through another sphincter, another opening into this omasum.

And every stage of digestion,

the particles are going from long fibers to smaller fibers.

And when it gets to there,

it's essentially smaller particles with a large amount of fluid.

But to get down into the smaller parts of the intestine in the lower parts of

the intestinal tract, most of the water should be removed and

that's what takes place in this omasum.

The lining of the omasum is like book leaves and

it's a perfect way to increase a surface areas such as, so that water

absorption could be maximized and that's where a lot of the water is absorbed.

From there, the food goes into what is really the true stomach, the abomasum.

The stomach that in humans and in pigs, and in horses does most of

the digestive processes of the gastric part of the intestine.

It's the true stomach, because that's where some of the enzymes

are produced that digest some of the carbohydrates and the proteins.

The lining of the abomasum is glandular.

It's full of folds, but it's secretory.

The only part of these four stomachs that secretes anything.

It secretes the digestive enzymes.

It secretes the hydrochloric acid to lower the pH.

It's a true stomach, because it's acidity,

it's pH is much lower than the rest of the intestinal tract.

The secretion that comes out of the lining of this is hydrochloric acid,

as with humans and as with other monogastrics.

So, the components of this part of the digestive tract have been

simplified from the long fiber that we've seen in the rumen and

the bacteria in the rumen have done most of the digestion.

They've been breaking down the celluloses and the starches to more simple sugars.

They've been taking the protein in those plants and

breaking them down into their essential acids.

In fact, the bacteria then take the amino acids and

put them into the protein of their own body wall and

they form part of the nutrients for the lower digestive tract.

The abomasum's role and the lower intestine is to take those bacteria,

and break them down, and to release the nutrients that they have released

from the grasses, and the grains that took place during the fermentation process.

So in some way for the ruminant,

the bacteria become an important dietary component.

The bacteria break down the plants and then the rest of the body digests

the bacteria, but there's things that we do nutritionally and managementally,

which affects the structure and function, the contents of these rumen.

If we don't get the nutrition right,

then we mess up the function of this wonderful organ.

And therefore, we decrease productivity.

[MUSIC]

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