3.8. The War Within

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From the course by University of Illinois at Urbana-Champaign

Sustainable Food Production Through Livestock Health Management

90 оценки

University of Illinois at Urbana-Champaign

Sustainable Food Production Through Livestock Health Management

90 оценки

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.

From the lesson

Week 3: Animals' Response to Infectious Disease

This week we will introduce the concept of the farm and each production system as an ecosystem in which animals and microbes live in mutualistic relationships, and explain the beneficial impact of ecologically managing the microbes alongside the animals to enhance host defense, animal health, and production efficiency.

3.1. Microbes: Friend or Foe? 10:21

3.2. Promoting Friendly Farm Infections 7:46

3.3. Microbial Colonization in the Newborn World 8:35

3.4. The Farm: It’s a Bug’s World 8:51

3.5. In Defense of Normality 12:11

3.6. The Energetic Cost of Defense 7:37

3.7. When the Defense Cannot Defend 14:22

3.8. The War Within 7:27

3.9. Defending the Airways 7:51

3.10. Defending the Next Generation 8:45

Meet the Instructors

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

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[MUSIC]

I'm Dr. Brian Aldridge and I am here in the imaging unit at the large animal

hospital at the College of Veterinary Medicine at the University of Illinois.

I'm standing here to illustrate some of the more sensitive

detection mechanisms that we have.

How do we detect disease?

How do we look inside of the animal and know the disease is taking place?

We see about 1,000 food animals that come to the hospital each year.

And you might wonder why on Earth do we see that many animals.

Why do animals come to the hospital?

Well, we think of them as iceberg indicators,

that's what we call them, iceberg indicators.

Because they're often the tip of the iceberg.

What you can see when you can see obvious disease,

they're really the most severely affected animal in the whole spectrum of disease.

You see disease comes in many different forms, many different severities.

So it can affect different body systems.

It can be caused by different agents, but also be in different degrees of severity.

So when we have an animal that comes to the hospital,

the owners notice that something is wrong with that animal.

It might be that it has a cough, has a nasal discharge,

has some problem with intestinal function, has diarrhea,

it might be losing weight, or it might be, or it might be lame.

We often then embark on a set of investigations to work at what's going

on with the animal so we can direct therapeutics and treatment and

give the owner an outlook as to whether that animal will recover and

what will the cost be in treatment of that animal.

But we also take care to point out to the owners that this animal is often

an indicator of something that's taking place back in the herd,

in the population, in the flock.

Every animal that you see sick, for

every animal that you see sick ihere's usually three to seven or

eight more animals that have the same disease but to lesser degrees.

That's not true, obviously, if you have an animal that has a fracture or

something that's traumatic.

But that's particularly true with infectious disease.

Why would one animal become ill and none of the others be infected?

If that animal is the index case, if that animal is the first one,

then it's possible that the other animals in the herd have contracted that disease.

Or maybe there's something about that animal's immune system, or genetic makeup

so it's more susceptible, and the others are not exhibiting the same signs.

So the process of unraveling that disease is really important in showing you,

and showing the producer, what else is taking place in

the herd because infectious disease impairs productivity.

Think about respiratory disease, for instance,

when you have an outbreak of respiratory disease in a population, the ones that

are most susceptible will present with fevers and they might go off their feed.

But some of those will recover spontaneously, and

show no other signs, some of them will continue in that phase of the infection.

But some will progress to a certain type of disease,

in which the the infection becomes established within the lungs.

And, therefore, the outward signs might not be very evident.

So that's when we can use other diagnostics,

other signs that the disease has been taking place inside of the animal.

And very often what the clinical signs to the producer would be is,

a change in productivity, a change in weight gain, a change in milk production,

a change in growth characteristics.

So very often it might not be a cough or it might not be diarrhea,

it might not be an overt weight loss, it might be a subtle change.

But unless we're measuring those things we won't be able to detect it.

An animal with intestinal disease as well, the intestine needs to be

fully functioning to absorb all of the nutrients.

And if there's any impediment for

that then essentially all the nutrients that are taken in and all the costs that

are being put into that animal, they're going into the disease process itself.

Some of those nutrients might not be absorbed and

are being passed just out in the feces.

So, essentially, the owner's wasting money.

It's an area of inefficiency.

It's also an area of inefficiency because those nutrients aren't being

used to growth.

So if in the production system the owner has certain targets, and

if the target is a kilo or two kilos of growth, and let's say the animal is

growing at half a kilo because it can't absorb all of those nutrients.

Then that disease is causing an inefficiency,

even their might not be any overt clinical disease.

An animal with lameness, the energy that go into the pain response for that animal,

pain invokes a whole set of physiological responses that takes energy and

takes protein and takes nutrients away from the growth process or

away from the production process.

So we know, too, with the immune system that a low grade infection,

a chronic infection, one that's been there a long period of time but

doesn't show overt clinical signs, can redirect nutrients away from growth and

productivity to the immune system so that growth becomes inefficient.

The food conversion efficiency is reduced.

Every kilo or pound of food isn't being converted into the amount of

growth that it should do, because those nutrients are being diverted away.

That's why disease can affect production efficiency, and we need to have

good monitoring systems by which that low level of disease can be detected.

Disease detection isn't just picking up the sick animals.

The ones that have those overt clinical signs.

It's also monitoring productivity.

So we can do that by looking at production records.

We can make sure that animals are identified

early in the process of the disease.

Because the longer a disease Is present in a host body,

the harder it is to treat, and the harder it is to reverse.

So the acute short-term diseases are much less severe in production

reduction than are the low grade, long-standing chronic infections.

So in your management systems think about ways in which your monitoring for disease.

Certainly we need to pick up those animals that serve a source of infection.

Certainly we need to pick up those animals that are suffering.

But you need monitoring systems by which you can pick up disease that's low grade

and hidden from the visible eye.

And pick them up early so that you can intervene and treat those disease, or

put in place preventative strategies so

that it doesn't spread and effect the rest of the herd.

[MUSIC]

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