5.3. Stress Biology: Caring for the Inside First

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From the course by University of Illinois at Urbana-Champaign

Sustainable Food Production Through Livestock Health Management

116 ratings

University of Illinois at Urbana-Champaign

Sustainable Food Production Through Livestock Health Management

116 ratings

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 5: Our Role in Preventing Infectious Disease

This week we will be discussing the role of caregivers in managing, preventing, and controlling infectious disease in livestock-based production systems, and help you appreciate how an understanding of the prey-predator relationship can be used in the design of management strategies to offset physical, physiological, and psychological stress.

5.1. Building Defense by Building a Fence 9:31

5.2. Maximizing Defense by Customizing the Fence 8:34

5.3. Stress Biology: Caring for the Inside First 10:45

5.4. Behavior: The Window to Stress 6:18

5.5. Predators and Prey: The Origins of Stress 3:42

5.6. Thoughtful Management: The Foundation of Well-Being 5:42

5.7. Changing Stress: Movement and Thermal18:48

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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I'm Dr. Brian Aldridge from the University of Illinois, College Veterinary Medicine.

And as we think about livestock production,

one important element is the use of animals for production.

That's right, in the world there's a big debate about whether that's right or

not, should we use animals in our production systems?

It's interesting when you think it.

The farmer, or the producer in many ways cares about the animal

more than anybody else on the planet.

All of the systems of management are set up for animal well being.

Because an animal that's not looked after well will not be productive.

So when you talk to farmers and

producers they really care about the well being of their animals.

They are the biggest welfare advocates that you can see.

There are three areas of well being which a producer, a farmer takes care of.

And just as anybody would take care of their dog, or their cat, or

their pet animal, the farm has the same concerns.

They would take care of their physical well being, they take care of their

physiological well being, and they take care of their psychological well being.

If any of those things are disturbed then the animal is set off kilter.

Its ability to maintain normality and therefore, to be productive and

to be profitable for the producer is inhibited or impaired.

So a lot of our management is designed around the idea of well-being,

of optimizing animal well-being.

And of course the idea is if you optimize well-being,

you will optimize production profitability and production efficiency.

But there's nothing wrong with that, all that does is,

ensures that the animal is well looked after.

So in this lecture we want to talk a little bit about

when well being goes wrong and the term we use is stress.

Stress is when an animal is taken out of it's comfort zone as it were.

And people talk about five broad freedoms.

These are elements in which we can measure, elements in which we can

look at to see how well being is being disturbed, and is the animal stressed.

They are the freedom from hunger and thirst, the freedom from pain,

the freedom from discomfort, the freedom from fear, and

the last one is the freedom to express normal behavior.

So when we design management systems,

we take all of those into consideration to optimize animal wellbeing.

So we make sure that they are fed in such a way,

that they are free from hunger and they're free from thirst.

The kinds of food that they get and the access to that food

ensures that they always have food available.

And it's the best food designed for their stage of production, their stage of life.

The second thing is we design shelter.

We design housing to protect them from physical discomfort.

So we'll look at that a little bit later in this lecture.

But we design it specifically so that they're protected from the elements,

protected from predators, and

they can actually exhibit normal behavior in those housing situations as well.

So what we're able to do is, we need to, as biologists and scientists,

we need to understand a little bit about stress,

about how the animal maintains normality and that process is called homeostasis.

And what are the kind of things that can upset that balance?

And what we need to do to understand that is we need to look at

the neuroendocrinological system of the animal.

So when we come to trying to understand the biology of stress,

we have to understand what's taking place inside the body.

The animal has certain physiological and psychological and physical needs.

What we do managementally can impact them positively or impact them negatively.

So an animal responds to its environment, and it does that by all of its senses.

So an animal will have auditory inputs, visual inputs, olfactory inputs.

And those are all detected at a part of the brain called the hypothalamus.

And that's a scent in the center of the brain.

And it's where really the processing for

all of the physiological mechanisms are programmed and coordinated.

So, if an animal sees a predator, for

instance, that would be detected visually or by the nose, and

on olfactory stimulus, and that would be transmitted to the hypothalamus.

And the hypothalamus then conducts that message

to an endocrinological gland called the pituitary.

And it does that in a remarkable way.

It secretes some hormones and

the hormones are chemicals which have an affect at a specific site in the body.

And these hormones can, a rat can travel around the body in the bloodstream but

from the hypothalamus, they reach the pituitary in a very controlled way.

They go down two nerve pathways.

They're nerve hormones or it's a neuroendocrinological pathway.

The pituitary is a key gland in determining

physiological responses in the whole of the body.

So there's several parts of it.

There's the anterior pituitary, the posterior pituitary,

and there's an intermediate part of that, called the pars intermedia.

And depending on the input from the hypothalamus,

different hormones are secreted.

The main ones we're interested in with in terms to stress,

in terms of maintaining normality or homeostasis are the hormones that

leave the pituitary gland via the circulation, they reach the adrenal gland.

The adrenal gland is a small glad that sits near the kidney.

And the main hormones that affect that are called ACTH or

the Adrenocorticotropic Hormone.

So the environment, physical stresses,

chemical stresses, management stresses are detected by the animal they

programmed in the hypothalamus they're transmitted to the pituitary hormones and

then released, which have their impact at different parts of their body,

the main one of which is the adrenal gland.

And the adrenal gland has two main parts, it has a medulla and a cortex.

And one of the major hormones that is Protective for the animal but

if it gets out of balance can have negative effects, it's called cortisol.

And cortisol is produced in response to this hormone from the pituitary

called ACTH.

And cortisol has widespread effects, usually they're good,

they're physiological but in an extreme they can become,

they can have a negative or a deleterious effect as well.

So cortisol can effect a metabolism, a carbohydrate metabolism so

how sugars are dealt with in the body.

It can effect fat metabolism, how fat is dealt with in the body.

And it can also importantly effect the immune system.

So when the stresses are too great and the secretion of cortisol is too high,

then we can actually have immunological effects of that.

In our production system, our intent is to design a system in which

the stress is minimized and the homeostasis or normality is optimized so

that there's not too much secretion of hormones like cortisol.

Another set of hormones released by the adrenal are called the catecholamines.

These are familiar to many of you.

They're named adrenaline or noradrenaline.

Some people call them epinephrine or norepinephrine.

And when they're released from the adrenal, these have different effects.

They don't so much effect the metabolism, but they effect some of the fight and

flight responses, such as heart rate and circulation and respiratory rate.

And these are protective responses, so when a stressor, an animal is

exposed to a stressor the body needs to respond in an appropriate way.

We'll see that when we see prey predator reactions, when a predator appears,

the prey needs to respond, increase bloodflow to the muscles,

increase its heart rate in a way to escape from that predator.

But some of our physical, psychological, physiological stresses can also lead to

an increase in secretion of adrenaline, noradrenaline and of cortisol.

And when they do that they can have negative effects on metabolism,

negative effects on behavior, and negative effects on the immune system.

So what we do when we optimize our management systems in livestock

production, is we do it that in such a way

that that pathway is maintained within physiological limitations.

There's not too much, in an optimal system there's not too much hypothalamic,

pituitary and adrenal stimulation.

So there's not too much cortisol and

some minimal immune suppression a minimum metabolic disturbances.

There's not too much cortical means so there's not too much cardiac or

respiritually stimulation.

And how do we detect all those things?

Well, we're going to see when we see prey and predator.

The best way to detect that is by behavioral responses of the animal.

The behavior animal is a reflection of its response to these potential stresses.

So an important part of management is detection of stress.

Detection of how the animal is behaving in its environment.

Is the environment, is the nutrition, is the management and the handling of that

animal designed and delivered in such a way that that animal is stress-free.

That's a really important part of our livestock system.

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