ADP20306 Summary Thermoregulation (2023) (21.6h planned)
Disclaimer: times are based on how long it was scheduled on campus, looking at the material for the first time will
take around the same hours, studying the summary itself will take less. This is a thorough summary, including
lectures and practicals, but not the book, for thermoregulation is a summary of the reader included
QUIZLET Thermoregulation
Find Latin word origin for when knowing difficult latin words etc.: google: (word) + etymology
YuJa classes: https://wur.yuja.com/P/VideoManagement/MediaLibrary/MediaChannel/43464
Thermoregulation
Reader is the exam; lectures are based on part of the reader. Tip: lectures is good for understanding it all, reader
questions are the main focus that look like the exam questions, also keep drawing schemes and graphs to illustrate
for yourself, it helps with understanding
6 open questions; 1/3 knowledge, 1/3 insight, 1/3 calculations (8 sub-questions)
Lectures (8x 12h) & Reader summary
L1: Introduction to thermoregulation and heat loss: Chapter 1, 2 HvdB – Oct 31 (1.5h)
Requirements: PP series: thermo lecture 1.
Thermoregulation, chapter 1, 2
L1 part 1: Chapter 1 + Learning goals
• How energy from food is used and how heat production has a place in it (Ch1)
Chapter 1
Main reason of housing animals
▪ Control of:
● growth and/or production: Training schemes of horses is also production, can be detrimental for
health and welfare
● Reproduction: insemination
● health and diseases: Oostvaardersplassen
▪ Manipulation of:
● Behaviour: placing laying nests instead of having to search all over the yard for eggs
● Feed: give right nutrients (pets also)
● reproduction
● Longevity: paralyzed animals, manipulate legs with equipment
▪ Conditioning of:
● Climate: right ventilation, oxygen etc
● health and diseases: vaccines and medicines
Housing
▪ Often developed for economic reasons: livestock, zoos, pet shelters
● increasing production
● decreasing costs
▪ Assessed for social implications
● consequences for animals
▪ Welfare, consequences for humans like fine dust
▪ Ethical discussions
● consequences for humans
● impact on the environment
● consequences for third parties: neighbours
In Artis old part: cages 1 to 1, show as much animals as possible
Now: more animals in a more natural environments
Fluctuation of housing:
First normal to keep animals outside, 20 years later for hygienic reasons inside, then indoors then again outdoors for
welfare reasons, or even mud pool (organic)
50 years ago, teacher in picture: 10 sows, that’s all
,-->Thus, housing is not constant, depends on social, etc
We have the idea that it is better for animal health, welfare or production
How can we measure if the current housing system is proper enough?
Measuring housing effects
▪ Hormonal levels: stress hormones, cortisol, adrenaline
▪ Fertility: oestrus expression
▪ Health and disease resistance
▪ Behaviour: prevalence of different diseases
Thermo:
▪ Production: meat, eggs, wool
▪ Growth: meat
▪ Heat production and heat loss
Thermoregulation: housing
Why are you and I producing heat?/ Why do we lose
heat?
An animal in all cases, you want to maintain your
homeostasis, your internal environment
→ What’s happening: Environmental change
(temperature), Environmental interface (skin),
disruption of body equilibrium (sensor in your
skin sensing and sending a signal to CVS) -->
can do 2 things :
→ behaviour, when that does not work:
metabolic response: increase activity
(heat production)
→ Then regain body equilibrium (not cold anymore)
→ When it is occurring more often, then at a certain moment you are adapted: everyday heater colder,
then experience cold not so bad anymore
Shivering is autonomous response
Behaviour: making body as small as possible, jumping (like sheep go together to stay warm)
Environmental change costs energy, where does it come from? --> food, body energy storage
Spend energy on other things:
Energy reallocation to maintain homeostasis.
Where does that energy originate from?
Food intake (most important)– excreta (faeces, urine)-
available nutrients used for M or P.
Maintenance is maintaining homeostasis, main processes,
heartbeat, immunology
Production, meat etc. sport is production and workload
,Feed intake is gross energy (GE), part of it not digested (faecal energy (FE), (faeces)), then what's left is digestible
energy (DE) not all is utilized, part of it is excreted in the urine (UE) then what’s left is metabolizable energy (ME) =
available nutrients
Gross energy – faecal energy and – urinal energy = metabolizable energy (available nutrients)
Metabolizable energy used for 2 purposes:
- Maintenance (MEm)
- Production (MEp)
What is happening with the energy for maintenance?
When you don’t produce, all the maintenance energy ends up in heat (M)
Where does the energy for production end?
When you are producing, end in
Retained energy (RE) / Net Energy (NE) / Energy Balance (EB)
Is the conversion of MEp to EB with an efficiency of 100%?
Not 100% efficient
Efficiency is partial efficiency (k) (around 70%)
Where does this energy go?
A part is moved to heat other part EB (products)
Heat = 1 – k
How large is M (heat production)? (3rd lecture)
M = MEm + (1 - k) * (Mep)
M = MEm + (1 - k) * (ME-MEm)
--> Only holds in the thermal neutral zone (TNZ)!!!
& All energy for MEm ends up in heat
What is your EB?
What is the energy balance of an adult human who is not pregnant or lactating? under normal conditions
(temperature, etc.)
Your MEp=0, all went to M, EB = 0
Growing, lactating exercising animal: EB = positive +
Losing weight: EB = negative –
Chapter 1 Introduction Thermoregulation (Summary)
Animals were and are housed for several reasons:
1. Control of 2. Manipulation of: 3. Conditioning of:
a. Growth and growth efficiency a. Behaviour a. Climate
(especially meat production) b. Food b. Health and diseases
b. Production (e.g. milk, eggs, wool) (qualitatively + quantitatively)
c. Reproduction c. Reproduction
d. Health and diseases d. Lifespan
Animal housing aspects:
- Positive: supply of food and water and shelter against extreme climatic conditions;
- Negative: needs of animals are not (completely) met.
, To measure performance, health and welfare of animals’ different characteristics can be determined, such as
changes in: Behaviour, Hormone levels, Fertility, Health
and disease resistance, Production, Growth, Heat
production/dissipation.
Homeostasis
The animal body’s attempt to maintain a constant and
balanced internal environment. When the same stressor
persists for a long period of time or reoccurs often, an
animal will adapt to it and the specific stressor will no
longer be perceived as such.
Three different concepts distinguished related to
adaptation to stressors:
• Acclimation: All reactions of an animal occurring after changing 1 specific environmental factor. E.g., a chicken
will acclimate to change in day length.
• Acclimatization: All reactions of an animal occurring after more complex changes in climate and/or housing
conditions. The responses can be caused by several factors at the same time. For example, a dairy cow with
outdoor access will acclimatize to weather changes, such as sun, wind, temperature, and day length.
• Habituation: Adaptation to a repeated stimulus that is initially experienced as a stressor.
Reallocation of energy
Reallocation of energy. *k = partial efficiency (the rate at which ME is converted into NE).
Adaptation of an animal to a stressor has not only consequences for digestion and energy metabolism, but also for
the energy distribution within the animal.
1. Give a definition of acclimation, acclimatization and habituation. (EXAMT)
• Acclimation: All reactions of an animal occurring after changing 1 specific environmental factor. E.g., a chicken
will acclimate to change in day length.
• Acclimatization: All reactions of an animal occurring after more complex changes in climate and/or housing
conditions. The responses can be caused by several factors at the same time. For example, a dairy cow with
outdoor access will acclimatize to weather changes, such as sun, wind, temperature, and day length.
• Habituation: Adaptation to a repeated stimulus that is initially experienced as a stressor.
2. Indicate positive and negative aspects of thermoregulation when housing dairy cows indoors.
Positive: Easy access to feed (no need to search) and protection against poor weather conditions.
Negative: Hard to adjust to changes in climate conditions, high infection pressure, and difficult to avoid contact with
pen mates.
3. Indicate which changes in performance can be measured when individually housed pigs are placed
together in a group.
Behavior: There will be fighting at the beginning until the hierarchy is determined.
Hormone levels: Increase in stress hormone levels, such as cortisol.
Fertility: Stress occurring during and after regrouping sows that are early in gestation can lead to a higher embryonic
