Pregnancy in pigs

Question 1

Explain the steps of early pregnancy

Answer 1

1. Fertilization
2. splitting
3. cleavage
4. early emrbyonic development
5. implantation

Question 2

Explain the 1st stage: fertilization

Answer 2

The sperm is attaching to the surface of the zona pellucida of the oocyte, the head is penetrating and the pronucleus is formed

Question 3

Explain the 3rd stage: Cleavage

Answer 3

During cleavage the 2-cell embryo will develop into the morula. We will have a blastocyst formation, the zona pellucida disappears (= hatching) then the embryos are starting to migrate in the lumen of the uterine horns finding their position there which is parallel to the conceptus expansion

Question 4

What is the cleacage?

Answer 4

Cleavage is the division of cells in the early development of the embryo. One cell embryo undergoes a series of cleavage divisions, progressing through 2-cell, 4, cell, 8-cell and 16-cell (also called morula). After the 2-cell has divided into 4-cell, they will travel from the fallopian tube – oviduct, to the uterine tip and they are staying there until day 5-6.

Question 5

what is the morula?

Answer 5

The morula is the cell that has the omnipotent blastomeres, which can develop into anything in the future individuals. The first differentiation is the morula blastocyst development.

Question 6

How many hours for the zygote to develop?

Answer 6

8 hours

Question 7

How many hours for the 2-cell embryo to develop?

Answer 7

24-26 hours

Question 8

How many hours for the 4-cell embryo to develop?

Answer 8

26-32 hours

Question 9

When is the 4-cell embryo entering to the uterus?

Answer 9

50-56 hours after ovulation

Question 10

when does the blastocyst formation happen?

Answer 10

On day 5-6

Question 11

When is the hatching of the blastocyst happening? and what does hatching mean?

Answer 11

Hatching = Zona pellucida opens and disappears

It happens from day 6

Question 12

when does the placentation take place?

Answer 12

From day 12-13

Question 13

How long is the pregnancy of a pig?

Answer 13

112-115 days
3months, 3 weeks and 3 days

Question 14

What is the implantation?

Answer 14

It is also called placentation.

The implantation of the conceptus is non-invasive, meaning 6 histological layers between the maternal and foetal circulation that don’t allow the immunoglobulins directly to the intrauterine life.
the implantation is regulated by the mother and mainly by the embryo. On the mothers side, the progesterone and the oestrogen is giving signal to the mother that she is pregnant.

Question 15

How fast is the growing of the foetus?

Answer 15

fast. the 2mm spherical feature develops to a 10 mm long tubular feature on day 11-12.
2-3 hours latet the elongation speed is quite
fast = 30-40 mm/h

Question 16

name the diffeernetiation of the cell

Answer 16

Ectoderm
Mesoderm
Endoderm

Question 17

What does the ectoderm develop?

Answer 17

skin, hair, mammary gland, nervous system

Question 18

What does the mesoderm develop?

Answer 18

heart, blood vessels, kidneys, bones, muscles, reproductive (urogenital) organs, connective tissue, adipose tissue

• Endoderm – liver, pancreas, epithelial layer of gastrointestinal organs, respiratory system

Question 19

What does the endoderm develop?

Answer 19

liver, pancreas, epithelial layer of gastrointestinal organs, respiratory system

Question 20

When can we measure of the sow is pregnant, and how?

Answer 20

We measure the progesterone concentration after day 15, before day 15 it could still be high due to the oestrus cycle

Question 21

Why/how is it possible for us to give a rate of false pregnancy diagnosis?

Answer 21

Aprox 20% will not develop. But the other 80% may not also attach, and the sow will have a 100% embryonic mortality and therefore we can give a false diagnosis

Question 22

What are some economical principals for pregnancy in swine?

Answer 22

To reduce false diagnosis, it should be reliable, practical and simple.

Immediate result should be given

Question 23

What happens if the sow does not take? (not pregnant)

Answer 23

it is common to give the pig one more chance, after 2nd unsuccessful IA she is culled.

The non-return sows should be checked at day 28-30 by an ultrasound if she is pregnant, it might not be, because she could have gone through heat silently.

Question 24

How long is the oestrus cycle?

Answer 24

21-23 days

How long it takes for the pig to be in heat again

Question 25

When can we check for pregnancy, and what is important that the sow do before this?

Answer 25

We can check on day 26-30.

After the IA the pigs should be kept in an individual cage for a month (26-30 days), after that we can check for pregnancy and after the pig can go out or be re-inseminated

Question 26

Name some methods to check for pregnancy:

Answer 26

Rectal palpation: Forget it. An existing method, we find the uterine artery

Endocrine diagnosis: Estron-sulphate test and the progesterone test, they can give a good information after day 24-26. But waiting so long, we can wait a few days longer and then do the ultrasound

Histological sample from the vagina: Check the thickness of the epithelial layer, but this is not done a farm level observation

Question 27

What type of placenta does the pig have?

Answer 27

Diffuse placenta

A placenta made up of villi diffusely scattered over almost the whole surface of the chorion

Question 28

What kind of feed is important to give to the sow half-way into the pregnancy and why?

Answer 28

Half into the pregnancy there will be a rapid quantity weight gain of the foetuses, the tissues grow (the organs are finished developed)

It is demanding, so the sow demand a huge maternal feed so the sow will have a different feed after this time: high quality, high protein + minerals, and high energy is needed in the feed.

Question 29

What is a farrowing unit and when should it be implented?

Answer 29

It should provide physical comfort for the young nursing pigs and for the sow

4-7 days priort to the expected term

Question 30

“all in-all out” system. What is it and when is it used?

Answer 30

Often used at the farrowing unit, it means it should be filled by everyone at the same time and they should all leave at the sime time.

Question 31

Before filling the farrowing unit, what is important to do?

Answer 31

We have to clean the building and the sows before they can enter.

It is advised to give them straw (could be anything dry), some kind of litter material, so the sow right before farrowing can prepare her nest

Question 32

When can we expect the farrowing to happen?

Answer 32

There could be a 2-3 days range from the exact due date. We try to avoid farrowing on weekends and on holidays, such as Christmas, easter.

Question 33

How many phases is the farrowing divided into? name them

Answer 33

3 phases

Preparation, birth and final phase

Question 34

What is the 1st phase of farrowing?

Answer 34

1. 1st phase – preparation

We can see the milk in teats.
The sow eat less, we give only small portions of feed and water. We can observe a hard abdominal wall, the sow lays in a lateral position, they are uncomfortable: standing up, laying down, moving a bit.

We can also see some abdominal contractions of the muscular layer. The body temperature is slightly reduced, but it wont be measured.

The cervix is opened, the vulva is reddened and amnionic fluid can be seen and the farrowing will start shortly after the fluid appears.

Question 35

What is the 2nd phase of farrowing?

Answer 35

2. 2nd phase – Birth (main phase)
   Farrowing

The abdominal and the myometrial contractions are more frequent, more synchronized and the first piglet will appear very quickly.

the piglets are coming out alternately (from right uterine horn, left uterine horn, right, left osv).
The interval between two piglets is between 10-30 minutes, and the total farrowing last from 2 hrs to 8 hrs, some breeds are faster.

The small piglets will find the teat alone, but in some cases they cannot, and we should assist them.

Question 36

What is the 3rd phase of farrowing?

Answer 36

3. 3rd phase – Final phase
   The terminate phase.
   The birth of the placenta, it should come out after 1-5 hrs.

The fluid of the uterine lumen is also coming out, it should take 1-2 days. Right after the birth of the last piglet, we already have the beginning of involution.

Question 37

What is the starting point of the involution called and how long does it last?

Answer 37

Puerperium

It is the starting by the pint of involution and last to the fertilizing stage of the sow, til the sow is completed for the next fertilization, this will be from 28-40 days

Question 38

What is the involution?

Answer 38

the pregnant uterus returning to its pre-pregnancy state - closing of the cervix

Question 39

What happens if the cervix isn’t closed after 3 days?

Answer 39

There is a chance for bacteria and infection

Question 40

Why dont we force the closing of cervix with drugs?

Answer 40

Because we want the lochia to exit the uterine lumnen and the myometrial contractions make sure it does

Question 41

What is the remenants of the pregnancy called?

Answer 41

Lochia

Question 42

Which type of problems can occur during farrowing?

Answer 42

• Weak contractions: give oxytocin
• “jam” at the bifurcation
• Sow could be aggressive
• Prolapses

Question 43

Give two examples of methods that are used to induce a better involution and a longer suckling period, increasing the quality of the piglets.

Answer 43

The piglet is removed from the mother for some hours of each day, to trick the endocrinology system of the sow – some kind of weaning. She will then come in heat, and be inseminated. By doing this, the piglets can have a longer weaning by some weeks – increasing the quality of the piglets.

The second method is called the kinder garden: From week 3 we open the door only for the piglets, they are coming out and gather all in the middle. They will get to know each other, and when we group them in the rearing unit (dangerous age of the piglet) they will all know each other this way there won’t be fighting.