Pregnancy & Parturition p1

Question 1

Embryo

Answer 1

Developed egg

Question 2

Gestation period

Answer 2

Length of pregnancy

Question 3

Implantation

Answer 3

Egg into the uterus

Question 4

Capacitation

Answer 4

Series of changes spermatozoa undergo in the female reproductive tract
- OR -
When the sperm becomes capable of fertilizing

Question 5

Chorion, allantois, amnion, urachus, cotyledons

Question 6

First trimester:
Second:
Third:

Answer 6

1. Embryonic period.
   - Placenta develops.
2. Fetal period.
   - Body tissues, organs, & systems develop.
3. Fetal growth period.

Question 7

Fertilization in…
1. Most species
2. Mares, sows, bitches
Sperm is placed in the…

Answer 7

1. In most species, the sperm is placed in vagina during copulation.
2. The sperm is placed in the cervix/uterus

Question 8

___ release stimulates the female reproductive tract to contract in waves to more the sperm into the oviduct

Answer 8

Oxytocin

Question 9

T/F: The oviduct is the site of fertilization for most species

Answer 9

True

Question 10

As sperm attach to the zona pellucida of ovum a series of events called the ____ reaction occur.
The acrosome enzymes digest a path thru the zona, the sperm enters and fuses with the ___ membrane.

Answer 10

1. Acrosome reaction
2. Vitelline membrane

Question 11

Zygote

Answer 11

• A fertilized egg
• A diploid cell as a results of two haploid gametes

Question 12

A male pronucleus is…
And a female pronucleus is…

Answer 12

1. Nucleus of the fertilizing spermatozoon (only contributes X or Y)
2. Nucleus of the fertilized ovum (only contributes X)

Question 13

Male and female pronucleus join together and make a ___ chromosome number.
This cell begins mitosis to form a ___ & then ___.

Answer 13

1. Diploid chromosome number
2. Morula & then blastula

Question 14

Blastula

Answer 14

An animal embryo at the early stage of development when it is a hollow ball of cells

Question 15

Morula

Answer 15

A solid ball of cells resulting from division of a fertilized ovum, and from which a blastula is formed

Question 16

Artificial insemination (AI) species use:
Cow
Poultry
Swine
Horses
Beef
Sheep

Answer 16

Cow: 70%
Poultry: 95% of turkeys, chickens use natural
Swine: >80%
Horses: Increasing w/more use of extended semen
Beef: <10% but increasing
Sheep: Increasing but limited, flocks dispersed

Question 17

T/F: Artificial insemination is allowed for thoroughbreds horses

Answer 17

False! It is not allowed for registered thoroughbred horses

Question 18

What are some reasons to use estrous synchronization? (3)

Answer 18

1. AI - decrease expense of time and labor for detection of estrus
2. Success of embryo transfer
3. Decreased labor when young are born

Question 19

Estrous synchronization, what is it?

Answer 19

Controlling estrus cycle so females express estrus around the same time

Question 20

Name two methods of estrus synchronization

Answer 20

1. Hormonal: induced ovulation; restart estrous cycle; suppress estrus
2. Natural - weaning (sows & beef cattle)

Question 21

What is embryo transfer (ET)?

Answer 21

Transferring fertilized embryos from one female to another

Question 22

How is embryo transfer used? (3)

Answer 22

1. Super ovulate & inseminate donor cow
2. Synchronize estrus of recipient females
3. Flush embryos of donor & transfer to recipient or freeze

Question 23

Why use embryo transfer? (2)

Answer 23

1. Maximize use of superior genetics
2. Many offspring/female/year

Question 24

T/F: Maternal reproductive tract must “recognize” pregnancy in most species in order to maintain the progesterone secreting corpus luteum

Answer 24

True!

Question 25

Do embryos secrete hormones?

Answer 25

Yes! They do this to prevent the maternal release of PGF2a

Question 26

What is the minimum number of embryos that must be present in a sow for there to be pregnancy recognition?

Answer 26

Four

Question 27

T/F: Embryos move about a great deal within the uterus prior to implantation

Answer 27

True!

Question 28

Why do embryo move around in the uterus before implantation? (2)

Answer 28

1. Migration contact improves pregnancy recognition!! 2. Allows for adequate spacing between multiple embryos

Question 29

Implantation occurs when enzymes produced by blastocyst ___ away a small pit in the endometrium. The blastocyst attaches to the ___ in this pit.

Answer 29

1. Dissolve 2. Endometrium

Question 30

1. Placentation is... 2. Arrangement of placental membranes allows transfer of (3)

Answer 30

1. The development of extraembryonic membranes or placenta 2. Allows: - Nutrients from dam to fetus - Wastes from fetus to dam - No interaction of blood supply between dam & fetus