Pregnancy & Parturition p1 Flashcards
Embryo
Developed egg
Gestation period
Length of pregnancy
Implantation
Egg into the uterus
Capacitation
Series of changes spermatozoa undergo in the female reproductive tract
- OR -
When the sperm becomes capable of fertilizing
Chorion, allantois, amnion, urachus, cotyledons
First trimester:
Second:
Third:
- Embryonic period.
- Placenta develops. - Fetal period.
- Body tissues, organs, & systems develop. - Fetal growth period.
Fertilization in…
1. Most species
2. Mares, sows, bitches
Sperm is placed in the…
- In most species, the sperm is placed in vagina during copulation.
- The sperm is placed in the cervix/uterus
___ release stimulates the female reproductive tract to contract in waves to more the sperm into the oviduct
Oxytocin
T/F: The oviduct is the site of fertilization for most species
True
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.
- Acrosome reaction
- Vitelline membrane
Zygote
- A fertilized egg
- A diploid cell as a results of two haploid gametes
A male pronucleus is…
And a female pronucleus is…
- Nucleus of the fertilizing spermatozoon (only contributes X or Y)
- Nucleus of the fertilized ovum (only contributes X)
Male and female pronucleus join together and make a ___ chromosome number.
This cell begins mitosis to form a ___ & then ___.
- Diploid chromosome number
- Morula & then blastula
Blastula
An animal embryo at the early stage of development when it is a hollow ball of cells
Morula
A solid ball of cells resulting from division of a fertilized ovum, and from which a blastula is formed
Artificial insemination (AI) species use:
Cow
Poultry
Swine
Horses
Beef
Sheep
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
T/F: Artificial insemination is allowed for thoroughbreds horses
False! It is not allowed for registered thoroughbred horses
What are some reasons to use estrous synchronization? (3)
- AI - decrease expense of time and labor for detection of estrus
- Success of embryo transfer
- Decreased labor when young are born
Estrous synchronization, what is it?
Controlling estrus cycle so females express estrus around the same time
Name two methods of estrus synchronization
- Hormonal: induced ovulation; restart estrous cycle; suppress estrus
- Natural - weaning (sows & beef cattle)
What is embryo transfer (ET)?
Transferring fertilized embryos from one female to another
How is embryo transfer used? (3)
- Super ovulate & inseminate donor cow
- Synchronize estrus of recipient females
- Flush embryos of donor & transfer to recipient or freeze
Why use embryo transfer? (2)
- Maximize use of superior genetics
- Many offspring/female/year
T/F: Maternal reproductive tract must “recognize” pregnancy in most species in order to maintain the progesterone secreting corpus luteum
True!
Do embryos secrete hormones?
Yes! They do this to prevent the maternal release of PGF2a
What is the minimum number of embryos that must be present in a sow for there to be pregnancy recognition?
Four
T/F: Embryos move about a great deal within the uterus prior to implantation
True!
Why do embryo move around in the uterus before implantation? (2)
- Migration contact improves pregnancy recognition!!
- Allows for adequate spacing between multiple embryos
Implantation occurs when enzymes produced by blastocyst ___ away a small pit in the endometrium. The blastocyst attaches to the ___ in this pit.
- Dissolve
- Endometrium
- Placentation is…
- Arrangement of placental membranes allows transfer of (3)
- The development of extraembryonic membranes or placenta
- Allows:
- Nutrients from dam to fetus
- Wastes from fetus to dam
- No interaction of blood supply between dam & fetus
