Swine 2b Flashcards
What structure helps collect oocytes?
The infundibulum
Where does fertilization occur?
Ampullary-Isthmic junction
Where is the site of semen deposition?
The interdigitating pads
Where is GnRH released from?
the hypothalamus
What does GnRH stimulate? To do what?
It stimulates the gonadotroph cells in the anterior pituitary to release FSH and LH
What do granulosa cells secrete? What does it do?
Inhibin to privide negative feedback on the anterior pituitary
What do granulosa cells convert?
Androgens to estrogens
What do thecal cells secrete?
androgens
What do estrogens do?
Mature follicles and provide negative feedback at the hypothalamus and anterior pituitary
When do estrogens provide positive feedback to the hypothalamus?
When there is a mature follicle, estrogens are secreted and act on the surge center to increase GnRH release and stimulate the LH surge
What is a primordial follicle?
A microscopic follicle where the oocyte is surrounded by a single layer of squamous cells. It is immature and the smallest follicle in the ovarian cortex.
What is a primary follicle?
An oocyte surrounded by a single layer of cuboidal cells - it is the resting stage and the stage of the majority of follicles
What is a proliferating primary follicle?
Increase in size of oocyte and height of follilcar cells
What is a secondary follicle?
A follicle surrounded by several layers of follicular (granuloca cells) - there is no antrum
What is a tertiary follicle?
A follicle that forms a fluid filled cavity. There is differentiation of several distinct cell layers in the follicle wall
What is a graafian follicle?
a follicle that is near ovulation
When does a corpus hemorrhagicum form? What are the E2 and P4 levels like at this point?
During a metestrus phase: decreased E2 and increased P4
What structure is formed when estrogen is at the minimum and progesterone is at the maximum?
Corpora lutea
What is anestrus?
When the female is not cycling - there is no expression of heat over time
When does proestrus occur?
During day 17-20 of the estrous cycle
Generally, what occurs during proestrus?
The CL is undergoing regression, progesterone levels fall which allows for final follicular development
Specifically, what occurs during proestrus?
Tertiary follicle(s) and oocytes undergo final maturation
Estrogen levels increase
Dominant follicles are in the Graafian stage FSH and LH stimulate final maturation
The female becomes receptive
What does estrogen do during the proestrus stage?
It prepares the uterus and oviducts for sperm transport and fertilization (smooth muscle contractions and cilia movement)
It initiates uterine changes for later embryo development (uterine galnds and oviduct secretion
What is the difference in ovulation between pigs and cows?
Pigs can ovulate when showing signs of heat
When does estrus occur?
Day 0 of the estrous cycle - it is the day of standing heat
How long does estrus last?
24-72 hours
When does metestrus occur?
During day 2-4 of the estrous cycle
When does the embryo move into the uterus? What does it do prior to this?
It partially develops in the oviduct and moves into the uterus at approximately day 4-5
When does embryo implantation occur?
around day 11 or 12
When is diestrus?
Day 5-17 of the estrous cycle
When is the corpus luteum at its maximum size and mature?
Day 12 of the estrous cycle
What hormone dominates during diestrus?
progesterone
How many embryos do you need for maternal recognition?
At least 2 embryos in each horn
If there is maternal recognition, what happens to the CL?
there is no regression
If there is not maternal recognition, what happens to the CL?
The uterus releases prostaglandin to cause CL regression
If the CL regresses, what occurs?
Progesterone in the blood decreases and Graafian follicles begin final development that occurs in proestrus for ovulation at estrus.
The follicular phase is the phase of the female estrous cycle when she is under ______ stimulation.
estrogen
The luteal phase is the phase of the female estrous cycle when she is under _______ stimulation.
progesterone
Define maternal recognition of pregnancy.
Chemical message (usually hormonal) which results in maintenance of the CL. Either through inhibiting prostaglandin production from the endometrium, preventing release from uterus or protecting CL from prostaglandin effects
What do aflotoxins from corn cause in pigs?
Pseudopregnancy and early embryonic death
How is aflotoxin ingestion treated?
Get off of moldy corn and give prostaglandin
a.
ovulation
b.
fertilization
c.
Corpora lutea produce progesterone
d.
blastocysts hatching and entry into the uterus
e.
Conceptus elongation and production of estrogen and IL-1
f.
attachment and implantation
g.
115 days of gestation
h.
Corpora lutea lysed via uterine prostaglandin
i.
new follicular growht
j.
corpora lutea maintained throughout gestation
Seasonally infertility coincides with increased environmental temps during what months?
July-September
Reduced farrowing rates occur during what months?
November-December
When does heat stress occur?
When energy is generated by an animal is unable to dissipate due to increased environmental temperature
How much does heat stess cost the swine industry annually? Why?
$900 million dollars due to reduced reproductive capacity, reduced growth rates, changes to carcass composition, and increased mortality
When does normal sperm production decrease?
When ambient temperature increases and remains above 29 degrees C for as little as 48 hours
When does fertility in the boar reach its lowest point in relation to temperature increase?
3-6 weeks after the initial increase in temperature
When are decreases in sow fertility greatest?
When bred to boars 4 to 6 weeks after exposure to high temperatures
What are the recommendations for management of a boar that interacts with ambient temperatures greater than 28 degrees C?
Cool the boars - evaporate cooling, drip cooling, or shade or wallows for boars housed outside
