Reproduction Physiology Flashcards
What is puberty?
The age at which an animal becomes capable of reproduction
When a female hits puberty she goes into
heat (standing heat)
When a male reaches puberty he now has a
libido (sex drive)
erection
penetration
ejaculation
What is sexual maturity
The age at which animals can reproduce at optimal level
When does a heifer reach sexual maturity
15 months
When does a bull reach sexual maturity
2-3 months from puberty to sexual maturity
How many cows does a young and mature bull breed
Young bull: 15 cows/season
Mature bull: 40 cows/season
What are the 5 stages of reproduction
Parturition
Gestation
Lactation
Rebreeding
Hormonal Control
Define parturition
act of giving birth
Define gestation
period of time from mating to parturition
Define lactation
period of time producing milk
What is the estrous cycle
period of time between (about three weeks for most farm animals)
What are the 5 signs of standing heat
- Will stand to be ridden (hormones can cause homosexual behavior)
- Discharge
- Swollen vulva (reddens)
- Nervousness
- Vocalizes
length of estrous cycle of a cow
21 days
length of estrous cycle of a ewe
17 days
length of estrous cycle of a sow
21 days
length of estrous cycle of a mare
22 days
Length of estrus in a cow
18 hr
Length of estrus in a ewe
30 hr
Length of estrus in a sow
60 hr
Length of estrus in a mare
7 days
Gestation length of a cow
283 days
Gestation length of a ewe
147 days
Gestation length of a sow
114 days
Gestation length of a mare
343 days
Proestrus and estrus is the
follicular phase (20% of estrus cycle)
Estrus allows the male to
mount
FSH and LH recruit
follicles, follicle enlarges & estrogen increases
During estrus, what decreases?
estrogen
During estrus, LH surge, then
ovulation 24-48 hr later
During estrus, what is high and what is towards the oviduct?
uterine motility is high and contractions toward oviduct
During estrus, sperm transport is
optimal
What increases during estrus?
cervical mucus volume
What is the luteal phase?
from ovulation until CL regression
80% of estrus cycle
What is diestrus?
Longest phase and there is no sexual receptivity
During the diestrus stage, ___________ is high, uterus releases _________, _____ is low, ________ _________ is present but regresses at end if female isnt present
progesterone is high
uterus releases PGF2a
corpus luteum present
What does the diestrus stage end with
luteolysis
What is flushing?
a feeding strategy to increase the ovulation rate which means increase feed intake just prior to estrus
What is seasonally anestrus controlled by?
photoperiod and temperature
When does mares cycle
in the spring and conceive before hot summer weather
When do ewes cycle?
in the fall
In ewes what must be present before E2 for behavioral estrus
P4
What is luteolysis
irreversible degeneration of CL
When do you want to inseminate an animal?
Prior to ovulation
In embryogenesis the 1st diploid cell is called a
zygote
What are morula during embryogenesis?
solid, compact mass of 16 or more cells
Totipotent (embryogenesis)
embryonic cells within the first couple of cell divisions after fertilization
Blastocyst (embryogenesis)
forms after blastomeres undergo compaction
(provides nutrient to embryo)
Trophoblast cells (embryogenesis)
formed during 1st stage of pregnancy (4 days after fertilization)
Trophoblast cells form outer layer of _________ and are a large part of the _________
blastocyst
placenta
ICM (embryogenesis)
inner cell mass or embryoblast
mass of cells inside blastocyst that gives rise to definitive structures of fetus
If placentomes do not separate post parturition the animal may have a
retained placenta
Three parts of the placenta
Amnion
Chorion
Allantois
What makes up the cows placentome
maternal caruncle + fetal cotyledon
Stage 1 of Parturition
Fetal Adrenal Cortisol released in response to stress
Increase E2 and P4
Placental PGF2a- increase uterine contractions
Cervical pressure- increase oxytocin
Stage 2 of Parturition
Expulsion of fetus
Stage 3 of Parturition
Expulsion of Placenta
Reproductive Hormones in the Anterior Pituitary
FSH & LH
Reproductive Hormones in the Hypothalamus
GnRH
Rep. Hor. in the Ovary
Estrogen (E2) and Progesterone (P4)
Rep. Hor. in the Uterine
Prostaglandin (PGF2a)
Origin, Structure, and Action of FSH
Anterior Pituitary
Glycoprotein
Initiates a new follicular wave
Origin, Structure, and Action of LH
anterior pituitary
glycoprotein
initiates ovulation
Origin, Structure, and Action of GnRH
Hypothalamus
Peptide
signs release of LH & FSH
What is the signaling mechanism for FSH & LH to go (the precursor)
GnRH
Origin, Structure, and Action of Estrogen
Dominant follicle (ovary)
Steroid
responsible for behavioral signs of estrus and suppresses FSH
Origin, Structure, and Action of Progesterone
Corpus Luteum (ovary)
Steroid
maintains pregnancy
Origin, Structure, and Action of Prostaglandi n F2a
uterus
elicosanoid (UFA derivative)
lyses CL, uterine contractions
Origin and Action of Adrenal Cortisol
Fetal Adrenal Glands
released from fetus as part of stage 1 of parturition
Origin, Structure, and Action of Oxytocin
Hypothalamus
Peptide
Uterine contractions, milk letdown
What hormone is the milk ejection reflex
Oxytocin