Dairy Cow Week 3 Study Questions Flashcards
What is the name of the device that is used to collect semen from a bull?
artificial vagina
What five criteria are used in semen evaluation?
-ejaculate volume
-sperm concentration
-total sperm ejaculate
-progressive motility
-morphology
What are the components of a sperm extender and what are their purpose?
-salt, buffer, egg or milk (protect during cooling)
-glycerol (protects from freezing)
-glucose (energy for sperm)
-antibiotic
How is semen packaged and stored for long-term storage?
Frozen
What is “sire conception rate”?
the probability that a bull’s semen would get a heifer pregnant
What is “gender selected semen”?
sperm that has been sexed
Advantages of gender selected semen
-90% of calves born will be female (replacement heifers)
-Cows you do not want to use to generate replacements can be inseminated with beef semen (dairy beef)
Disadvantages of gender selected semen
-More expensive than conventional
($20-not sexed vs $40-sexed)
-Fertility to AI is lower
What is the basis for separating X and Y semen using a flow cytometer?
X chromosomes are heavier
–> X chromosomes will make girls
What is estrous synchronization?
Injecting cows or heifers with PGF 2a so that the group of heifers come into heat (estrus) on the same day
What are three important things to know about PGF2α treatment for estrous synchronization?
-Will not regress the CL during first 5 days of the estrous cycle
-Heifers in heat 2 to 3 days after treatment
-Cows in heat 3 to 5 days after treatment
Diagram/understand a program that uses two PGF2α treatments for estrous synchronization in heifers.
-Give PGF 2 a
–> 2-3 days check heat and AI
(Get about 70% of the heifers)
-After 14 days give the other 30% a PGF 2a dose
–> 2-3 days check heat and AI
When (relative to estrus and ovulation) do we AI heifers and cows? Why?
Breed (AI) 12 hours before she ovulates
-So sperm can capacitate and get to oviduct
Where is semen placed in the repro tract when a cow or heifer is AI?
body of the uterus
Where does fertilization occur in the female repro tract?
the oviduct
When does the fertilized embryo enter the uterus?
Embryo remains in the oviduct until day 5 when it enters the uterus
Stages of early embryonic development from one cell to tubular embryo.
-Early cleavage stages: 1, 2,3,4 8, and 16 cell
-Morula (compact ball of cells)
-Blastocyst
-Hatched blastocyst
blastocoel
the fluid-filled cavity of a blastula.
inner cell mass
gives rise to the tissues of the embryo proper
–> The ICM is a cellular mass on one side of the hollow interior of the round embryo,
trophoblast
a layer of tissue on the outside of a mammalian blastula, supplying the embryo with nourishment and later forming the major part of the placenta.
What are the two cellular layers of the uterus?
-Outside layer: myometrium
-Inside layer: endometrium
What do uterine glands do to help the embryo survive?
lands nourish the embryo → histotroph, nutrients
What is interferon tau and how does it act to maintain the CL?
a hormone that blocks PGF2α release
from the uterus and rescues the CL
to maintain progesterone and
pregnancy.
Parts of the placenta
-Cotyledons ( fetal placenta attachment points)
-fetus
-Amnion and amnionic fluid
-Placental arteries and veins
-Chorioallantois Allantoic fluid
How are the bovine placenta and the human placenta different?
bovine placenta does not implant like human placenta
Why doesn’t a pregnant cow come back into heat 21 days after breeding?
Progesterone keeps the cow from coming back into heat.
What are three ways that you could diagnose pregnancy in a cow?
-Ultrasound
-Fluid : blood or milk
-Lateral flow test
What are pregnancy-associated glycoproteins (PAG)?
show up 25 days into pregnancy
When talking about pregnancy diagnosis, what is a “recheck”?
(approx 60 to 80 d after AI)
-Blood or milk PAG
-Palpitation
-Ultrasound – fetal sexting
What is the difference between stroma and parenchyma in the mammary gland?
Stroma: supportive connective tissue
Parenchyma: glandular secretory (milk producing) tissue
