Exam 4 Flashcards
Progesterone Pregnancy Functions
-inhibits uterine contractions
-stimulates uterine secretions
-creates cervical plug
-mammary gland development
-species variation
Estrogen Pregnancy Functions
-stimulates the endometrium to increase blood flow and secretions
-needed for events leading to parturition
-mammary gland development
Estrogen sources during pregnancy
-follicles on ovary continue to grow during pregnancy
-placental membranes are the major source of estrogens for all species during pregnancy
Where does progesterone come from during gestation in sow?
It comes from the CL throughout the entire pregnancy
Where does progesterone come from during gestation in the doe?
It comes from the CL throughout the entire pregnancy
Where does progesterone come from during gestation in the ewe?
It comes from the CL in the first 40 days
It comes from the placental membranes in the last 100 days
Where does progesterone come from during gestation in cow?
It comes from the CL in the first 128 days
It comes from the placental membrane after day 128
Where does progesterone come from during gestation in the mare?
-the original CL from 35 days
-the accessory CL from days 40-180
-the placental membranes after day 160-180
Equine Accessory CL
-Stimulated by production of equine chorionic gonadotropin (ecg)
ECG
-produced by the endometrial cups
-invasion of endometrium by chorionic girdle cells of the embryonic vessilve
-increased follicular development and formation of many CL
Advantages of AI
-superior male genetics available
-reduces chance of sexually transmitted diseases
-increased coverage by selected sire
Disadvantage of AI
-increased labor costs
-requires skilled labor and periods of intensive management
-requires adequate facilities
-higher input costs
Dairy Industry AI
-90% national cow herd bred AI
Beef Industry AI
<12% national cow herd bred AI
-greater use in purebred operations or special projects
Swine Industry AI
-use is increasing
-struggle is keeping crypreserved semen alive
-now chilled not frozen semen is used
Swine is NC >90% AI
Equine Industry AI
Challenges with cryopreserved semen
Breed standards for certain things like Kentucky derby the horses must be bred by live cover
Site of Semen Deposition in NM vs AI
AI-must be in the uterus and bypasses cervix
NM-site varies by species
Ejaculate amount in NM vs AI
NM-entire ejaculate is used on one female
AI-entire ejaculate is extended on several females between (3-500)
Timing of mating between NM vs AI
NM-during estrus
AI-estrus or beginning of metaestrus to find the right time when ovulation occurs
Number of inseminations in NM vs AI
NM-one and done
AI-multiple inseminations usually twice
Cow insemination technique
yo have to find the cervix then weave through the annular rings, the struggle is making sure you don’t go through the fornix instead making sure to inseminate in the uterus instead of the uterine horn
Mare insemination technique
transvaginal with finger to find the cervical oss, making sure there is extra liquid with the insemination to prevent back flow
Sow insemination technique
-simple but must make sure it is turning the right way to get in through the corkscrew into the uterus
Sexed semen
-ability to separate x and y sperns
-allows for female heifers
not all sires can because since it takes so long to process there is a risk of sperm death
Advantages of Sexed Semen
1.) Breed Heifers. with X sperm to decrease calving difficulties
2.) Eliminate biosecurity risks with closed herd expansions
3.) On average 9 out of 10 calves will be of the desired sex
Disadvantages of Sexed Semen
-Cost is approximately $30 more per straw
-Reduced fertility and conception rates
-much higher conception rates when used with heifers
Pregancy rates with bulls vs AI
-bulls have about a 60% pregnancy rate which is similar for many timed AI programs
-bulls may be better at clean up and catching cows that are not synchronized
Embryo Transfer
-Method for propagation of superior females
-Superovulation allows for multiple possible embryos in one round
-can either fresh transfer embryos or freeze embryos
Superovulation
-ultimatley want to keep more follicles alive
-block folliculogenesis
-use FSH or different forms
Superovulation protocol for the donor female
9 days after estrus FSH is given twice a day from day 9-12 but with decreasing dosage
-on day 11 pdf is given to kill CL and allow for estrus to start
day 13 is estrus and they are inseminated on day 13 and 14
-day 20 is when embryos are recovered
SUpovulation protocol for recipient female
=PGF day 10
-Estrus day 13
-recieves embryos day 20
What is done after the embryos are recovered to the donor female
given pgf to drop progesterone to make sure they don’t stay pregnant if some embryos are missed
Uterine-embryo synchrony
fertility decreases if uterine environment and stage of embryo development are not synchronized
Bovine Embryo Transfer expected results
-average 5-6 embryos per flush
but can range from 0-30 embryos per flush
Pregnancy rates following transfer
-fresh transfer-60%
-frozen embryos-40-50%`
What is in vitro embryo production used for
-applied animal biotechnologies
-research
-propagation of superior fences
-increased flexibility for sire selection
-treatment for clinical infertility
Production of Embryos In Vitro
-oocyte-cumulus complexes aspirated from 2-10 mm antral follicles
-aspirated complies collected from sediment
-oocyte-cumulus complexes washed
-cultured for 20h(oocyte maturation)
-sperm prepared from frozen semen
-swim-up used to select motile cells
-must be capacitated in vitro
-insemination (18h)
-vulture for 7 dyas
-culture to blastocyst stage
-transfer to recipient female
IVF Profuduction (abbatitoir) ~ 100 ovaries
-150-180 ova for in vitro maturation
-gertilization rate >90-95%
-143 one cell embryos
-tranferable embryos 35-45%
-60 embryos
-blastocysts at 7 days 25-30%
-45 embryos
IVF Production (transvaginal)
-single aspiration(both ovaries)
~10 ova for IVM
-Blastocyst at 7 days
~1-2 embryos
-number of aspiration 1-2/week
Embryo grades
embryos are graded based on the amount of fragmentation (lower grade the better)
0-none
1-up to 10%
2-10-25%
3->25%
IVF Calfs
-increased birth wwights
-faster growth rates
-more saleable carcass
-dystocia
-health problems
Somatic Cell Nuclear Transfer
-method for producing a series of “identical” individuals
-clones are genetically identical but are nor always physically identical
-clones can vary in age (if frozen)
Step 1 in cloning
-remove DNA from Metaphase II oocyte
-“enucleated oocyte”
Step 2 in cloning
remove cells for donor animal
Step 3 in cloning
fuse donor cell with inculcated oocyte using electrical pulses to incorporate the DNA into the cytoplasm
-Donor DNA reprogrammed
-cone created
Step 4 in cloning
-culture to blastocyst stage in lab
-transfer to recipient
Uses for clones
-rapid sire proof
-phatmaceuticals
-xenotransplant
-nutrapsueticals
Pitfalls with clones
-low prep rates
-some abnormally large fetuses
-some malformation
-abnormal placenta development
-increased calling difficlties
extended gestation lengths
How many generations can cloning be successful
5
What animals have been cloned
-mice.rabbits,sheep,goats,cattle, pigs, cats, mules, horses and dogs
“Dolly”
first clone from a fully mature somatic cell (mammary cell clote)
-cloned from an adult ewe
therapeutic cloning
the production of cloned cells for the sole purpose of harvesting stem cells
Embryonic stem cells
-therapuetic cloning
-tissue derived from embryo growing in vitro
-provides long term source of DNA
-can be genetically modified
can be used to grow transplant organs
invasive implantation
the chorion of the embryo berries into the uterine endometrium
Placenta protection function
-fluid cushion (skeletal system)
-placental barrier (immune system function)
-does not prevent toxins from going back and forth
Placenta nutrition function
-suppl of all energy protein, CHO, FA precursors
-removal of waste products
Placenta Respiration Function
-Carries oxygenated blood into the placenta and carries deoxygenated blood out
Placenta hormone function
-chorionic goandotropin
-progesterone
-estrogens
-chorion is responsible for making those hormones
Placentation formation
-folding over the inner cell mass to form the amnion
-chorion-fusion of trophoblast with mesoderm
-expansion of the allantois-‘extension’ of the bladder
-fusion with the chorion
Time of placenta formation in pig
formation starts in 13 days, formation in 18-24 days
Time of placenta formation in sheep
formation starts in 14-16 days formation in 28-35
Time of placenta formation in cattle
formation starts in 28-32, formation done by days 40-45
Time of placenta formation in horses
formation starts in 34-40 days formation done by day 95-150
Epitheliochoiral Placenta
-6 layers
-Has the fetal and maternal endothelium , storm, epithelium
-no transfer or antibodies between mother and fetus
-non invasive implantation
Endotheliochorial placenta
-4 layers
antibodies can pass so passive transfer of antibodies can occur
Hemochorial Placenta
3 layers
very efficient
invasive type of implantation
Diffuse Placenta
-Covers entire surface of uterus
-invasive
-chorion interlocks with uterine endometrium
Zonary Placenta
central girdle of cells
-the only transfer between maternal and fetal blood happens at the zonary band
Discoid Placenta
-disk shaped site on one side
-invasive implantation
Cotylendary Placentas
-special sites of attachment
-convex caruncles in cows
-concave caruncles in ewes
-non invasive
Placentones
where the cotelydon and caruncle attach where the maternal and fetal nutrients exchange 6 layers
Nutrients of the embryo pre-implantation
-cytoplasm of the zygote/blastocyst
-soley dependent on uterine and oviductal secretions
Pre-attachment histotrophic nutrition
-stored energy in the cytoplasm
-MRNA already in cytoplasm
-uterine gland secretions provide the precursors
-communication between embryo and uterus-synchrony reqired
Post attachment nutriotopn
-hometorophic nutrition
-selective transfer across placenta
-amino and fatty acids and glucose
-co2 and O2
-vitamins mineral and electrolyte
Factors affecting fetal growth
-genetics
-environemnt and neutron (placenta and uterus size)
-litter size (bigger litter smaller fetuses)
Sex of fetus affecting gestation length
-male calf usually 1-2 days longer than female
Number of offspring affecting gestation length
-twin calves 5-10 days less
-neonatal survival
Age of dam affecting gestation length
older ewe 1-2 days longer
Geneetics affecting gestation length
-mare abd stallion 340 days
-mare and jack 355 dyas
Season affecting gestation length
-mare bred in winter (longer)
-ewe bred in summer (shorter)
seasonally polyesters is when this comes into play
Changes in the cervix for parturition
-dialates
-occurs through synergism between relaxin and estrogen
Changes in the pubic symphysis form parturition
occurs through synergism between relaxin and estrogen
Changes in the reproductive tract uterus for parturition
-uterine contraction
-inhibiotrs like progesterone are removed
estrogen increases oxytocin receptors
-oxytocin Increases concentration and fathers PGF release to get rid of progesterone
Relaxin
-produced by CL-stored then dmped
-restructures cervix to allow relaxation and dilation’
-relaxes ligaments of pbic symphysis
changes in the mammary gland
-initiqal development at puberty
-estrogen stimulates development of duct system throughout gestation
-progesterone stimulates alveolar growth through gestation
-E2 and P4 inhibit milk production
changes the fetus with growth
-maturation of the lungs
severing of the umbilical cord intiates fetus to take first breath
-thermoregulatiob
-nutrient absorption
-immune function
control of parturition
-intitated by fetus as hypothalamus matures
-stress causes release of fetal adrenaline corticosteroids
-increased estrogen decreased progesterone
-increased oxytocin and relation.
FETAL STRESS
Initiation of Partutiton by Fetus
-hypothaamus matures and produces CRH
-anterior pituitary releases ACTH
-adrenal cortex produces steroids
-fetal placenta shifts from P4 to E2
Initiation of Parturition by dam
-gravid uterus releases PGF
-corpus lute loses P4 and releases relaxin
-posterior pituitary releases oxytocin
-uterine contractions
Signs of impending parturition
-udder development and presence of milk \
-hollowing and relaxation
-nesting
-isolation
-off feed
-colicky and discomfort
Parturitoon Prepatory Stage 1
-uterine contractions go from irregular to regular
-rotation of fetus
-dilation of cerviz
-relaxation of the pubic symphysis
Parturition stage 2 fetal expulsion
-chorioallontois ruptures
-fetus forces through birth canal
-rupture of aminion
-delivery of fetus
-then umbilical cord severed
Positive feedback loop with parturition
-pressure on cervix causes a nerve impulse to hypothalamus which cause the posterior pituitary to keep releasing oxytocin
Parturition stage 3-delivery of the mebranbes
-choriuonic villi loosen and detach
-afterbirth is shed
When are placentas typically retained
-early delivery
-disease or vitamin/mineral imbalances
-twins or triplets
How does feeding manipulation affect parturition timing
begin feeding schedule so cows eat approximately 12hrs before preferred calming time
Causes of dystocia
-small size of dam
-unusually large fetus
malpresentatons
Why induce parturition or abortion
management tool-timing
-limits fetal size
-abortion stops mosmatinh
-entry into feedlots would be inhibited if pregnant
Sow induction of parturition
PGF is drug of choice because it kills the CL
If it is done before day 110 its an abortion because piglets are not formed enough to survive
If its done after day 112 it is considered normal parturition
Ewe induction of parturition
-glucocorticoids (mimic fetal stress)
-within a week of due date
-glucocorticodids after day 40-50 will abort
-PGF before day 40 will abort
Cow induction of partition
-glucocorticoids within 2 weeks of term
-abortion in feedlot or mismated cattle
-pFD before day 150
after day 150 glucotorticoids
high indenice of retained placentas
Relaxin does not work
Induction of parurition in mares
-no good method
pdf most effective before day 150 for abortions
-past 330 days and with milk calcium of 200 pop
-use oxytocin and PGF
-repeat oxytocin until stage ii starts
Uterine involution
-trandormation from pregnant to non-pregnant sixe
-shrinkage
-muscle tone
-blood flow
-epitherlial lining
Time required for involution
diffuse faster than cotyledonary
-cattle 4-6 weeks
-sheep 3-4 weeks
swine 2-3 weeks
equine 1-2 weeks
Slowed by abnormal delivery
Resumption of estrous cycles
-lh at low frequency
-prl elevated
-opioid peptides elevated
-adrenal corticoid
-refractory periodS
Suckling affecting estrous cycle
-greater intesity=longer anestrus
nutrition effect on estrus cycle
-energy balance
-early postpartum
-magnitude of negative eb is critical
party effect on resumption of estrus cycle
-primiparous longer than multiparous
-cattle 30-40d longer
-swine 3-12 days longer
Season effect on resumption of estrous cyckle
-sheep-anestrous season
0swine-summer infertility
Postpartum fertility in coes and ewes
-short and sub functional CL in 80% of 1st cycles postpartum
-gearing system up
postpartum fertility in mare
-foal heat can be fertile
-may wait one cycle to breed
Postpartum fertility in sows
-post-farrowing heat not a true heat (behavior only)
-good fertility following weaning
Metabolic periparturient disorders
-ketosis
-milk fever
Physical periparturient disorders
-lameness
-displaced abomasum
-dystocia related injuries
Reproductive periparturient disorders
-metritis
-cystic follicles
Postpartum rebreeding in sow goal
-24 pigs/sow/year
-wean 10 pigs per litter
2.4 litters
Postpartum rebreeding sow timing
-gestation 114 days
-weaning at 18-21 days
-rebreeding has be done asap as they got to be pregnant 282 days
Postpartum rebreeding sow potential roadblock
-summer heat stresses
-cystic follicles after early weaning
postpartum rebreeding ewe/doe goal
one lambing per tear or 3 lambing per two years (2 lambs per lambing)
postpartum rebreeding ewe/doe timing
-gestiation 150 days
-weaning at 35 days
rebred within 2 cycles
postpartum rebreeding ew/doe potential roadblocks
-seasonal anestrus
-short cycles/subfunctional cl
Post partum rebreeding mare goal
-1 foal per year
postpartum rereading timing mare
-gestation 11 months
weaning 6 months
foal heat 7-10 days
Postpartum rebreeding beef cow goal
1 calf per year
Postpartum rebreeding beef cow timing
-gestation 282 days
-rebred within 90 days (heifers one month before that)
-weaning at 6 months
Postpartum rebreeding beef cow potential roadblocks
-lactational anestrus
-beef>dairy (cow presences
-summer heat stress
-short cycles/subfunctional cl
