Exam 3 Flashcards
what is the goal of estrous synchronization?
control estrus and ovulation in females so that breeding can be completed in a short period of time
Non synchronized estrus
50% get bred each cycle and with 3 cycles 88% are bred
Synchronized estrus
1 extra cycle equals 94% cows are pregnant
Advantage of average cow age with synchronized estrus
9 day advantage & 6% total pregnancy rate advantage utilizing a timed breeding program and assuming 50% AI and Natural Service conception rates
Potential advantages of estrous synchronization
-can shorten breeding and calving season
-shortened time to breeding
-utilizes labor more efficiently
-no heat checking needed
-reduced days to first service
-groups timing of parturition which means uniform offspring
What regarding cost is a disadvantage in estrous synchronization
-labor costs are increased because it requires specifically skilled labor
-much higher input costs so need to way risks and rewards
What regarding labor is a disadvantage in estrous synchronization
requires skilled labor and periods of intensive management
-multiple injections are needed
What regarding facilities is a disadvantage in estrous synchronization
-requires adequate facilities
-less time is spent observing animals
-can miss detecting non-cyclers in herd
How does prostaglandin manipulate the cycle
-decrease progesterone
-regresses cl
Restraints on prostaglandins regressing active corpus luteum
-only effective on day 5-17 corpus luteum
-no effect on days 0-5
-days 18-20 there is no corpus luteum
Hoe do progestins manipulate the cycle
blocks ovulation
How soon after PGF2a injection does the animals go into estrus
usually 2-5 days
heifers 50hrs
cows 72hrs
How many PGF2a injections need to be given
If one about 60-65% will respond
If two you will sybncronize the entire herd as the ones who did not respond will be in the luteal phase
Factors to consider with PGF2a
-animals must be cycling
-easy to use
cost 1-3$ per dose
can be combined with GnRH for timed AI
Synchronization with PGF2a
-Inject PGF on day 0
-heat check and AI days 2-7
-Inject PGF on day 12-14
-heat check and AI days 2-7
The goal of progesterone when synchronizing estrus
suppress estrus by reducing GNRH pulses thus preventing the preovulatory LH surge and also blocks behavioral estrus
Progesterone Administration for livestock species
Injection
Feed-mix in the ration
Implant-place in ear
CIDR-place in vagine
Effectiveness of the CIDR
-extremely effective and works within the hour
-while inside maintains
-once removed progesterone levels drop within 4 hours since no CL
MGA-melengesterol acetate
form of progesterone
cheapest (pennies per day)
oral administration in food
MGA disadvantages
-cows have to have supplemental feed
-they have to be fed this for a long time to make sure each cow gets enough especially the submissive cows
Norgestemate
-ear implant
-no longer on market for livestock
-too challenging and invasive
CIDR advantages
easy to use
multiple inserts can be used to alter therapeutic levels
retention rates about 95%
Recommendations for using CIDR
-implant for 7 days (enough to mimic the luteal phase)
-inject PGF on day 6 or day 7
-heat check and breed after heat for the next 3-4 days after CIDR removal
OV-Synch GNRH
On day 0-follicle turnover
(85% of cows will ovulate follicle but all will start new follicular wave)
Day 8-9 regresses CL
OV-Synch PGF
7 days after first GNRH shot
regresses the CL
OV-Synch Breed
12-16HR after GNRH shot breed. Pregnancy rates around 40%
Select synch
GnRH on day 0 then PGF on day 7 to regress CL and then heat check and breed after estrus is observed
Select Synch +CIDR
add a cidr after GNRH before OGF this will make sure the CL is maintained
Co-Synch
Day 0-gnrh shot to starta new follicular wave
Day 7-pgf to regress cl
Day 9-Gnrh to ovulate and breed at the same time for management
Co-Synch + CIDR (7 day)
Day 0-gnrh shot to starta new follicular wave
CIDR to maintain progesterone and stop ovulation and maintain cl
Day 7-pgf to regress cl
Day 10-Gnrh to ovulate and breed at the same time for management
Co-Synch + CIDR (5 days)
Day 0-GNRH for new follicular wave
Day 5-PGF
Day 5 (8hrs later)-PGF to make sure all CLs regress since so early in the cycle
Day 8-GnRH shot for ovulation and to breed.
advantages of synch methods
-shortened time to AI (10 days after start of trt)
-no heat checking needed
-reduced days to first service
-comparable to first service conception rates
Disadvantages of Synch Methods
-Drug Cost
-Multiple Injections Required
-Less time spent observing animals
-can miss detecting non-cyclers in herd
PGF2a cost
$2.00/injection
GnRH Cost
$5.00/injection
CIDR Cost
$12.00/insert
1 shot pGF2a preg rate
55%
Natural Service Preg Rate
80%
2 shot pgF preg rate
37%
CIDR PGF preg rate
45%
Select SYnch preg rate
37%
Select Synch + CIDR preg rate
53%
Co-synch preg rate
35%
Co-Syncg +CIDR (7 day) preg rate
53%
C0-SYnch + CIDR (5 day) preg rate
57%
OV-synch preg rate
29%
Advantages of using natural service to breed synchronized females
-AI not required
-No heat checking required
-good conception rates
-normal bull-female ratio used
-shortened breeding/calving season
Disadvantages of using natural service to breed synchronized females
-males should be proven sires
-BSE strongly recommended
-Bulls must be maintained through thee year
-Drug cost for synchronization
-bulls tired right after synch period
Main takeaways for estrous synchronization with cattle
1.)prostaglandins only work with cycling animals
2.)progestins and GnRH can help anestrous animals cycle. But must include prostaglandin in program.
3.) For timed AI must control follicular wave
Methods of estrous synchronizarion in sheeps and goats
-utilizing the male effect
-light therapy
-hormone therapy
Buck Effect
Strategic exposure of does to intact males will result in the ewes displaying estrus approximately 7 to 10 days.
Rams need to be isolated from doe’s sight & smell for ~60 days this procedure to be effective
Effective during short day lengths
Light Therapy in sheep and goats to suppress cyclicality
– Two months of 16-19-20 hour days
– 1-2 hr. of bright light 16 hours after dawn for 2 months
Light therapy in sheep and goats to induce cyclicity
– return to short day length;
– does start cycling in about 6 weeks
Sheep/Goats inducing estrus in breeding with progesterone supplementation
Need Progesterone supplementation for 11 to 14 days
CIDR–preferred method of progesterone supplementation
-Do not need extra hormones (eCG or PG600) to stimulate ovulation
Note: this method is optimum for getting ewes to cycle together–for uniform lamb crop
* Ewes will display estrus in 1 to 3 days following CIDR removal
Inducing estrus in the breeding season (sheep/goats) no progesterone
Make sure ewes are cycling!
– Give ewes first injection of Prostaglandin F2a (10 to 15 mg) on day 0
* Wait7to10days
– Give ewes second injection of Prostaglandin F2a (10 to 15 mg) on days 7-10
– Ewes will display estrus in 1 to 3 days following second injection of Prostaglandin F2a
* Note: Fertility may be lower the progesterone supplemented programs
Inducing estrus in acyclic (out of season) ewes
Need Progesterone supplementation for a minimum on 5 days (typical is 7 or 10 days)
– CIDR
– MGA
* When Progesterone is removed need to stimulate OVULATION
– eCG
– PG600
CIDR+PG600 out of season synchronization protocol
-10 day CIDR treatment
– 2.5cc PG600 1 day before remove CIDRs
– Estrus ~2 days after CIDR removal
– Can Ram breed or breed timed AI at 48h after CIDR
* (1cc GnRH at time of AI breeding)
Key issues with the out-of-season synchronization protocol
-Antibodies develop to PG600?
– maybe not at low doses; high doses can limit use
Estrus Synchronization in Horses(lights)
-long day breeders
may not cycle til may but need to be bred in feb
-light treatment begins 60-90 days before desired breeding date
Horse estrus synchronization with hormone regulation
-Not common
GNRH
PGF2A-They are really sensitive and can only iuse a small amount
-regumate but used to prevent heat
Abrupt light method(horses)
14.5-16h of light
Gradual light method
increase 1 hour a week
Intermittent light method
-10L-8D-2L-4D
* Photosensitive period (inducible period)
– 1 hour of light 9.5 – 10.5 h after the onset of darkness
Estrus Synchronization in Swine
-not used frequently
-PGF2a not effective til after day 12
-Matrix available
Matrix program in swine
-on feed for 14 days
-85% of gilts fed were in estrus 4-9 days after cessation of feeding (most on day 5)
-could be used to synchronize gilts for entry into breeding herd
-shown to improve farrowing rate
Seminforous tubules
where spermatogenesis occurs
What lines the seminiferous tubules
the basement membrane
What are the Leydig and Sertoli cells analogous to
leydig-theca
sertoli-granulosa cells
Interstital cells-leydig
produce testorone
Sertoli cells
-nuture germ cells through development
-produce numerous steroids
Endocrine regulation of testosterone
-only negative feedback
-increase in testorone means lower GnRH
-only tonic releases
leydig cells endocrine function
-respond to LH
-Produce androsternedione (prepubertal)
-Produces testorone (postpubertal)
sertoli cells endocrine function
-responds to fsh
Produces:
-estrogen
-inhibin
-AMH
-Various Growth Factors
-ABP
What does androgen binding proteins do
binds to testosterone and traps it in the seminiferous tubules to keep testosterone concentration high.
What is the function of estrogen in the male’s testes
stimulates mitosis of the gametes
Spermatogenisis
-onset is during puberty
-hormonal requirements
-lh,fsh and testosterone regulation
-occurs in waves and cycles
Spermatogonal phase
-occurs along the basement membrane
-proliferation,renewal and differentiation
-mitosis
Spermatocyte phase
-meiosis
-diploid to haploid
Spermatid Phase
final maturation steps
round->elongated spermatozoa
Golgi Phase
acrosomic vesicles form
golgi sacules come together and coalesce
Cap phase
acrosomic vesicle spreads over nucleus
Acrosomic phase
-nuclear and cytoplasmic elongation
-centrioles migrate to opposite ends of nucleus
-acrosome wraps around nucleus
-initial formation of the tail
Maturation Phase
-final assembaly and elongation
-acrosome completely wraps around the nucleus
-mitochondria wrap around centrioles in helical fashion.
Acrosome
has enzymes for penetration of the egg
nucleus
-genes for fertilization/syngamy
-genetic variation
mitochondria
energy for motility
flagellum-principle piece
mechanical base for motility
-whiplike motion
Charecteristics of spermatogenesis
-duration is fixed and constant
-stem cells enter spermatogenesis at regular intervals
-stem cells enter spermatogenesis in groups that are connected by intercellular bridges
stage
specific cellular associations
-what is seem at the lumen of the seminfourous tubules
cycle
progression through sequence of all stages along the sertoli cells
Cycle 1
-type A spermatogonia along basement membrane
-entering into the stage of spermatogosis
Cycle 2
intemediate and type b spermatogonia and as a primary spermaroxyte begins meiosis 1
-one later closer to the lumen
Cycle 3
-develops into a secondary spermatocyte
-about halfway to the lumen
-finishes meiosis I
Cycle 4
-finishes meiosis II
-cell undergoes many morphological changes as it develops as a spermatid
-near the lumen
Cycle 4.5
-undergoes final changes
-released into the lumen of the tubule as a spermatozoan
-round -> elongated
Bull spermatogenic cycles
-13.5 days per cycle
-needs 4.5 cycles
-spermatogenesis takes 61 days
Waves
refers to seqquential ordering of stages which occur along the length of the seminiforus tubule
-stage 8 is when it reaches that max
When injury/insult happens to the testicle when is it noticible
it takes a full cycle
semen functions
-fluid environment for transport
-provides energy source
-buffer
-maintains osmolarity
Semen composition
fructose,insitiol,citric acid,prostaglandins, growth factor, cholesterol and lipids
testes contributions to semen
-sperm (immature)
-rete testes fluid
Caput
head of epidiymis
absorption to concentrate sperm
-transport
epdidymis contribution to semen
-maturation of sperm
-loss of cytoplasmic droplet
-gains forward motility
-concentration
-storage
Corpus=body
-secretions mature sperm
-remove cytoplasmic droplet
-foward and progressive motility
-fertility
Cauda=tail
storage for ejaculation
sperm transport through effect ductules
-flow of fluids in the ducts aided by the reabsoprtion of fluids within the ducts
-flow through the ducts aided by cilia
sperm transport through seminiforus tubules
-passively moved by flow of fluids produced by sertoli cells and flowing to rete testis
sperm transport through epidymidis
spontaneous persistaltic contractions of lining the wall
semen evaluation
-volume
-concentration
-sperm motility
-sperm morphology
sperm transport through vas deferens
-flows through vas defefrens due to steady flow through epididymis
-flow through vas deferens at ejaculation due to persitaltic contractions into urethra
-emptying of vas deferens leaves room for further floe from the epididymis
sperm transport through pelvic and penile urethra
-rythmic contractions of bulbospongious and ischoncavernous muscles at ejaculation
-simultaneous emptying of accessory glands to provide fluid vehicle.
what should sperm ph be
around 7 neutral
How is morphology tested
-collect sample
-fix and stain sperm cells
-look at abnormalities
Sperm head abnormalities
pear shape, slender. double head. micro or macro cephalic
Sperm midpiece abnormalities
kinked, double, swollen
Sperm tail abnormalities
coiled, cytoplasmic droplet, absent or double
how is motility tested
-droplet test
-placer fresh sample on slide
-estimate percentage(7/10)
-Ranking System
-high
-medium
-low
What does mate selection rely on
-odors
-visual cues
-vocalizations
Erection Neurological steps
first-erotogenic stimuli cause sensory nerves to fire
second-sensory nerves activate the “reproduction behavior center” in hypothalamus
third-stimulation of parasympathetic nerves that innervate penile arteriole
Fourth-parasympathetic nerve terminals release nitric oxide
Fifth-nitric oxide initiates biochemical cascade that causes an erection
Phase 1 of ejaculation
intromission
Phase 2 of ejaculation
sensory stimulation of glans penis (temperature or pressure0
Phase 3 of ejaculation
sudden and powerful contraction of the urethral, bulbospongiosus, and ischiocavernosus muscles.
Phase 4 of ejaculation
expulsion of sperm
What causes erection
-Sensory stimuli and psychic stimulates the reflex, sympathetic and parasympathetic nerves which causes increased vascular supply
What cause emission
-Sensory stimuli and psychic stimulates the reflex, sympathetic and parasympathetic nerves and causes smooth muscle contractions of accessory glands
What causes ejaculation
-Sensory stimuli and psychic stimulates the reflex, sympathetic and parasympathetic nerves which causes contractions of muscles
Post-copulatory phase
-period of refractory
-time in which additional stimuli will not stimulate male to copulate again
-results in satiation and unwillingness
Site of semon deposition in cattle and sheep
the anterior portion of the vagina
Rapid phase of sperm transport
-occurs within minutes
-peristaltic contractions induced by copulation
-happens upon the time of emission
Slow phase of sperm transport
-fertilizing sperm to AI junction
-8 hours (ewe,cow)
-motility and contractions
Sperm Transport: Cervical Phase
Billions Deposited
Roles
-receptive at estrus
-reservoir cervical crypts
-protection from vagina
-energy from mucus
-filtration of dead and defective sperm.
Sperm Transport: Uterine Phase
Thoudands survive
-longest pathway
-movement-primarily contraction
Sperm Capacitation
-hypermotility
-acrosome reaction
Capacitation
-biochemical change
-alters glycosaminoglycans (prevent acrosome from binding to sona pelusida)
-requires 1-7 hours
-alloes acrosome reaction to occur
Sperm transport uterotubal junction
-limits number of spem reaching oviduct
-acts a second filter
-sperm reservoir
How is the sperm transport affected by the utero-tubal junction
estrogen-allows cells to flow towards oviduct
progesteron-flows towards uterine horn to encourage embryo
Sperm transport-oviduct phase
-only hundreds to thousands survive
Transport by contraction and fluid currents by cillia
-sperm pool in isthmus
Endogenous factors
-age
-sperm maturation
-energy stores
-cell surface
Fate of unsuccessful sperm in cow repro tract
73% recovers
-majority is in mucous discharge
Transport of oocyte
cilia
fluid currents
rhythmic segmented peristaltic contractions
what is the pattern between the time between ovulation and insemination
the longer timr the less fertilization occurs
First Fertilization step
the sperm squeezes through cells left over from the follice
Second fertilization step
the sperms acrosomal enzymes digest jelly coat to penetrate the zona pellucida
third fertilization step
proteins on the sperm head bind to egg receptors
fourth fertilization step
the plama membrane of sperm and egg fuse
Fifth fertilization step
the sperm nucleus enters the egg cytoplasm
sixth fertilization
a feriliziation envelope forms
seventh ferilization
the nuclei of the spperm and egg fuse
Acrosome reaction
-penetration of cumulus granulosa cells and corona radiate
-fusion of plasma membrane and outer acrosomal membrane
-exposure of inner actosomal membrane
-penetration of zonna pellucida
Zona reaction and vitelline block
-initiated by penetrarion of sperm
-release of cortical granules into perivitelline space
-reorganization of zona and vitelline membrane
-enzymes released to harden the zona pellucida
-ZP3 sperm receptors inactivatied
-prevents polyspermy
-efficency decreased by age and temp
Cleavage
mitotic divisions with no increase in cell mass
Blastomeres are equal
-increase in number but not size or shape
Totipotency
capable of producing a complete individual
Morula
compact ball of cells of aproximetly equal size
Blastocyt
cells have rearranged to form compartments
Inner Cell Mass
gives rise to the embryo
Trophectoderm
give rise to the placenta
blastocoele
fluid filled cavity
Hatching of the blastocyst
-removal of the zona pellucida
-allows for expansion and attachment of the blastocyst
Dizygotic
fertilization of 2 ova (non-identical)
Monozygotic
splitting of one ovum
-complete seperation of cells during early cleavage
-formation and latter separation of 2 embryonic vesicles
gastrulation
-blastocyst rearanges
-needs to go from a glob of cells to various layers
Antiluteolytic
porevents or block luteolysis
Luteotropic
stimulates CL to continue to function even in the faceoff PGF
Maternal Recogniation of pregnacy
signal originates from the tropectoderm
-signal acts directly on the endometrium and or ovary
-once signal sent, female will remain in a pregnant state even if conceptus dies
Cow Maternal Recognition of Pregnancy
Recognized on Day: 14-17
Signal: Interferon tau
shift from pgf to pge
Doe Maternal Recognition of Pregnancy
Recognized on Day: 14-17
Signal: Interferon Tau
Shift from PGF to PGE
Ewe Maternal Recognition of Pregnancy
Recognized on Day: 13-16
Signal: Interferon Tau
Shift form PGF to PGE
Sow Maternal Recognition of Pregnancy
Recognized on Day: 10-12
Signal:Estrogen and an increase of blood flow
Horse Maternal Recognition of Pregnancy
Recognized on Day:14-16
Signal:Unsure but know that movement of embryo is needed
