Repro Final Exam Flashcards
1
Q
- A cow first stands to be mounted at 8 am on Monday. The best time to inseminate her is…
A
Monday evening
2
Q
- Fluid-filled follicles visible on the surface of the ovary are described as…
A
Tertiary follicles
3
Q
- Trace the correct path of the sperm from production to ejaculation
A
D) Seminiferous tubules, rete tubules, epididymis, vas deferens, urethra
4
Q
- Which of the following is involved in sperm storage in the male?
A
A) Caudal (tail) epididymis
5
Q
- During spermiogenesis, the correct sequence of developmental stages is…
A
E) Spermatogonia – spermatocytes – spermatids – spermatozoa
6
Q
Going from the outside to the insideof female tract, what is the correct order?
A
E) Vulva, cervix, uterus, oviduct, ovary
7
Q
- Cryptorchids have normal sexual drive (libido) because the…
A
D) Endocrine function is not affected
8
Q
- Sperm mature within the..
A
C) Epididymis
9
Q
- Which of the following species are seasonally polyoestrus?
A
E) Equine, ovine
10
Q
- During the period of the discovery of spermatozoa, who proposed the presence of a preformed individual in sperm – a ‘homunculus’ – as shown below?
A
Hartsoeker
11
Q
- In the 17th and 18th centuries, amongst the theories of ‘generation’, preformationists believed that…
A
B) Organisms develop from miniature versions of themselves already fully formed in the sperm/oocyte
12
Q
- What is the typical sperm concentration of a ram ejaculate?
A
E) 2000-3000 million sperm/ml
13
Q
- The sex of the offspring in mammals is determined by…
A
B) The sperm
14
Q
Vasectomy
A
Libido is unaffected
Seminal vesicles still secrete fluid
The ejaculate does not contain sperm
Bulbourethral glands are not affected by the produce
15
Q
- In cattle, the interval from onset of oestrus to ovulation is approximately…
A
A) 28 hours
16
Q
- The testes..
A
Are the primary reproductive organs in the male
Are essentially non-functional in castrated animals
Produce spermatozoa and testosterone
17
Q
- The main reason why collecting semen using an artificial vagina is preferable to using an electroejaculator is…
A
B) You get a better sample
18
Q
- Which best describes the corpus albicans?
A
D) The regressed corpus luteum
19
Q
- What is the function of the Sertoli cells in the male reproductive tract?
A
E) To support and regulate the cells that produce sperm cells
20
Q
- Which of the following are involved in thermoregulation in the testes?
A
Tunica dartos
Pampiniform plexus
Cremaster muscle
21
Q
- Where on the ovary is progesterone produced?
A
D) In luteal cells
22
Q
- In the absence of pregnancy, prostaglandin F2alpha produced by the ______ brings about _______
A
D) Uterus, luteolysis
23
Q
- According to the data originally generated by Trimberger and Davis (1943), the optimum time for insemination in cattle is..
A
In the middle of oestrus
24
Q
- Secretion of testosterone is controlled by…
A
A) LH from the anterior pituitary
25
27. The final trigger in the cascade that brings about ovulation of the dominant follicle is…
D) LH pulse frequency
26
28. Sperm motility is driven by mitochondria in the…
C) Mid-piece
27
29. Daily sperm production in farm animals is approximately…
A) 15-30 million sperm per gram of testis
28
30. Castration in young male cattle typically involves…
E) Cutting off the blood supply to, or removal of, the testes with a consequent reduction in libido
29
31. LH stimulates the _______ of the testis to produce _______
D) Leydig cells, testosterone
30
32. By placing taffeta trousers on male frogs, who first demonstrated that actual physical contact between the sperm and egg is required for fertilisation?
Spallanzani
31
33. During the oestrous cycle, the term ‘dioestrous’ refers to…
D) The luteal phase, characterised by sustained secretion of progesterone
32
34. Sertoli cells are contained in the…
A) Seminiferous tubules
33
35. Which of the following events occurs in the oviduct in the cow?
E) Oocyte fertilisation
34
36. Sperm and oocytes are similar in which one of the following respects?
D) They have the same number of chromosomes in their nuclei
35
37. The volume of a typical ejaculate in the boar is…
C) 200-250ml
36
38. During each oestrous cycle cows typically have ….
B) 2-3 waves of follicular growth
37
39. Who is credited with the phrase “Ex ovo omnia” (everything comes from the egg)?
E) William Harvey
38
40. Semen deposition during AI is typically in the uterus in the…
A) Cow, mare
39
41. Glycerol is included during semen processing for AI to…
E) Prevent ice crystal formation during cryopreservation
40
42. Spermatogenesis in the bull takes approx….
C) 60 days
41
43. LH is produced by the…
A) Anterior pituitary
42
44. Vasectomised animals make good teaser animals to detect oestrus because….
A) They are excellent at detecting females in oestrous (heat)
B) They have normal levels of testosterone
C) They have normal libido
D) They cannot get females pregnant
43
45. Who is credited with carrying out the first AI in mammals….
A) Ilya Ivanov
44
1. Which of the following is a prostaglandin?
B) Estrumate
45
2. Which of the following list of events occur in the uterus?
E) Blastocyst formation, conceptus elongation, implantation
46
4. An effective oestus synchronisation programme using prostaglandin involves administering two doses…
A) 11 days apart
47
5. The trigger of oocyte maturation in the preovulatory follicle is…
D) The preovulatory surge of LH
48
7. GnRH is used in oestrous synchronisation protocols specifically to….
C) To trigger ovulation
49
8. Insertion of a PRID device on Day 7 after oestrus for 7 days in conjunction with a Prostaglandin injection will …
A) Bring the cow into oestrus within about 2 days of its removal
50
9. The majority of oocytes in follicles on the ovary surface are…
B) Surrounded by compact layers of cumulus cells
51
10. In ruminants, foetal ________ fuse with maternal _______ to form placentomes
E) Cotyledons, caruncles
52
12. Selection of the dominant follicle occurs…
E) During declining FSH concentrations
53
13. The ‘boar effect’ is due to pheromones which…
C) Hasten the onset of puberty
54
Oestrus detection aids
Chin ball harness
Tail paint
Pedometer/ accelerometer
Kamar mount detector
55
15. In terms of the female response to male pheromones, the “ram effect’ in sheep is similar to…
B) The Whitten effect
56
17. The main factor determining whether a dominant follicle ovulates or undergoes atresia…
B) FSH concentration
57
18. The term ‘maternal recognition of pregnancy’ was coined in 1969 by….
D) Roger Short
58
19. Pheromones are known as ‘chemical messengers’. A signalling pheromone typically…
D) Induces an immediate behavioural response in the recipient animal
59
20. Pregnancy can be diagnosed in the cow as early as Day 18 of gestation by….
A) Measuring interferon-stimulated genes (ISGs) in maternal blood leukocytes
60
21. Which of the following species have an endotheliochorial type of placentation involving retention of a single maternal layer
B) Dog, cat
61
22. In which of the following does the conceptus go through a spherical, tubular and filamentous stage prior to implantation?
B) Cattle, sheep, goat, pig
62
23. In terms of oestrous synchronisation, Prostaglandin…
A) Does not work within a very short time from a previous oestrus
B) Does not work in animals without a corpus luteum
C) Causes a decline in circulating progesterone concentration in animals with an active corpus luteum
D) Is ineffective from Day 17 of the cycle onwards
63
24. Placentation in mammals can be classified based on the number of maternal layers retained in the placenta. In ruminants, all three maternal layers are retained and placentation type is called…
C) Epitheliochorial
64
25. Approx. what percentage of a random group of cyclic heifers will respond to a single injection of PGF2alpha?
D) 50-60%
65
26. What is estrumate?
B) A luteolytic agent
66
27. The conceptus-derived substance responsible for maternal recognition of pregnancy in sheep is…
B) Interferon-tau
67
29. In most domestic mammals, the oocyte that is ovulated is at…
B) Metaphase II of meiosis
68
30. In the cow, injecting prostaglandin on Day 2 after oestrous will…
B) Have no effect as the CL is not responsive
69
31. In the cow, the steroid hormones progesterone…
D) Inhibits sexual receptivity
70
32. Implantation in sheep is described as…
B) Cotyledonary
71
33. In double-ovulating cows, where both ovulations occur on the same ovary, transuterine embryo mitigation occurs….
A) Almost never
72
34. Flehmen effect is…
A) Facilitates ability to detect cows in oestrus
B) Does not function in anosmic animals
C) Involves detection of volatile chemicals via the vomernasal organ
D) Involves detection of a signalling pheromone
73
35. The variability in the time to oestrus in cow administered PGF2alpha is due to…
A) The age of dominant follicle
74
36. In the cow, the main mechanism preventing polyspermic fertilisation is…
A) The cervical barrier
B) Receptor down regulation
C) Zona hardening caused by cortical granule exocytosis
D) Vitelline hardening
75
37. Progesterone is used in oestrous synchronisation protocols specifically to…
C) To prevent oestrus and ovulation
76
38. In the cow, which of these events occurs last?
D) Implantation
77
40. In high-producing dairy cows, a major portion of embryonic loss occurs…
Prior to MRP
78
41. In unilateral double-ovulating sheep, transuterine embryo mitigation occurs…
E) Almost always
79
42. Prostaglandins are used in oestrous synchronization protocols specifically to…
E) Cause regression of the CL
80
43. Transuterine embryo mitigation in mice…
B) Does not occur due to the separation of the uterine body and prevaginal portion of the cervix into two canals by a septum
81
44. Injecting a cow with Prostaglandin around Day 5-7 of the oestrous cycle will likely…
A) Have no effect as the animal is undergoing luteolysis
82
45. In pregnancy, going from the foetal to maternal side during pregnancy, the correct order is…
A) Foetus, amnion, allantois, chorion, endometrium
83
47. The so-called ‘Bruce effect’ described by Hilda Bruce in 1959 refers to an effect of pheromones which is manifested as…
A) Pregnancy failure following exposure to strange male
84
48. Cotyledonary placentation occurs in the…
Ruminants
85
49. Which of the following are normally used in Ireland for oestrus synchronisation in sheep?
D) Progestagen sponge
86
Perry
Wrote the first book on Artificial Insemination of Farm Animals in 1945
87
Amantea
Italian credited with designing the first artificial vagina (for semen collection in the dog)
88
Prentice
Head of American Breeders Service (ABS). Credited with developing, in collaboration with Linde, liquid nitrogen containers
89
Ivanov
Established AI in Russia in 1900s cattle and sheep
90
Sorensen
The Dane who established the world's first dairy cooperative in 1936
91
Polge
Discovered the cryprotective properties of glycerol and successfully froze chicken sperm
92
Cassou
Founded the French company IMV in 1963 which supplies much of the equipment and consumables used in AI. Also credited with inventing the plastic straws used for semen
93
Trimberger
Credited with establishing the AM/PM rule for AI (in 1943)
94
Shannon
Credited with developing an extender (Caprogen) which facilitated the use of fresh semen for AI
95
Milovanov
Designed the first artificial vaginas for semen collection in bulls, rams and stallions
96
- In ruminants, the conceptus-derived signal for MRP is
'Interferon-tau'
97
Cotyledons
Structures on the foetal membranes which bind with structures on the endometrium to form placentomes
98
Luteolysis
Regression of the corpus luteum on the ovary under the influence of uterine PGF2alpha
99
Amnion
Membrane that encloses foetus in fluid-filled cavity
100
Epitheliochorial
Classification of placentation in ruminants, pigs and horse based on number of maternal layers retained in the placenta
101
Chorion
The outermost of the foetal membranes which directly contacts the uterine endometrium
102
Hemochorial
Placentation in rodents and primates based on number of maternal layers retained in the placenta
103
Morula
The stage of early embryo development at which the first tight junctions appear between adjacent blastomeres
104
Discoid
Type of placentation in primates
105
Colombo
Italian anatomist and surgeon who coined the term 'placenta'
106
Short
Coined the phrase 'maternal recognition of pregnancy' in 1969
107
As fluid accumulates in the early blastocyst, a cavity known as the __________ is formed
Blastocoele
108
Diffuse
Type of placentation in horses and pigs
109
Cotylendonary
Type of placentation in ruminants
110
Oxytocin
Production of luteolytic pulses of prostaglandin F2alpha is dependent on threshold no. of these receptors that are synthesized by endometrium
111
Zonary
Type of placentation in cats and dogs
112
The maternal recognition of pregnancy signal in primates is said to be _________ because it acts directly on the CL to maintain its function
Luteotrophic
113
Endotheliochorial
Classification of placentation in dogs and cats based on number of maternal layers retained in the placenta
114
In women, the MRP signal is due to production of
hCG
115
The conceptus-derived maternal recognition of pregnancy signal in livestock species is said to be ___________ because it indirectly inhibits the release or production of luteolytic pulses of prostaglandin F2α
Antiluteolytic
116
Caruncles
Structures on the endometrium which bind with structures on the foetal membranes to form placentomes
117
Duplex
The type of uterus found in marsupials and rabbits
118
Inhibin
Produced by ovarian follicles; exerts a negative feedback on FSH secretion
119
Ampulla
Portion of the oviduct nearest the ovary
120
Corpus ________; name given to the newly formed corpus luteum
Hemorrhagicum
121
Progesterone
Hormone produced by the corpus luteum on the ovary responsible for maintenance of pregnancy
122
Prostaglandin
The hormone produced by the uterus responsible for regression of the corpus luteum
123
Corpus ___________; name given to the old regressed corpus luteum
Albicans
124
Isthmus
Portion of the oviduct nearest the uterus
125
Oestradiol
Hormone produced by the ovarian follicles; responsible for sex characteristics in female
Conceptus derived signal for MRP in pigs
The main hormone of the follicular phase of the oestrous cycle
126
Infundibulum
Funnel-shaped structure at the ovarian end of the oviduct which captures the oocyte at ovulation
127
Follicle
Structure on the ovary containing the oocyte
128
Fimbriae
Finger-like processes on the infundibulum which help capture the oocyte at ovulation
129
Bicornuate
The type of uterus found in the cow, ewe and mare
130
Secondary
Type of follicle characterised by proliferation of surrounding granulose cells and the deposition of the zone pellucida
131
Luteolysis
The process of corpus luteum regression
132
Tertiary
Also called astral follicle due to the presence of a fluid-filled antrum
133
Gnrh
Produced by the hypothalamus; stimulates releasing of FSH and LH from Anterior Pituitary
134
Simplex
The type of uterus found in primates including humans
135
Cervix
Site of semen deposition in natural mating and AI in the pig
136
Prophase
The stage of meiosis at which the immature oocyte is arrested in the follicle
137
Capacitation
Term for the physical changes that a sperm undergoes in the female reproductive tract in order to be able to fertilise the oocyte
138
Immature oocytes are at the ___________ stage, characterised by a large roundish nucleus
Germinal Vesicle
139
Uterus
Site of semen deposition in AI in the cow
140
- The progression from Prophase I to Metaphase II of meiosis (which occurs in the follicle in most species) is termed
Oocyte Maturation
141
Hyperactivation
Type of sperm motility characterised by frenzied motion of the flagellum
142
Heparin
A glycosaminoglycan found in high concentrations in the female reproductive tract involved in sperm capacitation
143
ICM (Inner Cell Membrane)
Group of cells in the blastocyst go on to form the foetus
144
Trophoblast
These cells which line the blastocyst go on to form the fetal membranes/placenta
145
Vagina
Site of semen deposition in natural mating in the sheep and cow
146
Metaphase
The stage of meiosis at which the mature oocyte is ovulated in most domestic species and in humans
147
Syngamy
The fusion of the male and female pronucleus at fertilisation
148
Cortical
These granules are located along the periphery of the oocyte membrane and are responsible for blocking polyspermy
149
Zona Pellucida
In most mammals, polyspermy is blocked by hardening of this structure following penetration by a sperm
150
Luteinising Hormone
A preovulatory surge of this hormone approximately 24 h before ovulation is the trigger for oocyte maturation in the follicle
151
Acrosome
A membranous organelle located over the anterior part of the sperm nucleus
152
Hooke
Coined the term 'cell'
153
Aristotle
Described the concepts of oviparity, viviparity, ovoviviparity
154
Fol
Demonstrated that only one sperm is required for fertilisation (in 1876)
155
Steno
Concluded that the ‘testicles’ of woman were analogous to the ovaries of the dogfish
156
Hertwig
Described sperm-egg pronuclear fusion in sea urchin (in 1876)
157
Da Graaf
Described follicle rupture in rabbits. His name is still used in reference to the follicle
158
van Leeuwenhoek
Credited with the discovery of sperm (in 1678)
159
Spallanzani
Demonstrated physical contact between sperm and egg required for fertilisation by putting 'trousers' on frogs
First AI in a dog
160
Preformationism
Belief that organisms develop from miniature versions of themselves already fully formed in the sperm/egg prior to conception
161
Newport
Demonstrated sperm entry into a frog egg in 1854
162
Harvey
Coined the phrase 'ex ova omnia' (everything comes from the egg)
163
Bonnet
Described parthenogenesis in aphids
164
Epigenesis
Belief that organisms arise through a series of stages gradually produced from an undifferentiated mass
165
Von Baer
First to observe and describe a mammalian egg/oocyte
166
Swammardam
Concluded that all animals derive from eggs laid by the same species.
167
Hippocrates
First postulated that generation occurred due to the joint action of two kinds of semen – one from male ejaculate, the other from female menstrual blood
168
Seminiferous Tubules
Site of sperm production in the testes
169
Seminal vesicles
Paired accessory sex glands responsible for the major liquid portion of the final ejaculate
170
Cryptorchidism
Failure of the testes to descend into the scrotum
171
Epididymis
Main function of this organ is sperm maturation
172
Vas deferens
Duct transporting sperm from the tail of the epididymis towards the accessory sex glands
173
Bulbourethral
Also known as Cowper's gland, responsible for producing a preejaculate fluid
174
Pampiniform plexus
A network of small veins acting as a countercurrent heat exchanger, cooling blood in adjacent arteries
175
Tunica dartos
Muscle in scrotum that can increase/decrease the surface area to facilitate evaporative cooling
176
Testosterone
Produced in the testes, main hormone regulating sexual drive (libido) in males
177
Cremaster
Muscle that moves the testes closer to, or further from, the body to aid thermoregulation
178
Rete
The Mediastinum houses these tubules which transport newly formed sperm from the testes to the head of the epididymis
179
Microsmatic
Having a highly developed sense of smell (e.g., the dog)
180
Bruce Effect
involves the tendency for female rodents to terminate their pregnancies following exposure to the scent of an unfamiliar male
181
Lintner
Entomologist who first described the activity of male silkworm moths attracted to a female
182
Butenandt
The German biochemist who first described the chemical structure of the silkworm pheromone (in 1959)
183
Signalling odours
Class of pheromones eliciting an behavioural change in the recipient animal. Typically advertises the sex and breeding condition of broadcaster
184
Flehmen
Behavioural response in male domestic animals in response to pheromones given off by a female in oestrus
185
Priming odours
Class of pheromones eliciting indirect modifying influence on internal physiological processes of other individuals
186
Whitten Effect
involves synchronisation of the oestrous cycles of a group of females when a male or his pheromone is introduced (similar to the 'Ram Effect')
187
- Bombykol
A pheromone released by the female silkworm moth to attract mates
188
- Vomernasal
Also called Jacobson’s organ. Involved in odour perception for social communication
189
'Vandenbergh Effect'
refers to the acceleration of the onset of puberty due to the presence of an unrelated male (similar to the 'Boar Effect')
190
Progesterone
The main hormone of the luteal phase of the oestrous cycle
191
Theca
Follicular cells that form Small Luteal Cells after ovulation
192
Metoestrus
The immediate post-ovulation period (from approximately Day 1 to Day 4)
193
Polyestrous
Having successive oestrous cycles throughout the year/breeding season (e.g., cow, ewe, mare)
194
Atresia
The ultimate fate of most follicles on the ovary
195
Granulosa
Follicular cells that form Large Luteal Cells after ovulation
196
Dioestrus
Period of the oestrous cycle from approximately Day 5 to Day 18 corresponding to the luteal phase
197
Monoestrus
Having a single oestrus event during a breeding season (e.g., dog, bear)
198
Oestrus
The period of sexual receptivity in the cow
199
Spermiogenesis
The third and final stage of spermatogenesis
The process of differentiation of undifferentiated spermatid to a fully differentiated spermatozoon
200
Casa
Commonly used abbreviation for a computerised method for the analysis of sperm motility
201
Leydig
Cells present in the testicular interstitial tissue, whose main function is to produce testosterone.
202
AV
Abbreviation for the device used for semen collection in the bull, ram and stallion
Artificial Vagina
203
Spermatogonium
An undifferentiated male germ cell. Will eventually form a spermatozoon
204
Luteinising
Testosterone production in testicular Leydig cells is controlled by this hormone
205
Hypothalamus
The part of the brain that secretes Gonadotropin-releasing hormone (GnRH)
206
Spermatocytogenesis
The process of cell division during spermatogenesis
207
Electroejaculation
A method of semen collection used for prepubertal animals or when an animal cannot be trained to use an artificial vagina
208
Follicle Stimulating Hormone (FSH)
Through its action on Sertoli cells, spermatogenesis is controlled by this hormone
209
Sertoli
Also known as sustentacular cells and located in the seminiferous tubules in the testes, these cells provide physical, nutritional, and regulatory support for developing sperm cells.
210
Gonadotropin
Collective term for a hormone that stimulates either the ovaries, testes or both.
211
Meiosis
The second of the 3 stages of spermatogenesis, lasting 23 days in the bull and resulting in haploid spermatids
212
Proliferation
The first of the 3 stages of spermatogenesis, lasting 21 days in the bull
213
Compensable
Deleterious sperm traits that can typically be overcome by increasing sperm number
214
Haemocytometer
Used to count cells, including sperm cells during semen assessment
215
PAGs
Pregnancy-associated glycoproteins
Show up in pregnant and early pp cows
216
Standing Heat Duration
9hrs average, 3-30hrs
217
How many follicular waves in a cycle?
2-3, 7-10 days each
218
Fate of dominant follicle (DF) depends on
LH pulse frequency
219
1 LH pulse/hour is...
Ovulation (follicular phase)
220
1 LH pulse/4-6hours is...
Atresia (luteal phase)
221
PRID
Progesterone Releasing Intravaginal Device
Contains progesterone
222
CIDR
Controlled Internal Drug Release
Contains progesterone
223
Use of progestogens
Maintain the cow under the influence of progesterone until CL regresses.
On removal, animal responds to decreasing P4 with oestrus 2-5 days later
224
If you administer a random group of heifers a single injection of PG what % will respond?
60%
225
Prostaglandin injected how often?
2 injections 11 days apart
Inseminate after second inj.
226
Injection of prostaglandin effects:
Day 0-4
Day 5-16
Day 16-21
After 2nd injection
Day 0-4 no effect
Day 5-16 oestrus in 2-4 days
Day 16-21 oestrus naturally in 1-5 days
After 2nd inj. oestrus in 2-4 days
Time to response depends on follicular wave
227
Ovsynch injection protocol
GnRH - start new follicle wave (P4)
Prostaglandin - Regress CL
GnRH - Ovulate follicle (P4)
AI
228
Co-synch
GnRH and AI given at same time
Fertility lower but more advantages
229
PMSG
Pregnant Mare Serum Gonadotropin
230
eCG
Equine Chorionic Gonadotropin
231
Sheep synchronisation
Give PMSG/eCG 1-2 days before withdrawal of sponge
Rams in 48hrs after sponge out
232
Sow synchronisation
PGF2a - won't regress CL until day 12 of cycle
Progestins - MGA(melengestrol acetate) will sync oestrus but cause cysts
- Regumate (20mg/day for 18days) oestrus 4-8 days after
18days
Wean piglets - oestrus 3-6 days after
233
Mare synchronisation
Lutalyse - mare CL more sensitive than cows, side effects more severe
Regumate - feed for 12-14 days, on last day give PGF2a, in heat 3-4 days after but ovulates day 8
234
Monozygous/Monozygotic twins
Fertilisation of 1 oocyte that cleaves and forms 2 embryos
Genotypically & phenotypically identical - same sex
235
Dizygous/Dizygotic twins
Fertilisation of 2 oocytes during the same oestrous cycle
Same/opposite sex
236
Dual-breed twins
Same dam, different sires
Heteropaternal
237
Superfetation
Twins born 2 weeks apart
238
Sex Determination (Gonadal Sex Determination)
Decision within the early gonad to form a testis or an ovary
3 step process
239
SRY
Sex-determining region Y
Responsible for the initiation of male sex determination
240
Testicular hormones imposed on foetus to give male characteristics
Testosterone
Anti-Mullerian hormone (AMH)
241
Absence or inactivity or testosterone and AMH will result in foetus being..
Female
242
Freemartin
Ovaries are stunted & depleted of germ cells
May contain seminiferous tubules
Have high concentrations of AMH
243
Anastomosis
Cross-connection between adjacent channels or tubes
>90% occurrence in natural twins in cattle
244
Gestation duration
Cow
Ewe
Sow
Mare
Cow 284
Ewe 147
Sow 114
Mare 335
245
3 stages of parturition
Dilation and initiation of myometrial contractions (myo --> muscle)
Expulsion of foetus
Expulsion of foetal membranes
246
Hormone changes in parturition
P4 decrease
E2 increase
PG increase
247
Induction of parturition in cattle
Injection of a synthetic glucocorticoid (dexamethasone) - takes 2-3 days
Using PG - parturition within 1-8 days
248
Oocyte recovery
Follicle aspiration
Allow settle
Searching
Oocyte recovery
249
3 stages of Embryo Production
In vitro maturation (IVM)
In vitro fertilisation (IVF)
In vitro Culture (IVC)
250
Homotransfer
Cow to cow
251
Heterotransfer
Cow to sheep
252
MOET 4 steps
Synchronisation of donors/recipients
Superovulation/AI of donors
Embryo Recovery from donors
Embryo Transfer to recipients
253
Intracytoplasmic sperm injection (ICSI)
1 sperm (sexing semen)
254
Nuclear Transfer (NT)
Transfer of a diploid nucleus into a chromosome free oocyte to produce a reconstituted embryo
255
Steps in Nuclear Transfer (NT)
Enucleation of matured oocyte
Transfer of donor nucleus
Fusion using a DC electrical pulse
256
Gene Editing
ZFNs
TALENs
CRISPR-Cas System
ZFNs - Zinc finger nucleases
TALENs - Transcription Activator-Like Effector-based Nucleases
CRISPR-Cas System - Clustered regularly interspaced short palindromic repeats
257
Spermatogonial Stem Cell Transplantation
Creation of males lacking their own germline cells, but have spermatogonial stem cells from a donor male
258
Embryonic Diapase
'Delayed implantation'
Period in early development during which an embryo remains suspended at the blastocyst stage
259
Facultative diapause
Induced by physiological conditions
260
Obligate Diapause
Present in every gestation
261
(Poultry) Oviduct 5 sections (order of ovary end to shell gland)
Infundibulum
Magnum
Isthmus
Uterus
Vagina
262
Infundibulum (poultry)
Pick up ovulated ova
Site of fertilisation
15-30mins
263
Magnum (poultry)
Secretion of albumin (egg white)
2-3 hours
264
Isthmus (poultry)
Secretion of shell membranes (primarily ovokeratin)
1.5hrs
265
Shell gland/Uterus (poultry)
Fluid is added to albumin
Shell production
18-20 hours
266
Vagina (poultry)
Adds nothing to egg
Egg transport, sperm deposition and storage
1 min
267
Targets for optimum fertility
Pregnant to 1st service
6 wk in calf rate
12 wk in calf rate
Pregnant to 1st service - 55-60%
6 wk in calf rate - 70%
12 wk in calf rate - >90%
268
Involution
Period where cow can't become pregnant
269
Causes of Embryonic Loss
Ovulation of incompetent oocyte
Retarded embryo development giving poor MRP signal
Inadequate P4 rise after AI
Detrimental uterine environment
Metabolic/nutrient mobilisation
270
Pregnancy loss D20-30 in 25% cows becuase of...
50% CL regression - P4 decrease, PAGs constant
50% embryo death - PAGs decrease, P4 constant
