Repro Mcq 1

Front 1

Anovulatory Anoestrus decrease is GnRH possible causes

Back 1

Suckling offspring; Poor body condition score; off season

Front 2

GnRH causes

Back 2

Transitory (due to short half life) release of LH and some FSH

Front 3

GnRH is a

Back 3

Neauropeptide 10 amino acids in length

Front 4

GnRH is released by

Back 4

Hypothalamus

Front 5

LH and FSH is released by

Back 5

Anterior Pituitary

Front 6

LH (in females) causes

Back 6

Final maturation and ovulation of the dominant follicle;

Binds to theca & produces androgen

Front 7

FSH (in females) causes

Back 7

Waves of folicular development;

Binds to granulosa & stimulates aromatase

Front 8

GnRH and LH patterns

Back 8

Luteal Phase: High amplitude, low frequency

Folicular Phase: Low amplitude, high frequency

Front 9

LH and FSH are release where by what?

Back 9

Anterior pituitary from gonadotroph cells

Front 10

LH and FSH are classified as

Back 10

Gonadotrophins which are glycoproteins with alpha and beta subunits

Front 11

What part of LH, FSH, and TSH structure is the same

Back 11

Alpha subunits

Front 12

Half life of LH

Back 12

0.5 - 3 hrs

Front 13

Half Life of FSH

Back 13

3 - 5 hrs

Front 14

External Factors

Back 14

Day length; temperature; food; pheromones from either sex; suckling stimulus; mating

Front 15

Internal Factors

Back 15

Body metabolism; fat; steroid hormones (oestrogen and progesterone) in blood; other neural pathways in hypothalamus

Front 16

McClinton effect

Back 16

Cycles become synced between females housed together for extended periods

Front 17

Ram effect

Back 17

Presence of ram will cause an increase in LH pulse frequency

Front 18

Suckling stimulus

Back 18

Nursing can decrease likelihood of pregnancy; extremely strong in pigs

Front 19

More melatonin is released with

Back 19

Shorter days

Front 20

Other neural pathways affecting GnRH production

Back 20

Catecholaminergic, serotonergic, etc.

Front 21

Neurotrasnmitters affecting GnRH production

Back 21

Dopamine, norepinephrine, epinephrine, serotonin, opioids, etc.

Front 22

Alternative affectors of FSH release

Back 22

Inhibin, activin, and oestradiol

Front 23

LH is released

Back 23

In packets after accumulation in the anterior pituitary

Front 24

FSH is released

Back 24

predominantly directly after synthesis

Front 25

Progesterone feedback

Back 25

Negative feedback on GnRH pulse frequency and thus LH pulse frequency

Front 26

Estrogen (in P4 presence) and inhibin (produced by DF) feedback

Back 26

Negative feedback on FSH production and selection of a dominant follicle

Front 27

Progesterone (in female) produced by

Back 27

Corpus luteum, and placenta

Front 28

Key hormone regulating length of luteal phase

Back 28

Progesterone

Front 29

Estrogen (in female) produced by

Back 29

Follicle and placenta

Front 30

Estrogen (in male) is produced by

Back 30

Sertoli cells with aromatase

Front 31

Testosterone (in males) is produced by

Back 31

Leydig cells

Front 32

Testosterone (in males) have a negative feedback effect on

Back 32

LH and FSH (in males)

Front 33

Inhibin (in males) produced by

Back 33

Sertoli cells

Front 34

Inhibin (in females) is produced by

Back 34

Granulosa cells from both medium, large, and atretic follicles

Front 35

Activin (in females) has a positive feedback

Back 35

Release of FSH from the anterior pituitary

Front 36

Estrogen has a positive feedback effect unique to

Back 36

Females in the follicular phase

Front 37

Estrogen (females) has a positive feedback (only in the follicular phase) on

Back 37

GnRH pulse frequency

Front 38

Estrogen positive feedback has what final result

Back 38

LH/FSH surge resulting in ovulation

Front 39

Estrogen has a positive effect on what and where

Back 39

GnRH receptors on gonadotrophs

Front 40

Half life of hCG

Back 40

12-18 hours

Front 41

hCG has similar effects to

Back 41

LH and binds to LH receptors

Front 42

hCG is produced during

Back 42

Pregnancy

Front 43

eCG (in horses) has similar effects to

Back 43

LH (ovulation of mare follicles)

Front 44

eCG (not in horses) has similar effects to

Back 44

FSH with some very minor LH activity

Front 45

hMG (human menopausal gonadorephin) has similar effects to

Back 45

FSH with some LH activity in women

Front 46

Oestrus is

Back 46

Time of heat behavior/ period of sexual receptivity

Front 47

Oestrous is

Back 47

Heat behavior itself of the entirety of the reproductive cycle in females

Front 48

Duration of oestrus in cows

Back 48

8 hrs (1 - 24 hr range)

Front 49

Time of gonadotropin surge in cows, ewes, and sows

Back 49

At the onset of oestrus

Front 50

Time of ovulation in cows

Back 50

10 - 14 hrs after oestrus

Front 51

Duration of oestrus in ewes

Back 51

36 hrs

Front 52

Time of ovulation in ewes

Back 52

24 - 30 hrs after the onset of oestrus

Front 53

Cycle Length in cows and mares

Back 53

18 - 24 days

Front 54

Cycle length in ewes

Back 54

15 - 17 days

Front 55

Duration of oestrus in sows

Back 55

2 - 3 days

Front 56

Time of ovulation in sows

Back 56

36 - 48 hrs after onset of oestrus

Front 57

Cycle length of sows

Back 57

19 - 22 days

Front 58

Duration of oestrus in mares

Back 58

5 - 15+ days

Front 59

Time of gonadotropin surge in mares

Back 59

Gradual rise during oestrus

Front 60

Time of ovulation in mares

Back 60

1 - 2 days before the end of oestrus

Front 61

Heifers/Cows show signs of oestrus through

Back 61

Expression of mounting behavior and standing to be mounted by males and females

Front 62

Silent Heat

Back 62

Ovulation without external manifestation of behavioral signs

Sheep and Cattle can experience this at their first ever ovulation or the first after parturition

Front 63

Split Heat

Back 63

Interruption in sexual receptivity

Occurs during transitions between breeding and non-breeding seasons

Mares - may have day long breaks in heats

Cows - may have hour long breaks in heat

Front 64

Foal Heat

Back 64

First heat approximately 7 days after foaling

Front 65

Prolonged oestrus

Back 65

Long lasting heat in mares during the transition into the breeding season

Front 66

Pregnancy heat

Back 66

Some animals can have behavioral oestrus during pregnancy

Ewes, cows, lab animals

Front 67

Superfoetation

Back 67

Two parturitions due to fertilization during pregnancy heats

Can occur in rats, mice, rabbits

Front 68

Nymphomania

Back 68

Continuous desire to mate caused by cystic ovaries releasing hormones that continue to cause heat behavior

Front 69

Animals that have spontaneous ovulation and cyclical CL formation / regression

Back 69

Ewe, cow, sow, goat, mare, primates

Front 70

Animals that have spontaneous ovulation with CL lasting entire pregnancy

Back 70

Bitch

Front 71

Animals that have spontaneous ovulation but require mating for CL formation

Back 71

Rat

Front 72

Animals that are induced ovulators requiring mating for both ovulation and CL formation

Back 72

Rabbit, ferret, mink, camel, llama, cat

Front 73

Factors that cause ovulation in induced ovulators

Back 73

Vaginal distention

Ovulation inducing factor found within seminal plasma

Front 74

Ovulation Inducing Factor causes

Back 74

LH surge in both induced ovulating and spontaneous ovulating species

Front 75

Metoestrus

Back 75

Time of corpus luteum formation and rising progesterone

Front 76

Dioestrus

Back 76

Time when CL is present and progesterone is high

Front 77

Pro-oestrus

Back 77

Time when CL degresses, progesteron is low, estrogen is high

Front 78

Luteal phase consists of

Back 78

Metoestrus and dioestrous

Front 79

Follicular phase consists of

Back 79

Pro-oestrus and oestrus

Front 80

Ovarian changes can be detected by

Back 80

Visual exam of vagina and cervix

Rectal palpation

Ultrasound scanning

Hormone assay (progesterone)

Front 81

Speculum used in oestrus detection

Back 81

Wall around cervix and vagina redder

Clear mucus production from the cervix

Front 82

Rectal palpation in oestrus detection

Back 82

Tone of the uterus

Cows: uterus tones up

Mares: uterus becomes flacid

Front 83

Ultrasound in oestrus detection

Back 83

Can visualize mucus and structures of the ovaries (follicle, CL)

Front 84

Hormonal assays in oestrus detection

Back 84

Progesterone is produced in the CL and can be measured in milk

Front 85

LH induces

Back 85

Ovulation; resumption of meiosis; stimulates progesterone production from CL

Front 86

Oestrogen induced changes to the female reproductive tract

Back 86

Increased motility, secretory activity, and tract blood flow; relaxation of the cervix

Front 87

Progesterone effect in pregnancy

Back 87

Decreased myometrial contractions of the uterus;

Increased protein secretions in uterus;

Cervical closure and decreased mucus

Front 88

Prolactin is produced by

Back 88

Anterior Pituitary (Not LH or FSH flashcard)

Front 89

PGF2Alpha causes

Back 89

Regression of the CL at the end of the luteal phase

Front 90

How many follicular waves in the mare

Back 90

One; 25% have two

Front 91

How many follicular waves in the cow

Back 91

Three about every 7 days

Front 92

How many follicular waves in induced ovulators

Back 92

Variable depending on frequency of matings

Front 93

Role of follicle

Back 93

Released ovum;

Produces steroids;

Forms CL after ovulation

Front 94

Oogonia initiates

Back 94

Meiosis 1

Front 95

Primary oocyte arrested at

Back 95

Diplotene stage of meiosis 1 resumes are ovulation

Front 96

Oogenesis

Back 96

Formation and replication of eggs from primordial germ cells early in fetal life; initially multiply by mitosis

Front 97

Primary follicle

Back 97

Resting stage; still haploid

Front 98

Proliferating primary

Back 98

Increase in size of oocyte

Front 99

Secondary follicles

Back 99

Multiple layers of follicular cells; granulosa layer; theca layer

Front 100

Tertiary follicle

Back 100

Follicle forms a fluid filled cavity (antrum);

Differentiation of cell layers in follicle wall;

Become responsive to gonadotrophins

Front 101

Granulosa Cells

Back 101

Surround the oocyte and help in ovum transport in the oviduct after ovulation;

Convert testosterone to estrogen

Front 102

Theca Externa

Back 102

Line the outside later of the follicle wall;

Composed of connective tissue and blood vessels

Front 103

Theca Interna

Back 103

Middle layer of cells of the follicle wall;

Produces testosterone which is converted to estrogen by the granulosa cells

Front 104

Two cell theory

Back 104

Theca interna produces testosterone;

Granulosa cells produce estrogen from the testosterone

Front 105

Follicle development phases

Back 105

Increased FSH - Causes formation of a follicular cohort;

Decreased FSH - Selects a dominant follicle(s);

LH Dependant dominance with low FSH preventing further follicular development;

Dependant upon LH pulse frequency

Front 106

Fate of a follicle

Back 106

Either is ovulated or goes through atresia

Front 107

LH pulse frequency for ovulation

Back 107

1 pulse per hour

Front 108

LH pulse frequency for atresia

Back 108

1 pulse per 2 - 4 hours

Front 109

After ovulation LH binds to

Back 109

Luteal cells and promotes the production of progesterone

Front 110

IGFs effects

Back 110

Stimulate granulosa cell proliferation;

Sensitization of granulosa cells to FSH;

Play a key role in selection of dominant follicles;

Important in follicle survival

Front 111

IGF-BPs

Back 111

Bind to IGF and removes them from the equation;

Less found in follicles which survive, more in the one that dies

Front 112

Dictytate nucleus and germinal vesicle stage (GV stage)

Back 112

The stage at which the primary oocyte gets arrested at the diplotene stage of meiosis 1

Front 113

Resumption of meiosis due to

Back 113

Surge in gonadotrophins and then at fertilization

Front 114

Secondary meiosis arrest occurs at

Back 114

Metaphase II in the secondary oocyte

Front 115

Granulosa cells, even before ovulation, begin to cause

Back 115

Luteinization of pre-ovulatory follicle

Front 116

How many follicular waves in the ewe

Back 116

3 - 4

Front 117

How many waves in the sows and humans

Back 117

2 (32% of humans have 3)

Front 118

Number of ovulated follicles in the cow

Back 118

1 follicle

Front 119

Number of ovulated follicles in the ewe

Back 119

1 - 5 follicles

Front 120

Number of ovulated follicles in the sow

Back 120

10 - 20 follicles

Front 121

Number of ovulated follicles in the mare

Back 121

1 - 2 follicles

Front 122

Number of ovulated follicles in the bitch

Back 122

2 - 10 follicles

Front 123

Number of ovulated follicles in the queen

Back 123

2 - 8 follicles

Front 124

Cystic follicular development

Back 124

Failure of the dominant follicle to ovulate;

May become up to golf ball in size (30 - 40mm);

Secretes estrodiol and may effect behavior such as nymphomania;

Can cause anoestrus and long post-partum period

Front 125

Luteal cyst vs follicular cyst

Back 125

Whether luteal tissue is present or not

Front 126

Luteotrophin

Back 126

Maintains corpus luteum

Front 127

Lyteolysin

Back 127

Causes corpus luteum to regress (bitch is an exception)

Front 128

Amount of progesterone released from corpus luteum is correlated to

Back 128

The size of the corpus luteum

Front 129

PGF2Alpha is produced by

Back 129

The endometrium of the uturus

Front 130

Oxytocin binding at the beginning of the cycle triggers the release of

Back 130

PGF2Alpha and regressions of the CL with 24-36 hrs

Front 131

hCG in humans is luteotrophic which means it

Back 131

Helps corpus luteum to survive;

Stimulates corpus luteum and progesterone production;

Protects against luteolysis

Front 132

PGF2Alpha can be absorbed through the skin and cause

Back 132

Abortion in females and issues with asthma for both males and females

Front 133

Oxytocin receptors are induced by

Back 133

The presence of estrogen

Front 134

PGF2Alpha is released into the

Back 134

Uterine vein

Front 135

PGF2Alpha is picked up by the ovarian artery by

Back 135

Counter-current exchange with the uterine vein

Front 136

Corpus Luteum helps fully regress by synthesizing

Back 136

Oxytocin (it is not only synthesized by the posterior pituitary)

Front 137

Corpus albicans can be seen for

Back 137

Multiple cycles past its formation as small orange blip

Front 138

Maintenance of corpus luteum during pregnancy is by

Back 138

Chorionic gonadotrphins - primates;

Interferon Tau - Ruminants

Front 139

Produced by embryo to help maintain pregnancy

Back 139

Luteotrophins

Front 140

Prostoglandin E series have effects that are

Back 140

Opposite to the effects of Prostoglandin F series

Front 141

Maternal recognition of pregnancy in sow

Back 141

Requires at least 2 embryos per horn;

Occurs at elongation at days 11 - 12;

Embryo converts Progesterone to oestrone S04 and then to E2;

Prevents uptake of PGF2Alpha uptake into uterine vein, it just build up in the uterus;

Front 142

Maternal recognition of pregnancy in mares: Stage 1

Back 142

Embryo patrols uterus until day 16 when implantation occurs;

Patroling somehow prevents the release of PGF2Alpha

Front 143

Maternal recognition of pregnancy in mares: Stage 2

Back 143

Endometrial cups produce eCG which causes luteinization of additional follicles leading to accessory corpus luteums;

Accessory CLs produce additional progesterone

Front 144

Corpus luteum and accessory corpus luteums regress after which day in mares

Back 144

120 - 180 days

Front 145

mRNA expression for interferon tau is initiated by

Back 145

Blastocyst elongation;

Decreases after implantation

Front 146

Other luteotrophins

Back 146

Uterine infection (can block prostogladin production;

eCG in mares;

Causes of luteal cysts

Front 147

How can you monitor luteal funtion

Back 147

Rectal exam;

Levels of progesterone in milk or blood;

Ultrasound scanning of ovaries

Front 148

Fertilization occurs at

Back 148

Ampullary - isthmus junction

Front 149

Oocyte gains

Back 149

Sperm receptor proteins;

Increased intracellular Ca stores;

Synthesis and storage of mRNAs and proteins;

Polyspermy blocks

Front 150

Embryo attains totipotency

Back 150

Any one of the cells is capable of generating an individual

Front 151

Morula

Back 151

Still capable of viewing individual cells; then the start of compaction occurs

Front 152

Blastocyst

Back 152

Formation of different layers of cells;

presence of a cavity (blastocoel);

later hatching out of the zona pelucida;

Elongation of embryo occurs in most species (not in human or horse)

Front 153

Maintaining of the cyclical shape in mares is do to

Back 153

Glycocalyx structure

Front 154

Fertilization and initial cleavages of embryo occur in

Back 154

The oviduct

Front 155

Progesterone aides the ovum by

Back 155

Relaxing the UTJ allowing entry to the uterus

Front 156

Oestrogen at low doses in the oviduct

Back 156

Increases ovum transport

Front 157

Oestrogen at high doses in the oviduct

Back 157

Stops transport

Front 158

Functions of the uterus

Back 158

Nutrition; differentiation; implantation; and support of pregnancy

Front 159

Regulation of embryo and edometrium (uterine) development

Back 159

Both systemically (ovarian steroids) and locally (uterine and embryonic secretions)

Front 160

Synchrony between embryo and endometrium

Back 160

Can differ by:

+/- 1 day in cows;

+/- 2 days in ewes

Very precise in pigs

Front 161

In order to maintain pregnancy uterus requires

Back 161

Priming with estrogen and progesterone in previous cycle;

and progesterone rise 4 - 8 days after AI;

Front 162

Transuterine migration in sows

Back 162

Allows for embryo spacing to occur

Front 163

Early embryo loss (failure of maternal recognition)

Back 163

20 - 40% loss

Front 164

Fertilization failure

Back 164

5 - 10% loss

Front 165

Embryo development stimulated by

Back 165

Growth hormone, insulin, and IGF1 from maternal circulation;

IGF2 produced by embryo

Front 166

Production of Interferon-tau by

Back 166

Trophoblast cells; only embryo cell required for maternal recognition

Front 167

Role of placenta

Back 167

Nourishment of young; mechanical protection; selective permiability (no bacteria)

Front 168

Delayed implantation

Back 168

Occurs in some species (marsupials, mink, etc.);

Blastocyst development arrested until more favorable conditions

Front 169

Majority (66%) of fetal growth in

Back 169

The last trimester of pregnancy

Front 170

Progesterone important over the entire pregnancy for

Back 170

Stimulate embryo development;

Suppress myometrial contractions;

Acts on mammary gland;

Can be of ovarian and/or embryo in origin depending on species`

Front 171

Ovaries required for the entire pregnancy in

Back 171

Cow (still producing 80% of progesterone after day 200);

Sow; goat; rodents; bitch; rabbit

Front 172

Relaxin is produced by

Back 172

Ovary (mainly CL) and placenta

Front 173

Effect of relaxin

Back 173

Relaxation and softening of pelvic ligament;

Cervical softening;

Levels increase last trimester with spike 2 - 3 days before parturition with a boost from estrogen

Front 174

Initiation of parturition in non-primates/mares

Back 174

Fetal anterior pituitary - adrenal axis;

Increase in fetal stress --> increase in fetal ACTH & then cortisol --> converting placental progesterone to estrogen --> increase tract secretions & contraction --> increased fetal stress;

Fetal cortisol --> increases prostoglandin --> causes luteolysis and increases relaxin

Front 175

Withdrawal of progesterone by parturition causes

Back 175

Myometrial contractions

Front 176

Increase in estrogen near parturition causes

Back 176

Stimulates myometrium;

Stimulates PGF release;

Stimulates uterine contractility (in absence of P4)

Front 177

Prostaglandin F2Alpha near parturition

Back 177

Synthesis stimulated by rise in E2 and oxytocin receptor induction;

Is luteolytic (goat, cow and sow);

Stimulates myometrium

Front 178

Oxytocin near parturition

Back 178

Is required during expulsion of fetus;

Stimulates strong uterine contractions;

Release induced by vaginal distension

Front 179

Relaxin is produced by

Back 179

Ovary at parturition

Front 180

Hormones at mare parturition differ by

Back 180

Progesterone remaining high; esterogen stays low; stimulation of fetal adrenals;

Works by being very sensitive to oxytocin

Front 181

Three stages of labour

Back 181

1) Dilation of cervix - relaxing and E2;

2) Expulsion of fetus - E2, PGF2Alpha, and oxytocin;

3) Expulsion of placenta - oxytocin and PGF2Alpha

Front 182

Length of gestation in mares

Back 182

11 months

Front 183

Length of gestation in Cows

Back 183

283 days

Front 184

Length of gestation in ewes

Back 184

145 days

Front 185

Length of gestation in sow

Back 185

112 - 114 days

Front 186

Retained placenta is toxic in

Back 186

Horses (retained placenta)

Front 187

Retained placenta is not toxic but increases likelihood of infection in

Back 187

Cows and sheep (retained placenta)

Front 188

Hours for expulsion of fetus in mares

Back 188

0.2 - 0.5 hr

Front 189

Hours for expulsion of fetus in cows

Back 189

0.5 - 1.0 hr

Front 190

Hours for expulsion of fetus in ewes

Back 190

0.5 - 2.0 hr

Front 191

Hours for expulsion of fetus in sows

Back 191

2.5 - 3.0 hr

Front 192

Hours for expulsion of placenta in mares

Back 192

1 hr

Front 193

Hours for expulsion of placenta in cows

Back 193

4 - 5 hrs; up to 12 hrs

Front 194

Hours for expulsion of placenta in ewes

Back 194

0.5 - 8 hrs

Front 195

Hours for expulsion of placenta in sows

Back 195

1 - 4 hrs

Front 196

Control of parturition if source of P4 is CL

Back 196

Use PGF2Alpha to induce parturition

Front 197

Control of parturition if source of P4 is placenta

Back 197

Use cortisol derivative to induce parturition

Front 198

Potential side effects of inducing parturition

Back 198

May increase mortality of newborn and possibly dam;

May have retained placenta

Front 199

Involution

Back 199

Return of the uterus back to normal after parturition

Front 200

Involution in cattle takes

Back 200

40 - 50 days to complete;

Physical (actual uterine structure): day 0 -30;

Physiological (lower pregnancy rates): day 30 - 50

Front 201

Factors that delay involution

Back 201

Uterine infection (most cows develope infection but they clear up in 20 - 30 days);

Retained placenta;

Induction of parturition

Front 202

Involution in ewes takes

Back 202

15 - 25 days; Large amounts of cellular debris

Front 203

Involution in sows takes

Back 203

25 - 30 days

Front 204

Involution in mares

Back 204

15 - 25 days

Very rapid; uterus normal size by first heat; endometrial recovery is slower (causes problems if become pregnant in foal heat)

Front 205

Key requirements for re-breeding an animal

Back 205

Normal uterine involution; Early resumption of cyclicity; High efficiency of oestrous detection; High conception rate per service

Front 206

Considered a retained placenta in cows if it takes

Back 206

Longer than 12 hours to be expelled

Front 207

Endometritis/ Metritis is

Back 207

Inflammation of uterus which decreases conception rate;

High pathogen load low immunity;

Most common in early port-partum period;

Cows with more PGF2Alpha more susceptable

Front 208

Pyometra is

Back 208

Most common type;

Bacteria in the uterus proliferate after 1st ovulation;

Progesterone down regulates the immune system;

Blocks prostoglandin release leading to retained placenta;

Front 209

Resumption of ovarian activity in cattle

Back 209

3-5 days after calving: FSH rise (suppressed by high steroids at late pregnancy);

75% of dairy cattle ovulate first dominant follicle; usually a silent heat;

25% of beef cattle ovulate first dominant follicle

Front 210

Puberty in females

Back 210

The time at which they begin to express heat and stand to be mounted

Front 211

Puberty in males

Back 211

The age at which the male can produce sufficient sperm for successful fertilization

Front 212

Prior to puberty in females

Back 212

FSH waves are present after birth;

Strong negative feedback of estrogen on GnRH and this LH which keeps pulse frequency low and prevents any dominant follicle from being ovulated;

Front 213

Onset of puberty

Back 213

Increase in size of dominant follicles and estrogen concentrations;

Get positive feedback and first ovulation

In ruminants: silent ovulation and short cycle and prior priming of brain with P4

Front 214

Onset of puberty in ewes

Back 214

40+ kgs at 25 to 35 weeks

Front 215

Onset of puberty in heifers

Back 215

200 - 250 kg at 8 - 12 months

Front 216

Onset of puberty in Gilts

Back 216

90 - 100 kg at 150 - 170 days

Front 217

Onset of puberty in filly

Back 217

12 - 18 months of age

Front 218

Onset of puberty in bulls

Back 218

9 - 12 months of age

Front 219

Key events of puberty in bulls

Back 219

Testes descend to scrotum at birth;

Testicular tissue differentiates at 3 - 4 months;

Steroids produced by 4 months;

Mature sperm appearing by 6 months;

Sperm capable of fertilization at 8 - 10 months;

Good sperm quality by 15 - 16 months

Front 220

Male puberty developments

Back 220

Development of secondary sex characteristics;

Increased size of penis;

Progressive detachment of sheath to allow protrusion;

Behavioral changes;

Front 221

Amount of sperm production is correlated to

Back 221

Testes size; Number of sertoli cells

Front 222

Seminiferous tubules

Back 222

Sperm producing cells - true germinal epithelium;

Not penetrated by blood or lymph (developing sperm cells could be recognized as foreign)

Front 223

Tunica albuginea

Back 223

Connective tissue (holds testis together)

Front 224

Rete testis

Back 224

Sperm transport from seminiferous tubules to the efferent ductules

Front 225

Efferent ductules

Back 225

6 - 12 tubules absorb fluid on travel ti epididymus

Front 226

Epididymus is broken into

Back 226

Head (caput);

Body (corpus);

Tail (cauda)

Front 227

Caput epididymus

Back 227

Functions in maturation of spermatozoa, fluid absorption

Front 228

Corpus epididymus

Back 228

Maturation of spermatazoa

Front 229

Cauda epididymus

Back 229

Final maturation and storage

Front 230

Vas Deferens

Back 230

Transport of sperm during ejeculation

Front 231

Spermatic cord

Back 231

Contains vas deferens, pampiniform plexus, external cremaster muscle, nerves

Front 232

Sertoli cells

Back 232

Somatic part of seminiferous tubules;

Support and provide nutrition for germ cells;

Helps form blood-testes barrier (tight junction);

Bind FSH;

Produce androgen binding protein and inhibin;

Converts androgen to oestradiol

Front 233

Myoid cells

Back 233

Boundary cells around seminiferous tubules;

Help form blood - testes barrier;

Contract to move spermatozoa out of seminiferous tubules

Front 234

Leydig cells bind

Back 234

LH (male cells)

Front 235

Sertoli cells bind

Back 235

FSH (male cells)

Front 236

Leydig cells

Back 236

Interstitial tissue between seminiferous tubules;

Bind LH;

Produce androgens

Front 237

Spermatogeneis

Back 237

36 - 60 days duration - slow continuous;

Injury - effects may be delayed;

Difficult to speed it up;

LH/FSH best to stimulate it

Front 238

Spermatocytogenesis

Back 238

Proliferation and formation of haploid spermatids from dormant spermatogonia in seminiferous tubules

Front 239

Meiosis in males occurs in

Back 239

Adluminal compartment

Front 240

Mitotic proliferation of spermatogonia occurs in

Back 240

Basal compartment

Front 241

Spermiogenesis

Back 241

Extensive cell remodelling to convert round spermatid to spermatozooan;

4 phases

Front 242

Spermatogenesis broken into two stages

Back 242

Spermatocytogenesis and spermiogenesis

Front 243

Spermiogenesis broken into four stages

Back 243

Golgi phase; Cap phase; Acrosome phase; Maturation phase

Front 244

FSH effects on males

Back 244

Determine testes size;

Rate of spermatogenesis, maintains meiosis;

Front 245

Testosterone effects on males

Back 245

Key male hormone;

Qualitative support of spermatogenesis;

Meiosis, spermatid maturition, sperm release

Front 246

Relationship between testosterone and LH

Back 246

Pulses matched but testosterone has much longer half life so no sharp drop off

Front 247

Which hormone is responsible for inducing male pattern behaviors in the brain

Back 247

Estrogen; Converted from testosterone by aromatase once within the brain

Front 248

Sperm structure: head

Back 248

Acrosome - contains hydrolytic enzymes and has two membranes;

Nucleus - condensed 1n chromatin;

Cytoskeletal structure

Front 249

Sperm Structure: Tail

Back 249

Central axoneme of 9 pairs + 2 microtubule fibers;

Made up of four components

Front 250

4 components of sperm tail

Back 250

Neck - connects head and tail;

Mid-piece - contains mitochondrial sheath;

Principal piece - fibrous sheath

End piece - no fibrous sheath

Front 251

Movement out of seminiferous tubules to rete testis by

Back 251

Active fluid secretion;

Muscular contraction by myoid cells and tunica albuginea;

Cilia in efferent ducts

Front 252

Functions of epididymus: Transport to vas deferens

Back 252

Local contractions;

Increase frequency of ejaculation increase transport by only 15%

Front 253

Functions of epididymus: Fluid reabsorbed

Back 253

Increase concentration and draw sperm towards epidudymis

Front 254

Functions of epididymis: Maturition

Back 254

Less of cytoplasmic droplet;

Androgen dependent; plasma membrane changes;

Progressive motility;

Ability to fertilize in body or tail

Front 255

Functions of epididymis: Storage

Back 255

80% of sperm outside of testes stored in epididymis tail;

Transit time: 11 - 13 days

Front 256

Fate of sperm in inactive animals

Back 256

Resorption of 50% in bulls;

87% loss in urine in rams

Front 257

Boar daily sperm production

Back 257

16 Billion sperm per day

Front 258

Ram daily sperm production

Back 258

10 Billion sperm per day

Front 259

Dairy bull daily sperm production

Back 259

7.5 Billion sperm per day

Front 260

Beef bull daily sperm production

Back 260

6 Billion sperm per day

Front 261

Stallion daily sperm production

Back 261

5 Billion sperm per day

Front 262

Fertilizing capability attained in

Back 262

The epidydimis: linear motility, acrosome, protein change, epididymal environment exposure

Front 263

Aberration of morphology

Back 263

Knobbed sperm, decapitated head, sterilizing tail stump, coiled tail, psuedo-droplet, corkscrew defect

Front 264

Causes of morphology aberration

Back 264

Handling of semen;

Environmental temperature;

Increased stress;

Increased frequency of ejaculation;

Freezing of semen;

Low nutrition

Front 265

Role of androgens part 1

Back 265

Present in high concentration due to androgen binding proteins;

Differentiation;

Maintenance of spermatogenesis;

Libido peck order;

Male secondary sex characteristics

Front 266

Role of androgens part 2

Back 266

Accessory sex glad functions - muscle and fluid production;

General body metabolism - anabolic;

Feed back regulation of LH and FSH;

Produced episodically in response to LH pulse

Front 267

Role of oestrogens in males

Back 267

Libido - conversion of testosterone to oestrogens;

Control of LH and FSH by negative feedback;

Stallion produces high oestrogen levels in urine

Front 268

Thermo regulation of testes

Back 268

Testis at lower temperature than body temp;

Scrotum design, muscle;

Blood supply;

Front 269

Scrotum temperature control

Back 269

Location of testes - away from body, air circulation;

Low insulation - thin skin, low fat and hair;

Sweat glands - richly endowed for cooling;

Tunica dartos - smooth muscle which lines the scrotal wall, changes testes location and scrotal surface area/ skin thickness;

External cremaster muscle - relax when hot contract when cold;

Thermoreceptors - nerves control response to temperature

Front 270

Blood supply control of testes temperature

Back 270

Pampiniform plexus - counter-current heat exchange, cooling of arterial blood supply, single artery surrounded by a network of veins;

Convoluted testicular artery on surface of testes

Front 271

Male problems in breeding

Back 271

Cryptochidism: Failure of testes to descend:

Bilateral - sterile but normal libido;

Unilateral - fertile but reduced production;

Front 272

Hermaphrodism

Back 272

Intersexes - both ovary and testicular tissues;

Can be both XX and XY - sterile and rare

Front 273

Hypoplasia

Back 273

Low frequency, heritable - incomplete development

Front 274

Defective sperm

Back 274

Some heritability - diadem, knobbed, decapitated, coiled

Front 275

Collection teasing requires

Back 275

Oestrous female;

Another female;

Dummy animal (boar and stallions);

Need proper restraint of teasers

Front 276

Proper collections require

Back 276

Training male;

Regulating temperature and AV water temperature;

Pressure within the AV with water amount;

Proper sexual preparation required to maintain sperm numbers

Front 277

Ejaculated sperm

Back 277

Maximal metabolism (ready to go);

Limited survival;

Must be protected against cold shock (can cause decapitation)

Front 278

Semen extenders

Back 278

Maintain osmotic balance; Provide nutrients;

Detoxify lactic acid, CO2 and H2O2;

Protect against chill damage;

Stabilize plasma and acrosomal membranes;

Prevent bacterial growth;

Protect against ice crystal formation when freezing

Front 279

Composition of extenders

Back 279

Energy source (sugars);

Prevent cold shock (milk or egg yolk - lipo proteins);

Buffer (Citrate, phosphate, tris)

Antibiotic (prevent bacterial growth)

Freezing - glycerol or DMSO

Front 280

Cold shock results in

Back 280

Irreversible loss of motility;

Metabolism decreases;

Membrane permeability increases & loss of molecules/ions out of the sperm;

Deformation of tail/mid piece

Front 281

Cooling shock is most affected by

Back 281

Rate of cooling - faster leads to greater cellular injury

Additives - can reduce injury

Front 282

Methods of storage

Back 282

Ambient temperature: limited time of use; most common used for boars (very susceptible to cold shock);

Chilling: 5 degrees; most common type used in horses (sperm very susceptible to cold shock);

Freeze: Long term storage (years)

Front 283

Freezing sperm

Back 283

Frozen in liquid nitrogen at -196 degrees;

Requires a cryoprotectant (glycerol used because sugar or proteins wont penetrate the cell);

50% killed or immotile;

Easy to transport and store; can be maintained after sires death

Front 284

Effect of long term storage on ewe pregnancy

Back 284

Small decrease in lambing rate no effect on number of lams born per pregnancy ( 1.9 lambs);

Bigger difference in Suffolk breed and stressed individuals

Front 285

Effect of freezing on boar semen

Back 285

Artificially induces capacitation so have shorter lifespan in the female tract

Front 286

Stallion semen has different fractions

Back 286

25% of ejaculates good quality;

50% of ejaculates moderate quality;

25% of ejaculates poor semen quality

Front 287

Thawing semen

Back 287

Rapid thawing required for most animals; Stallion sperm requires a mixture of two techniques and is very critical for working sperm

Front 288

Stallion AI is common in

Back 288

Sport horses, it allows stallions to continue to compete. Not allowed in thouroughbreds

Front 289

AI mares at which times

Back 289

Scan mares every six hours and AI 6 hours before or 6 hours after ovulation

Front 290

Sexing semen

Back 290

X chromosomes is larger and has more DNA;

Flow cytometer separates X and Y based on DNA content;

Can lead to lower fertility;

Front 291

Cytometer

Back 291

Able to separate X and Y bearing sperm but can lead to lower fertility (10-20% less), is expensive, and takes awhile;

Best to use with deep intrauterine insemination

Front 292

AI most widely developed in

Back 292

Cattle (AI)

Front 293

Advantages of AI

Back 293

Increased use of high GM sires;

Allow information banks on sires;

Allows for more control on sires;

Reduce venereal diseases

Front 294

Disadvantages of AI

Back 294

Must have oestrus detection;

Decreased conception rates in mares sows and ewes (when vaginal) (no difference in cows);

Handling of animal

Front 295

AI technique of cattle

Back 295

Palpate cervix via rectum;

Pass AI tube through cervix;

Expel semen into body of uterus;

Optimum time: toward end of heat -> 6h after

Front 296

AI technique of ewe (Basic)

Back 296

Insert speculum and and place semen in or near the cervix;

Optimal time: 8 - 14 hrs before ovulation

Front 297

AI technique of ewe (Laproscopic)

Back 297

Insert half of the semen dose through the cervix directly into the tip of each horn;

Optimal time: Fresh or chilled 12 - 18 hrs before ovulation; Frozen 6 hours before or after ovulation

Front 298

AI technique of sow

Back 298

Insert pipette and lock into the cervix, insert large volume;

Optimal time: 12 - 16 hrs before ovulation or 12 - 24 hrs after standing for boar

Front 299

Sperm is deposited into the vagina of

Back 299

Ewes, cows, goats, and primates

Front 300

Sperm is deposited into the uterus of

Back 300

sows, mares, bitches, and rodents

Front 301

Few sperm reach the ampulla because they are

Back 301

Lost by retrograde flow;

Phagocytosed by WBCs;

Caught in sperm resevoirs

Front 302

Sperm is transported through the female reproductive tract by

Back 302

Force of ejaculation;

Smooth muscle contractions of the female from PGF2Alpha and oxytocin in seminal plasma, oxytocine from vaginal distension, and E2 from pre-ovulatory follicle;

Sperm motility

Front 303

Cervical crypts

Back 303

Mucus traps many sperm;

Motility NB;

Gives final prolonged phase of transport

Front 304

Endometrial glands

Back 304

Binding of sperm cells to endometrial cell important in the bitch

Front 305

UTJ and Isthmus of oviduct

Back 305

Normal sperm binds to isthmus before ovulation;

Slow release from reservoirs due to sperm motility;

A few sperm pass into peritoneal cavity;

Hormone change gamete transport (P4 increase, E2 blocks)

Front 306

Oviduct

Back 306

Capacitation and acrosome reaction occurs;

Acts as sperm reservoir in lower isthmus and sight of fertilization at isthmus/ampullary juntion

Front 307

Excess sperm

Back 307

Phagocytosed in cervix and uterus;

Through to peritoneal cavity;

Loss through retrograde flow

Front 308

Capacitation

Back 308

Biochemical and biophysical changes;

Removal of sperm surface coating;

Rearangement of plasma membrane in sperm head;

Changes in plasma membrane phospholipids increasing motility

Front 309

Acrosome reaction

Back 309

Occurs after capacitation, induced by zona pellucida and cumulus cells;

Due to massive Ca influx through sperm head plasma membrane;

Release of enzymes bind and penetrate the zona pellucida causes fusing of sperm and ovum

Front 310

Fusion of sperm and ovum leads to

Back 310

Resumption of meiosis to completion;

Sperm nuclear membrane degrades, sperm nucleus decondenses -> gives rise to male pronucleus

Front 311

Block to polyspermy - Mechanism 1 (Zona Reaction)

Back 311

Species differences in mechanisms

Zona Reaction - cortical granules fuse with egg membrane, release hydrolytic enzyme which alters zona and prevents other sperm entry;

Main block in hamster, bitch, and ewe

Front 312

Block to polyspermy - Mechanism 2 (Vitelline block)

Back 312

Egg membrane alters in function preventing sperm entry, not well understood;

Main method in rabbits

Front 313

Block to polyspermy - Mechanism 3 (Combo of method 1 and 2)

Back 313

Occurs in rodents, cat, and possibly sow, cow, and mare

Front 314

Polyspermy incidence

Back 314

1 - 2%

Occurs if mating or AI is after time of ovulation; sows more common before oestrus is after ovulation;

Increased with aging ovum and AI into oviduct;

To avoid: prevent aging of gametes and do no AI after 6 hrs after ovulation