Veterinary Nonpregnant Female Reproduction

Front 1

what is the function of dopamine released from the hypothalmus

Back 1

inhibition of prolactin synthesis

Front 2

oxytocin function

Back 2

1.stimulation of uterine smooth muscle contractions
2.contraction of oviduct (gamete transport)
3.contraction of myoepithelial cells (milk let down)

Front 3

ferguson reflex

Back 3

stimulating release of oxytocin from the posterior pituitary upon stimulation of the cervix: not good in dystosia

Front 4

is GnRH antigentic in other speices

Back 4

no small protein hormone 10 amino acids

Front 5

is FSH antigenic in other speices

Back 5

yes

Front 6

FSH functions

Back 6

1.stimulation of follicular growth
2.stimulation of estradiol production by granulosa cells
3.induction of synthesis of LH receptors on granulosa cells

Front 7

LH functions

Back 7

1.stimulation of testosterone production (theca interna)
2.stimulation of estradiol production by granulosa cells
3.induction of ovulation of follicle
4.stimulation of progesterone secretion
5.maintenance of corpus luteum

Front 8

gonadotropin pulses change in amplitude and frequency during luteal phase and follicular phase

Back 8

luteal phase: amplitude increases and frequency decreases
follicular phase: amplitude decreases and frequency increases

Front 9

how does fescue affect the mammary gland

Back 9

mimmics dopamine: get no mammary gland developement, no milk production

Front 10

does oxytocin cause milk production

Back 10

no, just milk let down; prolactin causes prodcution

Front 11

intermediate pituitary gland

Back 11

not significant in most species
may become pathologically enlarged in the equine secondary to loss of dopamine regulation (equine cushings)

Front 12

ovarian production of steriod hormones, function of theca and granulosa cells

Back 12

theca cells: convert cholestrol to progestrone and then convert progesterone to androgens
granulosa cells: convert androgens to estrogens

Front 13

inhibin

Back 13

glycoprotein
comprised of alpha and beta subunits
produced by granulosa cells of the follicle
function:suppression of FSH secretion no effect on LH secretion

Front 14

PGF2alpha functions

Back 14

fatty acid hormone derived form arachidonic acid
functions: luteolysis
stimulation of uterine smooth muscle
involved locally in ovulation process

Front 15

primordial follicle

Back 15

oocyte
granulosa cells flat
basement membrane

Front 16

primary follicle

Back 16

larger than primordial
zona pellucida
cuboidal granulosa cells

Front 17

secondary follicle

Back 17

multiple layers of cuboidal granulosa cells surround primary oocyte
theca cells outside of basement membrane

Front 18

tertiary follicle

Back 18

FSH and LH receptors develop
FSH stimulates initial follicular development
fluid filled antrum forms within granulosa cell layer

Front 19

preovulatory follicle

Back 19

granulosa cells secrete estrogens
LH receptors form on granulosa cells
LH surge occurs in response to increased estradiol production and increased GnRH pulse frequency

Front 20

In the dog,
_____________
levels rise prior
to ovulation
• In other species,
___________
levels begin to
increase 1 - 2
days after
ovulation

Back 20

progesterone

Front 21

The duration of luteal function in large
animals is ____ days, depending on
the species

Back 21

14-18

Front 22

PGF has no role in CL
regression in ______,
_____ or _______

Back 22

PGF has no role in CL
regression in cats,
dogs or primates

Front 23

Transfer of PGF from the uterus to the
ovary occurs by either:

Back 23

Local counter-current system
(ruminants)
General systemic circulation
(horses and pigs)

Front 24

COUNTER-CURRENT PGF TRANSFER

Back 24

• PGF diffuses from the utero-ovarian
vein (high concentration) to the
ovarian artery (low concentration)
• With this mechanism, PGF can
regress the corpus luteum in the
ipsilateral ovary only

Front 25

SYSTEMIC PGF TRANSFER

Back 25

• PGF is secreted into the general
circulation
• Causes destruction of a CL on either
ovary
• PGF rapidly metabolized (lung)
• Produced in large quantities

Front 26

INDUCTION OF PGF RELEASE

Back 26

• Estradiol induces
formation of
oxytocin receptors
on endometrial cells
• Oxytocin secreted
from the corpus
luteum stimulates
uterine PGF release

Front 27

CL life-span can be prolonged by:

Back 27

• Pregnancy
• Pregnancy loss after maternal
recognition of pregnancy
• Chronic uterine infection
• Inadequate PGF release

Front 28

CL life-span may be shortened by:

Back 28

• PGF administration
• Endometritis (acute inflammation of the
uterus) causes premature PGF release
• Short estrous cycles (short luteal
phases) in a large animal suggests the
presence of a uterine infection

Front 29

FOLLICLE SELECTION

Back 29

• Dominant follicle produces estradiol and
inhibin which suppresses FSH
• Smaller follicles that still need FSH for
development begin to regress
• Dominant follicle continues to develop
under influence of LH

Front 30

NUTRITION: EFFECTS ON REPRODUCTION

Back 30

Nutrition effects many parameters:
• Attainment of puberty
• Duration of postpartum anestrus
• Gametogenesis
• Conception rates
• Embryonic mortality
• Sexual behavior

Front 31

Lactation suppresses reproductive activity
in the following species:

Back 31

• Pigs
• Cats
• Beef cattle

Front 32

Lactation has little effect on reproductive
activity in the following species:

Back 32

• Sheep
• Goats
• Horses
• Dairy cattle (milked not suckled)

Front 33

AGE-RELATED CHANGES IN
REPRODUCTION

Back 33

• Irregular cycles and prolonged
interovulatory intervals
• Decreased conception rate and decreased
litter size
• Anestrus (failure to cycle)
• Complete ovarian failure not commonly
recognized in domestic animals

Front 34

CATTLE
• Puberty -
• Seasonality -
• Reproductive
lifespan -

Back 34

CATTLE
• Puberty - 8 to 12
months of age
• Seasonality - not
seasonal breeders
• Reproductive
lifespan - 15 to 20
years

Front 35

CATTLE
Proestrus:

Back 35

• Period of rapid follicular growth
• Hormones - Progesterone low
Estrogens increasing
• Duration - 48 hrs

Front 36

CATTLE
Estrus:

Back 36

• Period of sexual receptivity
• Stands to be mounted by other cows
• Clear vaginal mucus
• Duration - 12 to 18 hrs
• Ovulation - 12 to 18 hrs after end of
estrus

Front 37

CATTLE
Metestrus:

Back 37

• Short period after estrus
• Bloody vaginal mucus - significance is
that it is too late to breed (source is
caruncular capillaries following rapid ↓ in E2
after ovulation)
• Duration - 2 days
• Progesterone - rising

Front 38

CATTLE
Diestrus:

Back 38

• Period of functional corpus luteum
• Not sexually receptive (no mounting)
• Duration - 16 days
• Progesterone - high

Front 39

CATTLE
Optimal Breeding Time:

Back 39

• From middle of estrus to 6 hours after
end of estrus (or 6 - 24 hrs after onset
of standing estrus)
• Ovum fertilizable for 8-10 hrs after
ovulation

Front 40

CATTLE
Postpartum Period:

Back 40

• Anestrus period
variable after calving
• Affected by season,
nutrition, suckling
• Dairy cows: 24 days
to ovulation
• Beef cows: 60 days
to ovulation

Front 41

SHEEP
Seasonality:

Back 41

• Short-day breeders
• Lamb in spring after
147 day pregnancy
• Some breeds cycle in
spring and fall

Front 42

SHEEP
Estrus:

Back 42

• Period ewe will stand for ram
• Mild mucus discharge, vulvar swelling
• Progesterone priming required for
expression of estrus
• Duration - 24-36 hrs
• Ovulation - near end of estrus

Front 43

sheep • Ovulation rate:

Back 43

1-2+
per cycle
• Increased plane of
nutrition increases
ovulation rate
(‘flushing’)
• Superovulation
possible with FSH or
eCG (PMSG)

Front 44

GOATS
Estrus:

Back 44

• Estradiol; No progesterone priming
• Vulva swollen, reddened, moist
• Rapid tail flagging
• Duration: 12- 24 (± up to 36) hrs
• Ovulation: near end of estrus

Front 45

HORSES
Estrus:

Back 45

• Period mare will stand for stallion
• Estrogen levels increasing
• Duration - 5 to 7 days
• Ovulation - 1-2 days prior to end of
estrus

Front 46

HORSES
Breeding Options:

Back 46

• Every other day beginning on the
second day of estrus until mare goes
out of heat
or
• Within 24 - 48 hrs prior to ovulation

Front 47

LH prolonged surge occurs only in _____

Back 47

horses

Front 48

HORSES
Postpartum Period:

Back 48

• No lactational anestrus
• Seasonal postpartum anestrus possible
(i.e. lack of follicular activity more dependent
on season than lactation)
• First ovulation (‘Foal Heat’ ovulation)
occurs 9-10 days after foaling

Front 49

PIGS
Diestrus:

Back 49

• Duration: 14 days
• CL not responsive to PGF until after
day 12 of cycle

Front 50

horse COOLED-TRANSPORTED SEMEN

Back 50

• Examine mares by palpation and
ultrasonography
• Begin on second day of heat
• Continue once daily until ovulation is
detected
• Order semen when a dominant follicle
reaches 35 to 40 mm in diameter
• Use hCG or GnRH to induce ovulation
at a predictable time