Equine reproduction & other Flashcards
How is the equine uterus connected in the body?
hangs from the broad ligament
- nerves, vessels etc. run through it
mesometrium
mesosalpinx
mesovarium
etc.
equine ovary shape
bean shaped
and they’re “inside out”: medulla on the outside, cortex on the inside.
ovulatory fossa where ovulation occurs
estrus length in mares
estrus = heat
5-7 days
estrus cycle length in mares
21 days
estrus length in cows?
estrus = heat
10-15 hours
“collection” of oocytes by what structures?
infundibulum of oviduct with fimbriae
in mares, unfertilized oocytes remain in the
oviducts
ampullary-isthmic junction is sorta like a
a control point for the fertilized oocyte, it begins to produce prostaglandins.
estrus cycle phases in mares
anestrus
diestrus
estrus
(no pro- or met- in mares like in cows)
in what phase of the estrus cycle do cows ovulate?
after estrus, during metestrus
which species have a post-estrus phase?
cats
(9 days estrus and 9 days post-estrus)
Reproduction season in mares?
season during which ovulations occur
April to September
(there can be some exceptions of course)
Non-reproductive season in mares?
Anovulatory period or anestrus
December - January normally
Transition periods between estrus and anestrus in mares?
spring: feb- march
autumn: oct- nov
melatonin supresses what in mares…?
melatonin increases in dark seasons so during winter, suppresses GnRH and thus FSH and LH production which is why mares do not ovulate in the autumn and winter.
in the spring, melatonin concent. decrease inducing what in mares?
increased release of GnRH and in turn FSH and LH
may be 1-2 follicular waves prior to successful ovulation.
which hormone is responsible for heat signs
estrogen produced in the ovarian follicles
size of a normal preovulatory equine follicle
4-5 cm
if there remain follicles in autumn they may grow too big and surpass 5cm in size.
called anovulatory hemorrhagic follicles
they disappear during anestrus/winter period
follicles that do not successfully ovulate? (mares)
anovulatory hemorrhagic follicles
(in cows, these typically develop cysts instead)
At the end of each cycle, mares have how many follicles
1 dominant and several secondary follicles
(sometimes there are 2 or even 3 dominant follicles but this isn’t desired)
stallion reach sexual maturity when?
10-24 months
mares reach sexual maturity when?
12-24 months
but first breeding shouldn’t be before 24 months so they have time to grow up.
life span of stallion sperm in mare repro.tract?
survival time with fertilizing capacity?
2-4 days
1-2 days
stallion semen/ejaculate volume
20-100 ml
for the test its acceptable to say “around 100ml”
if the volume is higher, the concentration is lower and vice versa.
stallion sperm output and production is influenced by: (6)
season (photoperiod)
testicular size
age (older animals’ testicles begin to shrink eventually)
testosterone production
frequency of ejaculation
behavior
where are spermatozoa produced?
seminiferous tubules, Leydig cells
(sertoli cells help with the environment)
name the types of artificial vaginas
closed systems:
missouri
japanese
CSU (colorado)
open systems:
polish (no direct connection to collection bottle/container)
french (INRA)
condom (equine version obviously - stallion is allowed to breed mare and then you collect condom contents (not in use as commonly as others))
stallion semen is frozen and stored in what volumes?
0.5-1 ml straws
how many progressively motile sperm needed per insemination?
500 million
(there are like 6 billion or more per ejaculate)
types of semen used for inseminations? (3)
fresh
cooled
frozen
what happens to sperm after capacitation when no oocyte present?
death
macroscopic features to assess about stallion semen
after filtering out the clumps that come from the accessory glands (vesicular in stallion, bulbourethral in boars):
cloudiness
fluidity
color
odor
(volume)
DSO =
daily sperm output
Mares are artificially inseminated into what part of the repro organ?
into the uterus
multiple inseminations can be performed 24-48 hours apart
contrary to bovine insemination, for mares you do not need to guide via the rectum. you go intravaginally.
How long is an equine oocyte fertile for after ovulation?
approx. 8 hours
how long does fresh semen remain viable?
with an extender and at room temperature, about 6h
inside mare repro. tract, lasts longer
Cooled semen: protocol
keep semen at 5’C
no need to warm the semen before insemination
follicle must be a minimum of 3,5 cm in diameter, check by U/S (ovulation usually 36-40h later)
frozen semen: protocol
more expensive and laborious
lower fertility
low volume (0.25- 0.5 ml straws)
warm in a water bath for 30s at 37’C
what condition can mares get after artificial insemination besides pregnancy?
sperm induced endometritis is problematic
(causes fluid accumulation in the uterus and can be seen on ultrasound)
