Equine reproduction & other

Question 1

How is the equine uterus connected in the body?

Answer 1

hangs from the broad ligament

• nerves, vessels etc. run through it

mesometrium
mesosalpinx
mesovarium
etc.

Question 2

equine ovary shape

Answer 2

bean shaped

and they’re “inside out”: medulla on the outside, cortex on the inside.

ovulatory fossa where ovulation occurs

Question 3

estrus length in mares

Answer 3

estrus = heat

5-7 days

Question 4

estrus cycle length in mares

Answer 4

21 days

Question 5

estrus length in cows?

Answer 5

estrus = heat

10-15 hours

Question 6

“collection” of oocytes by what structures?

Answer 6

infundibulum of oviduct with fimbriae

Question 7

in mares, unfertilized oocytes remain in the

Answer 7

oviducts

Question 8

ampullary-isthmic junction is sorta like a

Answer 8

a control point for the fertilized oocyte, it begins to produce prostaglandins.

Question 9

estrus cycle phases in mares

Answer 9

anestrus
diestrus
estrus

(no pro- or met- in mares like in cows)

Question 10

in what phase of the estrus cycle do cows ovulate?

Answer 10

after estrus, during metestrus

Question 11

which species have a post-estrus phase?

Answer 11

cats

(9 days estrus and 9 days post-estrus)

Question 12

Reproduction season in mares?

Answer 12

season during which ovulations occur

April to September

(there can be some exceptions of course)

Question 13

Non-reproductive season in mares?

Answer 13

Anovulatory period or anestrus

December - January normally

Question 14

Transition periods between estrus and anestrus in mares?

Answer 14

spring: feb- march
autumn: oct- nov

Question 15

melatonin supresses what in mares…?

Answer 15

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.

Question 16

in the spring, melatonin concent. decrease inducing what in mares?

Answer 16

increased release of GnRH and in turn FSH and LH

may be 1-2 follicular waves prior to successful ovulation.

Question 17

which hormone is responsible for heat signs

Answer 17

estrogen produced in the ovarian follicles

Question 18

size of a normal preovulatory equine follicle

Answer 18

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

Question 19

follicles that do not successfully ovulate? (mares)

Answer 19

anovulatory hemorrhagic follicles

(in cows, these typically develop cysts instead)

Question 20

At the end of each cycle, mares have how many follicles

Answer 20

1 dominant and several secondary follicles

(sometimes there are 2 or even 3 dominant follicles but this isn’t desired)

Question 21

stallion reach sexual maturity when?

Answer 21

10-24 months

Question 22

mares reach sexual maturity when?

Answer 22

12-24 months

but first breeding shouldn’t be before 24 months so they have time to grow up.

Question 23

life span of stallion sperm in mare repro.tract?
survival time with fertilizing capacity?

Answer 23

2-4 days
1-2 days

Question 24

stallion semen/ejaculate volume

Answer 24

20-100 ml

for the test its acceptable to say “around 100ml”

if the volume is higher, the concentration is lower and vice versa.

Question 25

stallion sperm output and production is influenced by: (6)

Answer 25

season (photoperiod)
testicular size

age (older animals’ testicles begin to shrink eventually)
testosterone production

frequency of ejaculation
behavior

Question 26

where are spermatozoa produced?

Answer 26

seminiferous tubules, Leydig cells

(sertoli cells help with the environment)

Question 27

name the types of artificial vaginas

Answer 27

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))

Question 28

stallion semen is frozen and stored in what volumes?

Answer 28

0.5-1 ml straws

Question 29

how many progressively motile sperm needed per insemination?

Answer 29

500 million

(there are like 6 billion or more per ejaculate)

Question 30

types of semen used for inseminations? (3)

Answer 30

fresh
cooled
frozen

Question 31

what happens to sperm after capacitation when no oocyte present?

Answer 31

death

Question 32

macroscopic features to assess about stallion semen

Answer 32

after filtering out the clumps that come from the accessory glands (vesicular in stallion, bulbourethral in boars):

cloudiness
fluidity
color
odor
(volume)

Question 33

DSO =

Answer 33

daily sperm output

Question 34

Mares are artificially inseminated into what part of the repro organ?

Answer 34

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.

Question 35

How long is an equine oocyte fertile for after ovulation?

Answer 35

approx. 8 hours

Question 36

how long does fresh semen remain viable?

Answer 36

with an extender and at room temperature, about 6h

inside mare repro. tract, lasts longer

Question 37

Cooled semen: protocol

Answer 37

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)

Question 38

frozen semen: protocol

Answer 38

more expensive and laborious
lower fertility
low volume (0.25- 0.5 ml straws)

warm in a water bath for 30s at 37’C

Question 39

what condition can mares get after artificial insemination besides pregnancy?

Answer 39

sperm induced endometritis is problematic

(causes fluid accumulation in the uterus and can be seen on ultrasound)