Equine Male

Question 1

what are the effects of FSH, LH, and testosterone in the male horse?

Answer 1

FSH: stimulates sperm production
LH: need it to complete sperm production
testosterone: promotes development and function of the accessory sex glands, secondary sex characteristics, and mating behavior

Question 2

when does testicular decent happen in male horses

Answer 2

30 days before birth to around 10 days after birth

Question 3

spermatozoa can be seen as early as how old in colts?

Answer 3

14 months, but normally a few months later

Question 4

____ increases at around 20 months and this is what promotes ____

Answer 4

testosterone, puberty

Question 5

should you turn a yearling colt out with mares?

Answer 5

you can!! :)

Question 6

T or F: if a colt is allowed to breed he can produce a pregnancy

Answer 6

true

Question 7

when is the best time to castrate?

Answer 7

usually 8-12 months, Tovah likes around 1 year. Much easier than a mature horse

Question 8

do stallions have seasonality? explain

Answer 8

they are, but they DO produce spermatozoa all year and they CAN breed in the off season. daylight controls their “season”–>horses near the equator will be in season all year long!

Question 9

when a stallion is “out of season”, what differences are there?

Answer 9

testes are lighter, fewer leydig cells, fewer sertoli cells, produce less sperm cells, hormones in lower concentrations

Question 10

what are things we need to know for a breeding soundness exam for stalions?

Answer 10

History: general and breeding history (have they bred before, are they trained, was it AI or live cover, etc)
General health exam
exam of the internal and external genitalial
semen collection
testing of semen extenders

Question 11

on your general health exam of the stallion, what things do you need to know about?

Answer 11

blindness? lameness or ataxia possibly affecting breeding? hereditary defects? confomration of legs and feet? vaccine status? OCD lesions? any pelvic or back pain that would interfere with breeding?

Question 12

exam of the external genitalia includes

Answer 12

testes: normal size and consistency, are they fully distended into the scrotum, how do they look on US?

penis and prepuce: appear normal and free of any sores, infections, tumors?

Question 13

for testes, greater than ____cm is considered good

Answer 13

8

Question 14

what is included in the exam of the internal genitalia?

Answer 14

ampulla, vesicular gland, prostate gland

Question 15

function of epididymis, apullae, vesicular, prostate, and bulbourethral glands

Answer 15

epididymis: transport sperm to deferent duct, where sperm mature and are stored

ampullae: widening of the deferent duct, surrounded by smooth muscle that contracts to push sperm into the urethra

vesciular/prostate/bulbo: add gel and fluid to the semen

Question 16

what is a semen extender?

Answer 16

nutrients and fluid to keep the semen alive for around 48hrs

Question 17

true or false: all stallions respond to extenders differently

Answer 17

truuuuu bestie

Question 18

for semen collection in stallions, what methods are available?

Answer 18

are they trained on a dummy? with or without a teaser female? stallions are picky…you need to know this stuff? what type of “horse vag” does he like (EW OMG)

Question 19

which drugs can be used for chemical ejaculation?

Answer 19

Imipramine: give 1-2 hrs before collecting

Xylazine: give in combo with imipramine after initial teasing, ejaculation will happen within 3-15mins

Question 20

what drug should you NOT use to arouse a stallion?

Answer 20

acepromazine

Question 21

when evaluating the semen, what things are you evaluating?

Answer 21

gross appearance, volume, motility, morphology, longevity, contamination or infection

Question 22

when assessing motility, what things are you looking at?

Answer 22

make sure to assess with and without an extender

total motility %
progressively motile % (moving forward)
non progressively motile % (moving in circles)

Question 23

what should be done for every new stallion presented for shipment of fresh cooled semen?

Answer 23

testing of semen extenders: extend the semen in several extenders and assess motility at 24 and 48 hours

Question 24

what causes cryptorchidism in stallions?

Answer 24

genetic predispositions, or insufficinet androgens

Question 25

can crypt testes still make sperm? how about testosterone?

Answer 25

can’t make sperm because it’s too hot, but can make testosterone just fine

Question 26

how do you diagnose crypt?

Answer 26

ultrasound of the external inguinal region and the abdominal cavity

can do an hCG stim test and compare testosterone levels 1-2 hours after you give the hCG
single blood sample: high anti-mullerian hormone

Question 27

what is azoospermia? how do you find out the cause and work this up?

Answer 27

abscence of sperm in the ejaculate (many causes)

workup:
- did the horse complete a full ejaculatory process (flagging of the tail, pulsations at the base of the pp, prescence of gel)
- if yes, you need to rule out blocked ampullae, retrograde flow into bladder, an injury to the testes causing degeneration

Question 28

if you get a semen sample with no sperm, and you discover the ejaculatory process is incomplete, what are some things you need to consider?

Answer 28

how does the collection area look? is it slippery? is the phantom too high or too low?

are there problems with the temperature or pressure?

is the horse in pain?

are there any drug effects?

environmental factors?

Question 29

you’re investigating a stallion named JOEY and he has azoospermia and you determined the ejaculatory process to be complete. What is one test you want to do?

Answer 29

We need to see if seminal emission occured, aka, did the accessory glands secrete their stuff?

measure to alkaline phosphate level: this determines if the testicular and epididymal fluid is present in the seminal plasma

Question 30

how do you interpret an alkaline phosphate measurement for JOEY?

Answer 30

if AP is <100 IU/I, this means NO seminal emission occured and there is either blocked ampullae or retrograde ejaculation

if AP is 7000 to 20,000, there was seminal emission, and you need to investigate further ddx and consider a testicular defect

Question 31

clinical signs of a blocked ampullae? treatment?

Answer 31

azoospermia, low AP levels, lots of separated tail sperm, can happen after sexual rest

treatment: trans rectal massage, oxytocin (stimulate smooth muscle of ampullae), serial semen collections

Question 32

when treating a blocked ampullae and doing serial collections, what should you expect the semen to be like?

Answer 32

clumps of sperm, lots of sperm, lots of detached heads

Question 33

what is retrograde ejaculation? diagnosis and treatment?

Answer 33

when the semen goes into the bladder; failure of the bladder sphincter

dx: free catch or U cath sample to look for sperm

tx: Imperamine to promote closure of sphincter

Question 34

if your AP is high this means vesicular emission did happen..what are your ddx? how to investigate

Answer 34

testicular hypoplasia, testicular degeneration

further workup: ultrasound, biopsy

Question 35

what is endocrineology testicular degeneration

Answer 35

advancing degeneration often age related: decrease in estrogen and inhibin and an increase in FSH

more advanced degeneration: decrease in testosterone and increase in LH

Question 36

what is hemospermia? what is the initial CS and why?

Answer 36

blood in the sperm! ruh roh!!!

infertility is first sign because RBCs are pro-inflammatory in the mare :(

other signs: could be blood on penis, vagina, etc

Question 37

list some possible causes of hemospermia

Answer 37

SCC, habronema (contagious nematode), equine coital exanthema (EHV 3), urethritis, urethral rent (tear in urethra) , seminal vasculitis

Question 38

how to diagnose hemospermia?

Answer 38

can be difficult! do a PE, semen collection/examination including viral testing.cytology, urethral and bladder endoscope

Question 39

for the treatment of hemospermia, ____ is neccessary

Answer 39

sexual rest

Question 40

what is EHV3? CS? tx?

Answer 40

equine coital exanthema

veneral disease which is spread thru fomites, sexual contact, flies carrying infected vaginal discharge

CS: nodules, vesicles and pustules appear and rupture, ulcers on the teats, lips, nasal mucosa, secondary bacterial infections. NO systemmic signs and does not impact fertility or abortion

tx: sexual rest, antibiotic ointment

Question 41

what is CEM? CS?

Answer 41

contagious equine metritis caused by Taylorella equigenitalis

CS: vaginitis, cervicitis, endometritis, purulent vag discharge, abortion, infertility, no signs in stallions

Question 42

why is CEM more common in TBs?

Answer 42

because it’s spread via live cover and this is how TBs are bred

Question 43

T or F: you can prevent CEM with antibiotics in the extneder for AI

Answer 43

true

remember: no way to prevent for live cover

Question 44

how to diagnose CEM?

Answer 44

swabs from cervix/uterus

for males: must swab erect penis (sus)

Question 45

treatment of CEM?

Answer 45

wash external genitalia with disinfectant soap, apply topical antibiotic ointment for 5 days

Question 46

true or false: CEM is a reportable disease

Answer 46

true!!!!! it has never been detected in Canada

Question 47

what is equine viral arteritis?

Answer 47

an arterivirus, an RNA virus

a systemic disease that affects repro tract

spread via resp secretions

Question 48

clinical signs of equine viral arteritis?

Answer 48

edema of the prepuce and scrotum, really high fever, short term subfertility, abortion storms in mares, stallions become life long carriers

Question 49

prevention of equine viral arteritis

Answer 49

vaccination! but you can’t differentiate between vaxed and carrier stallions

Question 50

proper way to do serological testing for equine viral arteritis?

Answer 50

test before vaccination (because afterwards you can’t differentiate)

if they have no antibodies, they have never been exposed

if they do have antibodies, this is either from an infection of from a vaccination. You can do virus testing of the semen, and if this is negative, they are vaccinated, and if positive, they are a carrier

if positive for antibodies you need paired/serial testing to prove it

Question 51

what cancer type is common on ze pepe

Answer 51

SCC

Question 52

treatment of SCC?

Answer 52

surgical excision wide margins, cryotherapy (cold)