Equine Male Flashcards
what are the effects of FSH, LH, and testosterone in the male horse?
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
when does testicular decent happen in male horses
30 days before birth to around 10 days after birth
spermatozoa can be seen as early as how old in colts?
14 months, but normally a few months later
____ increases at around 20 months and this is what promotes ____
testosterone, puberty
should you turn a yearling colt out with mares?
you can!! :)
T or F: if a colt is allowed to breed he can produce a pregnancy
true
when is the best time to castrate?
usually 8-12 months, Tovah likes around 1 year. Much easier than a mature horse
do stallions have seasonality? explain
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!
when a stallion is “out of season”, what differences are there?
testes are lighter, fewer leydig cells, fewer sertoli cells, produce less sperm cells, hormones in lower concentrations
what are things we need to know for a breeding soundness exam for stalions?
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
on your general health exam of the stallion, what things do you need to know about?
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?
exam of the external genitalia includes
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?
for testes, greater than ____cm is considered good
8
what is included in the exam of the internal genitalia?
ampulla, vesicular gland, prostate gland
function of epididymis, apullae, vesicular, prostate, and bulbourethral glands
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
what is a semen extender?
nutrients and fluid to keep the semen alive for around 48hrs
true or false: all stallions respond to extenders differently
truuuuu bestie
for semen collection in stallions, what methods are available?
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)
which drugs can be used for chemical ejaculation?
Imipramine: give 1-2 hrs before collecting
Xylazine: give in combo with imipramine after initial teasing, ejaculation will happen within 3-15mins
what drug should you NOT use to arouse a stallion?
acepromazine
when evaluating the semen, what things are you evaluating?
gross appearance, volume, motility, morphology, longevity, contamination or infection
when assessing motility, what things are you looking at?
make sure to assess with and without an extender
total motility %
progressively motile % (moving forward)
non progressively motile % (moving in circles)
what should be done for every new stallion presented for shipment of fresh cooled semen?
testing of semen extenders: extend the semen in several extenders and assess motility at 24 and 48 hours
what causes cryptorchidism in stallions?
genetic predispositions, or insufficinet androgens
can crypt testes still make sperm? how about testosterone?
can’t make sperm because it’s too hot, but can make testosterone just fine
how do you diagnose crypt?
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
what is azoospermia? how do you find out the cause and work this up?
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
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?
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?
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?
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
how do you interpret an alkaline phosphate measurement for JOEY?
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
clinical signs of a blocked ampullae? treatment?
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
when treating a blocked ampullae and doing serial collections, what should you expect the semen to be like?
clumps of sperm, lots of sperm, lots of detached heads
what is retrograde ejaculation? diagnosis and treatment?
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
if your AP is high this means vesicular emission did happen..what are your ddx? how to investigate
testicular hypoplasia, testicular degeneration
further workup: ultrasound, biopsy
what is endocrineology testicular degeneration
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
what is hemospermia? what is the initial CS and why?
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
list some possible causes of hemospermia
SCC, habronema (contagious nematode), equine coital exanthema (EHV 3), urethritis, urethral rent (tear in urethra) , seminal vasculitis
how to diagnose hemospermia?
can be difficult! do a PE, semen collection/examination including viral testing.cytology, urethral and bladder endoscope
for the treatment of hemospermia, ____ is neccessary
sexual rest
what is EHV3? CS? tx?
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
what is CEM? CS?
contagious equine metritis caused by Taylorella equigenitalis
CS: vaginitis, cervicitis, endometritis, purulent vag discharge, abortion, infertility, no signs in stallions
why is CEM more common in TBs?
because it’s spread via live cover and this is how TBs are bred
T or F: you can prevent CEM with antibiotics in the extneder for AI
true
remember: no way to prevent for live cover
how to diagnose CEM?
swabs from cervix/uterus
for males: must swab erect penis (sus)
treatment of CEM?
wash external genitalia with disinfectant soap, apply topical antibiotic ointment for 5 days
true or false: CEM is a reportable disease
true!!!!! it has never been detected in Canada
what is equine viral arteritis?
an arterivirus, an RNA virus
a systemic disease that affects repro tract
spread via resp secretions
clinical signs of equine viral arteritis?
edema of the prepuce and scrotum, really high fever, short term subfertility, abortion storms in mares, stallions become life long carriers
prevention of equine viral arteritis
vaccination! but you can’t differentiate between vaxed and carrier stallions
proper way to do serological testing for equine viral arteritis?
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
what cancer type is common on ze pepe
SCC
treatment of SCC?
surgical excision wide margins, cryotherapy (cold)
