Equine Reproduction Flashcards
when do fillies and colts become mares and stallions?
filly <2 years female
colt <4 years entire male
what is an embryo?
conceptus under 50 days old
what is a foetus?
conceptus over 50 days old
what type of oestrus do mares have?
seasonally polyoestrus
when doe mares naturally cycle?
spring to autumn
what is mare cycle simulated and stopped by?
brought on by increasing day length and cease as days shorten
how long is a mares oestrus cycle?
21 days
what hormone causes the regression of the corpus luteum?
prostaglandin f2 alpha
why do mares need to foal in early spring/summer?
need foal to grow before winter
UK weather is unpredictable
when should mares be covered?
during the month after the month you wish them to foal in next year
why is it advantageous for thoroughbreds to be born early in the year?
when racing they race against all horses born in the same year as them
if born later they are less mature and less strong
when do breeders aim for their thoroughbred mares to foal?
after 1st January (to avoid being very young in their year) but close to
when are thoroughbred mares covered from?
valantines day
how are thoroughbred mares manipulated to come into season early?
lights and drugs
how can ovulation be induced in mares when they are sent to stud after their foal is born?
use of prostaglandin which causes corpus luteum regression and cycle within 2-3 days
what are the pre-breeding checks performed on a mare before or when she arrives at stud?
general health (clinical exam)
presence of strangles
reproductive health
how is the reproductive health of the mare checked before or on arrival at stud?
clitoral fossa and sinus swabs
what swabs should be used for clitoral fossa and sinus swabs?
ENT as smaller
what must clitoral fossa and sinus swabs be transported to the lab in?
Amies charcoal - prevents bacterial growth
what are clitoral swabs of mares checking for?
taylorella equigenitalis
pseudomonas aeruginosa
kiebsiella
what is caused by taylorella equigenitalis?
contagious equine metritis
what is significant about contagious equine metritis?
notifiable
how must clitoral fossa and sinus samples be sent to the lab?
name, date, time and site of sample
ensure swabs in date and sample is sent quickly
what are the pre-breeding checks performed at stud?
endometrial swabs for cytology and culture and sensitivity
ultrasound scan of ovaries
ultrasound scan of uterus
what are you looking for on a pr-breeding scan of the ovaries?
follicle developmet
what are you looking for on a pre-breeding scan of the uterus?
free fluid
cysts
what is teasing?
testing whether a mare is in season (behavioral oestrus) by seeing if she is receptive to a male horse at her head or rear
what stallion is normally used as a teaser stallion?
pony stallion
often low value and cheap to keep
sometimes use the stud stallion
what are the oestrus behaviours in mares?
lifts tail winks vulva squirts urine wide legged stance acceptance of male presence doesn't kick out at stallion tolerates stallion attention
what is the response to oestrus behaviour seen by stallions?
phlemen posture (vomeronasal organ) sniffs, nuzzles then bites hindlimbs and perinuem drops penis penile erection will cover mare if allowed
when can the best time to cover a mare be determined?
ultrasound which shows larger follicle, uterine oedema that is beginning to wane and no free fluid in uterus
how large should the follicle be pre ovulation?
approx 5cm diameter
how should the mare be prepped when viewing her cervix?
clean perineum with warm soapy water - no hibi or iodine
how is cervix visualised?
speculum and torch
what does the cervix look like during oestrus?
red
engorged
saggy
what does the cervix look like in dioestrus?
pale
small
tight
high up off vestibule floor
what method of covering must be used to be weatherbys registered?
natural (AI not permissable)
covering certificate will be issues
what may the stallion handler do during covering to ensure ejaculation has occurred?
palpate ventral penis
when does in hand covering occur?
once teasing and scanning has determined appropriate time
what safety equipment is needed for covering in hand?
human - hat, gloves, boots
mare - wither guard, hind boots, bridle, hobbles, tail bandage
stallion - specific bridle/chain, lunge line, fore feet boots
what should be done the day following covering?
tease or ultrasound to see if still in oestrus
what will happen if the mare is still in oestrus following covering?
may cover again (ideally every other day of oestrus)
what will happen if the mare is not in oestrus following covering?
manage as normal
tease again from 18 days
ultrasound from 12 days to see if pregnant
where does unassisted covering occur?
in herd or individual
short term or permanent (e.g. native herds)
free in field and supervised
how is unassisted covering managed?
timings determined by horses
less control / human intervention
natural
unsure fo exact dates
what are the 3 types of AI semen available?
fresh - local stallion
chilled - stallion in country
frozen - globally
how is semen collected for AI?
using a dummy and AV (integral or separate)
use towel soaked in in season mares urine or have an in season mare nearby to encourage stallion
is semen collection often performed using a mare?
no - ethically questionable
need sedation and repeated restraint
dummy much more common
what is found in an artificial vagina?
filled with warm water lined lubricated insulated semen collection vessel on end filter between chamber and semen collection pot
what temperature should the water in an AV be?
crucial
38 degrees but varies between stallions