Reproduction Flashcards
define gelding
castrated male
define filly
female less than 2 years old
define colt
entire male less than 4 years old
define dam
mother
define sire
father
describe horses breeding cycle
seasonally polyoestrous
natural season spring to autumn due to increasing day length
oestrus cycle lasts 21 days
define mare
female adult
why do mares have spring to autumn oestrus naturally?
mares and foals easiest maintained at grass
time for foal to grow before winter
11 month gestation roughly
why are thoroughbred bred in early in the year?
want to race as old as possible in group so aim to birth as soon after january 1st by covering from valentines day
how are thoroughbred mare cycles manipulated?
lights
drugs
induces ovulation
define covering
mating
what are pre-breeding check on horses?
general health strangles clinical exam reproductive health ultrasound ovaries for follicle development reproductive diseases
how are horses checked for reproductive diseases?
swab clitoral fossa and sinus, endometrium
submit for cytology and culture
define teasing
male used to test if mare in season if she is receptive
what horses are used as a teaser?
low value pony
stud stallion
why are low value ponies usually used for teasing?
cheap
less consequence if injured during teasing
define stallion
entire male adult
list signs of oestrus in mares
lift tail winking vulva squirting urine wide legged stance acceptance of male
how do stallions react to mares in oestrus?
phlemen posture sniffing and nuzzling biting hindlimbs and perineum drop and erect penis covering mare
what are signs on ultrasound of best time to cover mares?
large follicle
uterine oedema
no free fluid in uterus
how do you observe cervix and what is seen for mares in oesturs?
clean and use speculum to visualise
red, engorged and saggy
how much thoroughbreds be covered to race?
natural
what are the ways of natural covering in horses?
in hand with stallion walked from behind
unassisted in herd, free in field
how are mares managed after being covered?
use teaser or ultrasound the following day
cover if still in oestrus
tease from day 18 and ultrasound at 12 days to see if pregnant
what are ways to collect semen for AI?
collect from dummy, ovariectomised mare or artificial vagina
how can stallions be encouraged to mate with dummy?
soak towel in urine from in season mare
stand mare in season near
what type of semen can be given to mares?
fresh
chilled
frozen
how is AI carried out?
give after induction of ovulation, based on scans
visualise with speculum and place insemination catheter into uterus
instil semen to uterine body
monitor mare with ultrasound
how is embryo transfer done in mares?
7-10 day blastocyst collected from donor and transferred to recipient
what are disadvantages of embryo transfer in mares?
expensive
need experience
need to synchronise donor and recipient
how is pregnancy in mares diagnosed?
ultrasound from 12 days failure to return to oestrus at day 21 eCG at 60 days oestrone sulfate at 120 days placental oestrogens in urine at 120 days
what is conception rate for horses?
80%
how do twins normally occur in horses?
non-synchronous ovulation
why do twin foals usually not survive pregnancy?
aborted at 5-7 months when demand exceeds placental surface area capacity for providing foals
one can survive and be born with mummified foal
how are twin foals usually managed when detected?
before day 35 prostaglandin given to reduce to one foal
checked on ultrasound
what is stage 1 foaling?
labour
foal enters pelvic canal stimulating cervical and vulval dilation
uterus contracts from tip to cervix
what nursing care can be done for stage 1 foaling?
wash perineum
tail bandage
describe what happens in stage 2 foaling?
allantois ruptures at cervical scar releasing fluids strong contractions from uterus voluntary abdominal contractions amnion visible with foal inside foal presents 2 toes and nose shoulders and body expelled hindlimbs retained in uterus so blood goes from placenta to foal umbilicus breaks when mare stands
what is stage 3 foaling?
uterine contractions from tip to cervix to invert and expel placenta
describe the equine placenta
epitheliochorial
6 layers
non-deciduate so foetal and maternal layers separate
diffuse so villi over whole placenta
how can you check for full placental expulsion?
distended with fluid
no tears
what are signs of dystocia in stage 2 foaling?
observed after rupturing of allantochorion
no amnion or foal at vulva after 5 minutes
no strong contractions within 10 minutes
no progression of foal for 5 minutes
how is dystocia in foaling treated?
assisted vaginal delivery vaginal delivery under GA C section embryotomy euthanasia
how is controlled vaginal delivery carried out in horses?
while horse under GA being prepped for c section
what is the prognosis for equine c section?
good when elective
if emergency depends on how long since starting stage 2 labour
what are the expectations of foals once born?
stand in 1 hour
suckle in 2 hours
placenta passed by 3 hours
what are the requirements for horses identification?
all born after 2005 need passport and microchip
when are passports applied for in horses?
by december 31st for year born or when foal 6 months
whichever later
what is included in horses passport?
owner details microchip ID certificate owner and vet signature vet stamp
how are microchips placed in horses?
scan neck to check doesnt have one
place in nuchal ligament
scan to check in place
