Equine Flashcards
What is the birth date of all foals?
1st January
How long is gestation?
11 months
Which months should covering take place in?
Feb-June/July
What kind of oestrus do horses show?
Seasonally polyoestrus (Spring-Autumn)
How long is the oestrus cycle?
21-23 days
How long is the oestrus period?
2-4 days
How long is the dioestrus period?
15-17 days
How does melatonin affect GnRH?
Antagonises
From when do you give the mare artificial light?
15th December
How long does light take to work in the mare?
6 weeks
Do you give dopamine or dopamine antagonists to induce breeding?
Antagonists
Why do you give progesterone during transitional oestrous?
May not involve ovulation so progesterone stops cycling then taking this away causes full oestrus
What can you give to mimic dioestrus?
PGs
Why might you use intrauterine glass marbles to mimic pregnancy and stop cycling?
Because can’t give drugs to a racehorse
Which vaccine can you give to working animals to stop cycling?
Porcine GnRH
Which three things does venereal disease screening look for?
Taylorella (CEM), Pseudomonas, Klebsiella
Which transport medium do you use for a clitoral swab?
Amies charcoal
When is the only time you can get an endometrial swab?
In oestrus because cervix is open here
How can mares wink clitoris?
Because have circular and longitudinal muscle
Which orientation should the anus and vulva be?
Vertical
What happens to the anus with age?
Sinks inwards
Which seals prevent infection entry?
Vulval and vaginal
Where should the pelvis shelf be?
At the top of the vulval opening
What do endometrial epithelial cells look like?
Long and large with a wispy cytoplasm
What do vaginal/cervical cells look like?
Keratinised
What does the ovary look like on ultrasound if in season?
Orange segment and ovulation fossa with one large follicle
What three things can you check for 48 hours after mating?
Ovulation, twin ovulation, fluid in uterus
What happens if inflammatory response has not resolved after 48 hours?
Mare is “susceptible” so cover only once here
Above what age is endometriosis normal?
9
What are three changes that occur with age?
Gland “nests”, fibrosis, excessive lymphatic lacunae
For how long is stallion sperm viable?
72 hours
How often should you examine for oestrus?
24-48 hr
Why do mares need boots?
To prevent kicking
Why do mares need a rubber ring?
For stallion biting
Where does fertilisation occur?
The oviducts
How long does it take for the conceptus to enter the uterus?
4-6 days
What months have peak testosterone?
April to May
How long does spermatogenesis take?
56 days
What is one problem with testicle damage?
Causes 2 months infertility
What is the lead rope like in stallions?
Longer
Why are teaser stallions used?
To avoid actual stallion getting kicked
What is one problems with scrotal damage?
Anti-sperm antibodies
How many degrees can the testicle swing without injury?
90-180
What happens if the testicle twists too far?
Pampiniform plexus occludes
What correlates with the daily sperm output?
Size of testicle
What does daily sperm output determine?
Number of mares can breed with
What can cryptorchids produce large amounts of?
Androgens
Which breeds commonly get cryptorchid?
TB and Welsh Pony
What are the two types of cryptorchid?
Partial and complete
How can you tell if any testicular tissue has been left behind after castration?
Anti-mullerian hormone levels
Which accessory glands do horses have?
All four
How many thrusts does ejaculation take?
3-5 (up to 8)
Which places do you swab in the stallion?
Urethra, urethral fossa, penile sheath
What is a high risk for sedation?
Acepromazine
What temperature should the artificial vagina be?
44-48 degrees
Where is the gel in the semen from?
The seminal vesciles
Why must you use a bottle warmers for the sperm?
To prevent cold shock and to keep dark
Why should you wash but not disinfect the stallion before collection?
Irritates and removes natural flora
Which kind of mares can you use for live mare collection?
Oestrus, PG, IM oestradiol, ovariectomised, dummy
Which side should handlers and collectors stand?
The same side
For how many days should you collect ejaculate?
5-7 days
What can you do instead of going every 5-7 days?
Collect two samples an hour apart and use the second one
What is the second sample like compared to the first?
50% less
How should you evaluate the semen and in what order?
Volume, colour, pH, motility, conc, morphology, cytology, bacteriology
What should semen volume be?
70ml
What should semen pH be?
7.2-7.6ml
Why should you test the pH quickly?
Metabolic activity of sperm increases it
What happens to motility over time?
Decreases
Why do you add extender to the semen?
Can clump
How many semen should be moving?
75-90%
How many semen should be moving straight?
55-80%
How many sperm should still be moving after 6 hours?
10%
How many should still be moving after 24 hours in extended semen?
10%
Which stain do you use to see the live/dead ratio?
Nigrosin/eosin
What % should be live?
80%
What % should be morphologically normal?
70%
How do you work out the TNM?
total number x % morphologically normal x % progressively motile
Where do primary sperm defects occur?
Within the testes e.g. extra heads, bent
Where do secondary defects occur?
Within the epididymis and efferent tracts e.g. retained droplet
What is success rate per cycle with chilled semen?
55-70%
What is success rate per cycle with frozen semen?
35-59%
After which time limit must you remove gel and use extender?
If not using semen after 10 mins
After which time limit must you remove seminal plasma and use light and air proof container?
If storing for 2-6 hours
Why do you remove seminal plasma?
To decrease capacitation
What do you use if chilling for use in the next couple of days?
An equitainer
How quickly does an equitainer cool the semen?
0.3 degrees per minute
What temperature does an equitainer keep semen at?
4-6 degrees for 3 days
What is an example of a cryoprotectant?
Glycerol
What temperature is semen frozen at?
-196
Why must straws all freeze at the same time?
To avoid cellular damage
What is the volume of a straw?
0.5ml
What do larger straws have in the middle?
A hole
What must the motility be in frozen semen?
30%
Which mares are the hardest to breed from?
Old, competing
When should you inseminate fresh semen?
Up to 48 hours before ovulation
When should you inseminate chilled semen?
Up to 24 hours before ovulation
When should you inseminate frozen semen?
From 6 hours before to 6 hours after ovulation (usually before)
What must dummy mares have at the front?
A head
Why don’t some stallions like dummy mares?
Rubs their knees
What do you use to wash the mare before covering?
Water only
Why can’t you use a normal syringe for insemination?
Rubber is spermicidal
What is horse cervix like?
Short, simple
Where do stallions ejaculate?
Into the uterus because the cervix dilates
How many sperm are in one AI dose?
500 million
How do you synchronise donor and recipient during embryo transfer?
Progestagen and PGF2a
What day do you flush during embryo transfer?
7-8
Why do you flush earlier if embryo splitting?
ICM will have formed
What does the Wilsher method do?
Sucks cervix back towards the vulva so can see clearly and introduce less infection
Why can’t you give drugs to induce superovulation in horses?
They can only exit by ovulation fossa
What happens if you mate a large stallion with a small mare?
Runty foal
From which day does the embryo secrete PGE2 to relax the oviduct sphincter?
4-5
Until which day does the conceptus remain spherical and mobile?
16
Between which days does the conceptus have a glycoprotein capsule for physical protection and anti-adhesive?
6.5-23
From which day does the blastocyst produce oestrogen?
10
At what day does the chorionic girdle invade the endometrium to form the cups?
28
Are the cups fetal or maternal in origin?
Fetal
From what day is eCG produced?
35-40
What produce progesterone until the placenta takes over?
Accessory CLs
After which day can pseudopregnancy occur?
Day 40 - fetus dies but cups still there
What are equilin and equilenin?
Oestrogen-type products
Which part of the uterus contracts?
At the base of a horn
Which horn contracts compared the last year?
The opposite
What happens to the embryo when the uterus contracts?
Doesn’t implant but stops moving
By which day does the placenta form microvilli?
40
How many layers does the horse placenta have?
6
Where does the placenta spread?
Down the fallopian tubes
Why is colostrum compulsory in the horse?
Thick placenta so large molecules can’t cross
After what day can you feel pregnancy by palpation?
Day 20
At what day do you do the first scan to check for no twins?
16 days
At what day do you do the second scan to check yolk scan and see heart?
28-30 days
At what day do you do the third scan?
40 days
After what day are they unlikely to abort?
40 days
At what day is the last scan for sexing?
60 days
If economic constraints, when should you do the one scan?
26-30 days to see asynchronous twins
What do you test for in a blood test for pregnancy?
eCG from day 40-120
Why does eCG not guarantee she is in foal?
May just have cups
What % of twins pregnancies will abort both?
70%
If it is too late to pop a twin and they have fallen over pelvic brim, what can you do?
Inject KCl into heart through abdomen
What is chance of one going to term if using KCl?
40%
How do you determine sex?
Genital tubercle location - tail bail is filly, behind umbilicus is colt
At what gestation is fetal activity greatest?
3-4 months
Where do you see fetal movement on the mare?
Lower flank
What does presentation mean?
Where head is relative to exit eg cranial, caudal
What does position mean?
Where backbone is relative to the mare
What does posture mean?
What extremities are doing
Why will taking milk samples not predispose to running milk?
Because this is caused by muscular sphincter
What can you measure in the milk within 24/48 hours of birth?
Calcium increase and Na/K cross
What is progesterone like in mid-gestation?
Low - will abort if high
What does oestrone sulphate show?
A live foal, but it may not be normal
What produces oestrone sulphate?
Fetal gonads
Where can you measure oestrone sulphate?
Urine- cheaper
How long before term should you use to foaling premises?
6 weeks
Why should you move to foaling premises early?
To build up antibodies
How long before term should you flu and tet?
4 weeks
What should nursery paddocks be like?
Small with rounded corners
How long should foaling box be?
Double the length of the mare
What kind of straw should you use in foaling units?
Wheat - no spiky bits
Why do you need a sitting up room?
Can put mare off
What are four types of foaling alarms?
Position, heat, sweat, vulval
Where do sweat alarms go?
Across the chest
Where do position alarms go?
On the head collar
Why aren’t position alarms reliable?
Go off when the mare lies down
What’s the problem with vulval monitoring systems?
Expensive
How do vulval monitoring systems work?
Stitched in and go off when vulval lips separate
When should you call the vet during parturition?
If colic signs become permanent with no rest period, or if they best exaggerated with no progress
What is happening during first stage labour?
Myometrial contractions
What is happening during second stage labour?
Abdominal muscle contractions
Why do you see allantoic fluid burst?
Placenta bursts at cervix
What shows the start of second stage labour?
Allantoic fluid burst
How long does second stage labour last?
20 minutes
What does allantoic fluid contain?
Urine but not faeces
When should client remove Caslicks?
After fluids have burst as mare is usually lying down
If clients can’t how early can vets remove Caslicks?
No more than 1 week
How soon should you see a foot after fluids burst?
5 minutes
How many feet should you see first?
1
Why should you not pull the foal out?
So allantoic fluid can be squeezed from lungs
How quickly should foal become sternal?
2-3 mins
Why does foal go sternal?
Easier to breathe
How long can the cord take to break naturally?
20 minutes
What are two common injuries if mare foals standing up?
Broken ribs or umbilical hernia
How long can third stage labour take?
Two hours or longer
Why should you tie the placenta up?
To avoid mare treading on it so you can examine the whole thing
Which part of placenta should be on the outside?
Smooth, shiny
What has happened if the red side of the placenta is outside?
Must have detached from foal before birth
What is surface area of foal linked to?
Morbidity/mortality
What % of foals weight should placenta be?
10-12%
Which part of placenta is usually left behind?
Tip of non pregnant horn
What does tip of non pregnant horn look like?
Wrinkled, narrower, thinner
What does tip of pregnant horn look like?
Smooth, oedematous
Which part of horn does foetus implant?
Base
What do yolk sac remnants look like?
Hard, yellow
Where are hippomanes found?
Allantoic sac
Where are there no microvilli?
Cervix
Where can you see endometrial cup remnants?
Base of pregnant horn
What usually causes placentitis?
Haematogenous
What can happen to the foal if placentitis?
Hypoxic
Is placentitis usually recurring?
No
What happens to the foal in vaginal infection?
May become infected
Where does vaginal infection come from?
Stallion
How old is a full term foal?
Over 320 days
How old is a dysmature foal?
After 320 days but with signs of prematurity
How old is an aborted foal?
Before 300 days
How old is a premature foal?
300-320 days
What are three signs of a premature foal?
Small, domed forehead, lax legs
What three things should foals be doing by 5 mins?
Lift head, onto brisket, suck reflex
Why can it be hard to see resp rate in very young foals?
Shivering
What should foal be doing after 15 mins?
Onto brisket, attempt to stand
When should the foal stand by?
30-90 mins
What should you treat navel with?
0.5% chlorhexidine
Why do some owners want enemas?
To prevent meconium retention
Which kind of foals normally get meconium retention?
Overdue colts
What should you use for an enema?
Phosphate buffer
What are 5 prenatal “at risk” factors?
Mare history, mare health, gestation length, lactation, vaccination status
What are two neonatal at risk factors?
Low birthweight, dysmature/premature
On which days should vet examine foal?
1,2,3
Where should the foal run when vet enters?
To its mother
Where should you hold a foal?
Base of tail, around head
What happens if you hold a foal too long?
Plays dead
Why should you check mucous membranes on day 1?
Haemolytic diseases
Which vaccination is given to foals?
Tetanus anti toxin
Why is tetanus antitoxin not always necessary?
Colostral immunity usually enough
Which foals get prophylactic antibiotics?
High risk
Which blood samples do you take on day 2?
Routine haematology and serum protein
What blood level must be checked for insurance?
IgG level
How much IgG transfer is through the placenta?
None
What do you do if not enough IgG?
Give serum sample
What does high MCV suggest?
Dysmaturity
What should neutrophil:lymphocyte ratio be?
2:1
What does neutrophil:lymphocyte ratio other than 1 suggest?
Dysmature
What do plasma fibrinogen and serum amyloid A show?
Inflammation
Why is serum amyloid A better to show inflammation?
Fibrinogen is slower to rise
From what age are autogenous IgG produced?
2 weeks
When in gestation is colostrum produced?
Last 2-4 weeks gestation
What influences colostrum production?
Hormones
How much colostrum does a mare produce?
1.5-2 litres
What Igs are in colostrum?
IgG, IgA, IgM
What other 3 substances does colostrum contain?
Local protective substances, complement, lactoferrin
How does sucking affect IgG uptake?
Increases
By what mechanism is colostrum absorbed?
Pinocytosis
At what time is colostrum uptake maximal?
8 hours
When does colostral uptake end?
36 hours
At what age does serum IgG levels peak?
18 hours
What serum level is partial FPT?
2-4g/L
What level is total FPT?
Less than 2g/L
What is FPT prevalence?
3-25%
Why should you only use equine colostrum?
Avoid anaphylaxis
What can you insure for on day 3?
Mortality
Which kind of plasma is best?
Fresh
What three characteristics should a plasma donor have?
No disease history eg neonatal isoerythrolysis, negative for RBC isoantibodies, vaccinated 4 weeks previously
