Horses 1 Flashcards
(100 cards)
1
Q
What are 4 important factors to consider and 6 things involved with breeding exam
A
Factors to consider - Value of the mare - Purpose of the examination (insurance, pre-breeding check, infertility) - Duration of infertility - Requests of referring veterinarian What is involved 1. History 2. General physical exam 3. Species reproductive exam 4. Special procedures 5. Blood samples 6. Plan of action
2
Q
What are important parts of the history in breeding exam
A
- Age, Breed, ID
- Nutritional information
- Has the mare been presented to a veterinarian before
- Reproductive status
○ Pregnant (in foal)
○ Foal at food (wet mare)
○ Not pregnant - never been bred (maiden) or possible barren - Vaccination status (individual and herd)
- Previous breeding records, if available -> teasing records
- Previous general health problems
- Foaling history
- Breeding history
- History of reproductive problems -> abortions, retained foetal membranes, assisted delivery, dystocia
- Take note of last reproductive event - IMPORTANT
3
Q
What is important to do after taking history for breeding exam
A
- After taking history outline diagnostic approach to the owner
○ Types of procedures
○ Cost
○ Time when results are available
4
Q
Within the special reproductive exam what is involved with the external exam
A
○ Note any discharge on vulva and tail (more common on the tail
○ Determine perineal structures: anus, perineal body and vulva should be in a vertical line
○ Vulva should be below ischeal arch
○ Parting of vulva lips should not lead to air being sucked into the vagina -> need to create a seal
○ Take clitoral swabs, if needed -> before rectal examination contaminates the area
○ Udder
§ Symmetry, activity (lactating or dry), fibrosis, acute inflammation, ticks
5
Q
Special reproductive exam what are the 2 main internal exam diagnostics
A
1) rectal exam - need to tule out pregnancy
2) vaginal exam - second as cannot do while pregnant - lead to abortion
6
Q
Rectal exam describe what exam
A
§ Examine boney pelvis, ovaries, uterus and cervix by palpation and ultrasonography
§ Ovaries
□ Size, presence of ovulation fossa - make sure ovary not a faecal ball
□ Size, wall thickness and tension of follicles
□ Presence of luteal tissue (ultrasonography) - cannot feel CL in horse (unlike cows)
§ Uterus
□ Diameter
□ Tone and wall thickness
□ Contents (air, fluid, cysts, pregnancy!)
§ Cervix
□ Tone, diameter -> better checked in vaginal exam
§ Broad ligaments - checked for haematomas
§ Pelvic cavity
□ Presence of obstruction
7
Q
Rectal exam what findings correlate with uterine infection and pregnancy
A
§ Big CL and uterine oedema -> uterine infection
§ No CL and uterine oedema -> pregnancy
8
Q
Vaginal exam how to prepare and what to perform
A
§ Clean and dry perineum well § Use sterile glove and sterile lube § Manual exam § Speculum exam § Endometrial swabs - cytology - culture
9
Q
How to use endometrial swabs
A
□ Guard swab with hand
□ Use double-guarded swab
1. While advancing hand, note integrity and tone of vestibulo-vaginal sphincter and cervix
2. Take two swabs (one for culture (first to prevent contamination) and one for cytology)
3. Swab for cytology should be well moistened in the uterus (red tinge is fine)
4. Roll out cytology swab on glass slide and let air-dry
5. Stain with suitable stain
10
Q
Endometrial swabs cytology and culture what evaluate
A
□ Cytology
® Evaluate for presence of:
◊ Leukocytes
} (neutrophils - phagocytosis of bacteria should be notes
} Eosinophils - indication for pneumo- or urometra or fungal endometritis
◊ Endometrial cells
◊ Bacteria - morphology indicative of identity
◊ Fungal organisms - special stains warranted
® Diagnosis of endometritis if ratio between neutrophils and endometrial cells is > 1:10
□ Culture
® If clear cytology then don’t worry about sending in culture - dispose of
® If not clear cytology - then send away
11
Q
What occurs if find vagina full or urine
A
not good
- Need to give urethral extension to prevent this therefore need to do a endometrial biopsy
12
Q
Endometrial biopsy when should be obtained and how
A
- Should be obtained from all mares
○ That are valuable
○ That have been diagnosed with chronic endometritis
○ Where no specific cause of infertility can be found
○ That require expensive treatment: rectovaginal fistula repair, urethral extension - Induce biopsy punch manually into uterus, then move hand in rectum and push tissue into jaw of punch
13
Q
What blood samples can take while evaluating fertility
A
- Serum samples for AB tests
○ EG - EVA and EIA -> common
○ Progesterone, eCG, oestrone sulphate - Heparin sample: karyotyping -> for intersex horses so if already had a foal then no
- Plasma sample: inhibin, testosterone -> diagnosis of granulosa cell tumor (GCT)
14
Q
When should endometrial samples be taken and what beware of
A
controversy
- DIOESTRUS after day 5
○ Clear of fluid and bacteria
○ Embryo is present
○ After day 5 for
Beware
- Uterus is very susceptible to infection in dioestrus
- Potential risk of introducing an infection
- Therefore luteolysis HAS TO BE INDUCED by application of PGF2alpha which can only be done after day 5 of the cycle
15
Q
what is important about interpretation of results from breeding exam
A
- Only comment of BREEDING SOUNDESS NOT fertility
- Breeding soundness certificate describes the mare’s chances to fall pregnant
- Determine if tubular or endocrine disorder and if it can be treated
- Discuss treatment plan and how success will be determined
16
Q
What maintains pregnancy of horses and sources
A
- Maintaining adequate levels of progestogens to maintain pregnancy to term
Sources of progestagens- Corpus luteum
- Placenta
17
Q
What occurs with the equine source of progestagens
A
- The primary CL is the main progesterone horse in the equine pregnancy until about day 40 of gestation
○ Uterine progesterone - The weight of the embryonic cups increases rapidly over the first 3 weeks
- The production of ecG (produced by the cups) is closely related to the weight of the endometrial cups
- ecG initially stimulates the primary CL to produce more progesterone
○ ecG is LH-like there results in luteinization of the follicles
○ FSH-like action in other species - High circulatory ecG concentrations then lead to the luteinisation of more follicles resulting in accessory CL
○ At this point the pregnancy is considered more safe - After day 100 the placenta takes over the role for the main production of progesterone (mainly other progestagens)
○ Now considered placental progesterone -> not actually high at this point
○ Equine placenta progestagens -> 5-alpa pregnanes -> main production from the placenta
§ THEREFORE total progestagens is measured not just progesterone as they will be low while total is high
18
Q
Pregnancy loss and return to oestrus what is important at what days
A
- Termination of pregnancy >34 to 37 days gestation (induced or natural) may not result in return to oestrus
- Persistence of endometrial cups may delay return to regular cycles for 3 to 4 months (the cups continue to function and produce eCG; they survive until the time of their normal demise)
○ No foal heat and doesn’t come back into heat
○ Diagnosing -> hysteroscopy
19
Q
Artificial/supplemental light why used, and how to achieve
A
- Used to induce oestrus earlier in season
- Required minimum of 60 days of stimulation (16 hours/per day) until well into transition (may need 90 days to result in ovulation)
- Light has to sufficiently light whole area
- Maintain under lights until diagnosed safely in foal
- Same effects described with 1 hour of light applied exactly 9.5 hours after sunset
Equilume - Mare out in the field with light shining into one eye, attached to the face mask
- Need to ensure the light doesn’t move alignment or break -> labour intensive
20
Q
Oestrus cycle average duration, standing heat, ovulation and dioestrus
A
- Also have average oestrus cycle of 21 days
- In standing heat for up to a week (4-8 days)
- Ovulation occurs 1-2 BEFORE END of oestrus
- Duration of dioestrus is usually 14-16 days
21
Q
Suppression of oestrus when use and what use
A
- Generally in the horse racing, competition environment
1. Progestagen :eg. Oral regumate (once per day), longacting injectable
2. GnRH vaccines’ follicular activity might not return -> should return after a few years as antibodies decrease
○ If never return -> problem!
22
Q
Prostaglandin F2alpha what leads to and why wounldn’t this occur
A
- Luteolysis achieved by single dose
- Standing oestrus after 3 to 6 days
UNLESS
○ Mare not in luteal phase (anoestrus, silent oestrus, transitional oestrus >35d pregnant)
○ In dioestrus, but less than 5 days ago
○ May take longer to come into heat if small/atretc follicles
§ Depends on where the horse is on its follicular waves, small follicles -> larger -> atresia (repeat)
Granulosa (theca) cell tumor (GTCT)
23
Q
Combines oestrogen-progesterone treatment what are the 2 steps and who occurs
A
- IM injection of 150mg progesterone and 10mg of oestradiol in oil for 10 days
- PGF2alpha is given on day 10 (so inseminate 8 days after IM injection)
- Progesterone simulates dioestrus, small amounts of oestradiol suppress growth of small follicles (follicular wave activity)
○ Prevent the follicular wave activity problem for prostaglandin by itself
- At time of withdrawal all mares start with new follicular wave
- At start of treatment
○ Mares in heat: ovulate in first few days of treatment
○ Mares in early mid-dioestrus: will have responsive CL
Mares in late dioestrus: will have undergone spontaneous luteolysis
24
Q
Induction of ovulation when used and fertility
A
- Accurately time OV in mares scheduled for breeding AI
- Part of synchronisation program
- Means of interrupting transitional oestrus - unsure
- Induced OV assumed to be fertile as spontaneous one
25
Human Chorionic gonadotropin hCG how produced, function what occurs and when fails
- Produced by the trophoblast cells of the human embryo placenta
- LH-like function -> luteotropic -> keeps the corpus luteum around
- Results in antibody production (probably don't interfere with action)
- If given at right time (35mm follicle, some oedema) 85% of mare ovulate between 36 and 42 hours
- Might not work in transition when lack of LH receptors
○ Need sufficient oestrogen to produce LH receptors
26
GnRH analogues most common one, when use and what is important to remember
- Most commonly used deslorelin (Ovuplant)
- Ovulation between 42 to 48 hours if given as soon as largest follicle is 30mm
- Implant should be removed to prevent downregulation of GnRH receptors (commonly placed in mucosa of labia)
○ If downregulated will take longer to get back into heat if conception is not successful
- More expensive than hCG
27
What is important in terms of the timing of ovulation induction and when to reexamine after induction
- Trade-off between sperm longevity vs uterine clearance of bacteria, debris introduced by AI
- Ideally to be done at time of insemination/breeding (except frozen semen)
- If semen stored for more than 30 hours, induce OV 24 hours before AI
When to reexamine
- 48 hours later, if induced early enough
- Playing the odds: 80% of mares follow the book
- Rest might not ovulate at all that cycle
- In that case discuss if more semen is to be invested (wasted?)
28
What are the 3 main tools of determine timing for breeding
1. Teasing
2. Rectal exam: palpation and ultrasound
3. Vaginal exam - not on all
29
Teasing the mare what are important principles
- Most important management tool for breeders (esp. thoroughbred studs)
- Teasing records very important to veterinarian
- Preferably done by same person every day
- Mares must be teased regularly (ideally daily) from 3 day post-partum until 60 days pregnant
- Teasing cute/wall is ideal (open front and back)
- Stallion starts at head and is then allowed to move backwards and ideally rest head on croup
- Mares have individual teasing patterns
30
What are some signs that a mare is ready to be bred
- Ovulatory follicle: usually +/-mm of same size each cycle; can be large individual differences between mares
○ Generally don't look for on commercial farms as just wait till she is ready to be induced
- Increasing oedema
Cervix relaxes in oestrus, open until ovulation, then it closes
31
Natural breeding problems
○ Stallion can only breed limited number of mares
○ Mare and stallion have to be in same location
○ Risk of diseases, injuries
○ Difficult to assess semen quality (dismount sample - can get concertation, morphology but NOT VOLUME)
§ Don't know how much went into the mare
32
Artifical insemination what are 6 advantages over natural service
1. More mares can be bred to single stallion
○ 500 - 800 per year
2. Mare and stallion do not have to be in same location
3. Limiting transmission of venereal diseases
4. In case of incompatibility (size, temperament, physical, disability) breeding still possible
5. Minimum contamination breeding technique possible
6. Stallions semen quality can be monitored
33
Artifical insemination how to collect, AI dose and when to AI
How to collect
- Different vagina models
- May need phantom mare/ teasing mare
AI dose
- 500 million progressively motile sperm
- Sperm count (haemocytometre)
- Motility assessment (heated phase contrast microscope) done at 37 degrees
When to AI
- Semen is best kept in the mare's uterus
- Shipping container good for transport
- BUT semen should be inseminated as quickly as possible
- No reason to split dose over two days
34
Raw semen what is good about it and what important when done with AI
○ Minimize injuries
○ Assess semen quality
○ Breed multiple mares from same ejaculate
Raw semen with AI
○ "dirtiest" of all AI methods
○ Risk of iatrogenic infection especially when done in early or later oestrus
○ AI dose not dilate cervix as stallions penis would
○ Deposit desired dose into uterus w/in 30min
35
Fresh extended semen when use, how extended and how long last
○ When number of mares are to be inseminated with same ejaculate
○ Integral part of "minimal contamination breeding technique" for mares susceptible to endometritis
○ Collected semen extended at 1 part semen to 4 parts extender (at least 1:2)
○ Extend sample to a concentration of 25-50 million/ml
○ Centrifugation might be necessary
○ Should be used within 3 hours at room temperature
36
Cool extended semen goal, how occurs and success
○ Goal: breed once per cycle
○ Observe stallion collection schedule
○ Extended semen cooled to 5 degrees
○ Colling rate critical (1 degree/3mins)
○ If manual: extender and semen at 37 degrees placed in beaker with 37 degrees water, add ice
○ Commercially available shipping containers cool at ideal rate
Success with cooled extended semen
○ Varies by stallion and individual farm management
○ Not all stallions can have semen successfully shipped
○ With best management and semen from a fertile stallion, equal to other methods:
§ 75+% first service conception
37
What are the 2 main important stallion variations within artifical insemination
1) fertilisation capability of sperm - up to 72 hours in storage, some earlier - should be tested before chilled, extenders can be used
2) number of AI doses/ejaculate also variable - if unknown do not plan more than 5-10 insemination in 2 days
38
What are the 3 events of puerperium
1. Uterine involution
2. Shedding bacteria
3. Resuming regular cyclic ovarian activity
39
Foal heat when present, when end, and what is the trade off
Foal heat
- Onset usually 6 to 9 days post foaling (5 to 12 days normal)
- Ends with first ovulation post-partum
- Interval becomes shorter later in season
- Higher early embryonic death rate if breed in foal heat (if OV before D10)
Trade-off between getting mare in foal as early as possible and ensuring successful outcome of pregnancy
- If breed in foal heat and successful actually gaining time (foal born earlier than last one)
- HOWEVER if breed foal heat but not successful then have to wait another 30 days to cycle again
○ Falling behind with schedule as if didn't breed in foal heat would have short cycled her and then gotten pregnant earlier
WORSE if breed foal heat and successful but then LOSE pregnancy then you can be quite a lot of days behind
40
What are 2 situations to breed and 3 when don't breed
BREED
- Normal parturition and puerperium
- Ovulation > D 10 post-partum
DON'T BREED
- Abnormal parturition and/or puerperium
- Ovulation < D10 post-partum (short cycle instead)
- Don't induce ovulation
○ Why not induce her on day 10? -> later she ovulates the more time for puerperium so successful pregnancy
○ THEREFORE -> not ideal to breed with frozen semen or heavily booked stallions as need to induce for these
41
A mare with a history of fluid after breeding what is the plan for next breeding
○ Order semen
○ AI the next day
○ Fluid in uterus flush out immediately prior to breeding (AI within 30min
§ So by the time the uterus has an inflammatory reaction then the sperm has migrated into oviduct
○ OV induction post-breeding
§ When do you examine her next -> 4-6 hours later up to 24 hours later
□ Would not have ovulated at this point
○ Treatment the next day
§ Depending on echogenicity, volume and cytology sample
42
When would you use a minimal contamination technique and the objective
- Objective: minimise chances of uterine infections
- Indications:
○ Stallions that are known to shed bacterial pathogen
○ Mares that have history of recurrent uterine infections (susceptible mares) cannot rid themselves of bacteria in time for embryo arrival (day 5)
43
What to do with semen in a minimal contamination technique
- Semen should be diluted with extender (at least 1:2, ideally 1:4)
- Type of sperm
○ Chilled-shipped or fresh -> doesn't matter however fresh have another 24 hours (don't have to ship) however if far away the only way is to do chilled-shipped
44
What to do with the mare with a minimal contamination technique
- Mares should only be bred once per cycle
- As long as before ovulation as possible (48h)
- Uterine flushes if fluid detected in uterus (always until returning fluid is clear)
○ Can flush until 2 to 3 days post-ovulation, if necessary
- Oxytocin (10-20 IU) should be given at end of each flush and 4 h after breeding (at this point semen safe in oviduct)
§ If give too much then may affect corpus luteum and decrease progesterone production (not good for pregnancy)
○ Systemic antibiotic therapy until 3 days post ovulation -
- DILATE CERVIX after AI
- If pneumovagina is present temporary Caslicks can be done daily and permanently after end of treatment
45
Frozen semen advantages and disadvantages
○ Semen available without regard to stallion's racing/show schedule
○ Can be shipped worldwide
○ Even decreased stallion's semen can be used for breeding
○ Semen can be collected any time of year
Dis
- management more expensive
46
Success with frozen semen and ideal insemination time
- Varies by stallion, timing of mare, frequency of palpation, expertise
- Usually averages out to 30-35%/cycle
- Best management coupled with semen from a fertile stallion can yield results, equivalent to other methods (fresh, chilled): 75% + percent first service conception rate
- Increased success if mare is of ideal breeding health
- Mares that conceive with frozen semen mostly do so in cycle 1 or 2
○ If not by 3rd cycle, recommend switching to fresh or chilled (often successful)
Ideal insemination time: 12 hours prior to 6 hours after ovulation
47
What are the steps and the days which they are done for setting up AI with ovulation induction
Day 1: 8 pm (0 hours): deslorelin - induce ovulation (follicle between 30-35mm) - CAN'T HAVE LH SURGE
Day 2 (- 24 hours): scan mare to ensure she does not look like she will ovulate on her own
Day 3: 8am (36 hours): scan mare to ensure she has not ovulated - if she has just inseminate
Day 3: 2pm (42 hours): inseminate
Day 3: 8pm (48 hours): confirm ovulation
IF she has NOT ovulated
- Owner makes decision if that cycle is to be skipped or mare must be scanned every 6 hours to be inseminated again once ovulation is detected
- Mare should not be AI'd again until at least 18 hours after 1st AI (inflammatory uterine reaction)
○ shouldn't inseminate until the next morning at 8am
48
The regumate effect what occurs, problem, when should give
- Common practice to treat mares with hx. Of pregnancy loss with exogenous P4 (Regumate)
- Primary luteal insufficiency HAS NEVER BEEN SCIENTIFICALLY PROVEN
- Commonly given when P4 levels are low
The problem
- If mare loses pregnancy FOR ANY reason it will be blamed on the fact that P4 was not given
When should it be given???
- Before maternal recognition, start progesterone d5-10
49
Should we keep using regumate even if may not help and when do horses actually need it
Should we keep on Regumate
- No right answer -> if say she doesn't need it and then lose pregnancy -> YOU ARE AT FAULT
- Often progesterone decreases because losing pregnancy - regumate won't prevent this
When really need it??
- Anything that might cause luteolysis
○ Endotoxemia
○ High plasma cortisol levels
○ Failure of conceptus to signal maternal recognition of pregnancy
- May need to keep on until day 42-45 until secondary CL comes into play or just until the disease has been resolved
- If on regumate then can test for progesterone levels to see whether they are stable at high level
50
Where is semen deposited, fertilisation occurs and transport of conceptus where
- Sperm deposited into uterus
- Fertilization in ampulla of oviduct
- Transport of conceptus into uterus (5 to 6 days after OV)
- Unfertilized ova remain in oviduct
51
When does fixation and implantation occur and what important about these
- Fixation occurs at D 16/17
○ Stuck at the base of the horn
- Implantation starts around D 35
○ When placentation starts -> attaches through endometrium
- Nutrition through histiotroph (uterine milk) and yolk sac
- Embryo is very vulnerable in this phase (EED)
52
Early embryonic death (EED) fertiization therefore EED rate, when most option and causes
- Fertilization rate >90% (EED 5 to 25%)
- Most often before D 11(before detection)
- Causes:
○ Intrinsic factors (endometritis, endometriosis (degenerative disease of connective tissue), P4 deficiency, nutrition)
○ Extrinsic factors (stress, heat)
○ Embryonic factors (chromosomal abnormalities)
53
What is the typical schedule for equine pregnancy scanning
Day 14 post ovulation (NOT INSEMINATION) - pregnancy & twin identification - HAS TO BE BEFORE DAY 16
Day 25 - 28 post ovulation - assess foetal viability (heart beat)
Day 40 post ovulation - confirm pregnancy (stud fee is usually due around this time)
Day 60 - 70 post ovulation - foetal sexing -> visualise the genital tubercle position
○ Only done by equine vets and need a 100% success rate as based on thousands of dollars
Day 150 - transabdominally sexing - external genitalia, penis, prepuce, teats, clitoris - not commonly done
54
Twin management how do twins generally result
○ 50% unilateral ovulations -> harder to see the 2 different CLs if fix on same horn
○ Asynchronous OV (1-4days) result in size difference up to 4mm of conceptuses
§ May then miss the small conceptus then miss twins - BAD
○ 70% unilateral fixation
NO EXCUSE FOR MISSING TWINS
○ Always scan both ovaries!!!
§ If only see one conceptus but 2 CLs - recheck 2 days later
55
What are conception rates with ovulation
1. Single ovulations - 80%
○ 70% pregnancy rate, 30% empty
2. Double ovulation - 20%
○ 10% empty
○ 90% pregnant - BETTER THAN SINGLE OVULATION but 50% have twins (good management not an issue)
§ Unilateral fixation 70% - 83% will reduce by themselves
§ Bilateral fixation 30% - 100% will still be bilateral twins -> will not reduce
56
Twin reduction options after unilateral fixation
○ 83% should reduce to singleton pregnancy
○ Reeaxmine D 33-34
○ Options
§ PGF2alpa (esp early in season)
§ Transvaginal, us-guided needle aspiration (50% success that one goes to terms)
§ Manual crushing (not very successful)
57
Twin reduction options after fixation (bilateral)
○ Spontaneous reduction extremely unlikely
○ Crush immediately
○ Might still lose both
○ Keep teasing mare
58
twin reduction after day 40 options
○ Season is lost
○ Owner's decision - inform about risks (dystocia, premature foals, non-viable/athletic foals)
§ Abort -> give multiple injections of PGF2alpha
○ If he wants to take on risk:
§ Decapitation can be done later
§ Modified wait and see approach
□ Mare aborts because of sudden drop in progestagens when one foetus dies; both aborted (usually one still alive at time of abortion but non-viable)
59
What are the 2 main reasons for premature udder development
1. Twins - one has aborted
| 2. Placentitis
60
Placentitis signs, how occurs and diagnosis
- Signs: premature udder development and/or vaginal discharge (possibly fever)
- Usually ascending (Sc.equi sp zooepidemicus, E.coli, Klebsiella pneumoniae)
- Impending abortion threat believed to be due to decrease in placental progestagens
- Diagnosis:
○ Transrectal ultrasound (transabdominal if haematogenous)
○ Measure CTUP (combined thickness of uterus and placenta)
61
Placentitis treatment
○ Antibiotics (penicillin/gentamycin, trimethoprim sulfamethoxazole
○ Exogenous progesterone
○ Flunixin meglumine
○ Pentoxifylline
○ CHECK FETAL VIABILITY REGULARLY (weekly) - AS WELL WITH TWINS
62
When does most parturition occur and signs for readiness for birth
Parturition
- Most mares foal between sunset and midnight ---> foal watch
○ Need to provide a quiet environment but still need to check on the mares regularly -> balance possible video surveillance
- Endocrinology not well studied in the horse
Readiness for birth
- 4 weeks -> udder size ↑
- 2 weeks -> sacro-sciatic ligaments reflex
- 2-3 days -> waxing
- 1-2 days -> milk Ca ↑
63
Induction of parturition indicators, risk and what are the 2 main protocols
- Very few indications -> Prepubic tendon rupture
- Inform owner about risks -> risky for both mare and mainly foal
Two protocols
1. Normal protocol
a. Give 10 IU of oxytocin IV
b. If water doesn't break within 40min: vaginal exam
c. If straining for 10min without water breaking: incise chorioallantois
d. If straining for 10min after water has broken: check for malpresentation/-position - in stage II labour
2. Modified protocol
a. Give 2.5 IU oxytocin IV
b. If mare progresses to foal: RFB was in place
c. If mare does NOT progress: postpone induction
Helps prevent premature foals being born
64
What are the clinical signs and how long does stage I last
- Up to 12 hours (normally 1-4 hours)
- Uterine contractions, positioning of foetus
- Restlessness
- Frequent urination
- Defecation
- Sweating
- Laying down/rolling
65
What are the clinical signs and how long does stage II last
- 5-20min
- Foetal expulsion
- Starts with rupture of chorioallantois (breaking her water)
- Abdominal contractions, mare becomes recumbent
- Rapid delivery (if >60min foal likely to die)
○ Once complication has occurred, call vet within 20mins, examine the horse, then possibly have to refer can take a while to get to clinic ->
66
What are the signs of stage III and time
- Expulsion of membranes
○ Can be kept to provide information on problems with the foal
- Usually delivered within 30 to 90 min after end of stage II
- Retained when FM not released by 4-6h post-partum
67
Dystocia how common but what is the problem
- Rare (1.5 to 2.5% of parturition)
- BUT: mares birth canal is easily traumatized
○ Uterus damaged, decrease fertility in the duture
- AND: foal are likely to die, if they are not delivered within 60min of chorioallantoic rupture
ALWAYS BE CLEAN, GENTLY AND USE LOTS OF LUBE
68
Dystocia how does it general present and initla treatment
- How presents
○ Foals tend to get stuck with their shoulders (hip lock is rare)
○ Abnormal presentation, position, posture of legs or neck
§ CANNOT be delivered backwards
- Initial treatment
○ Get mare up and walking -> try to stop as many contractions
○ Epidural should be given if manipulation is not quick
○ Clenbuterol injection can help to relax uterus
69
Foetotomy when used, how used
- Usually one or two cuts are sufficient
○ Goldern cut -> wire in a loop behind the shoulder (far back) and cut down over one shoulder and neck
- Mare has to be restrained and sedated
- Administer epidural
- Be very clean and careful
70
Red bag what is it and what need to do
- True emergency!
- Don't wait to get there, tell someone to take action NOW
- --> cut chorioallantois and delivery foal ASAP
○ ANY SHARP OBJECT
○ Need to monitor the foal
§ Dummy foal -> hypoxic, slow in development, not suckling enough, not getting enough nutrients or antibodies
71
Foetal membranes what to do with them
- Collect them
- Weight them
○ Too heavy possibly have oedema
- Lay them out and check structure
72
Retained foetal membranes what to do to remove and then treatment afterwards
- Can try 10IU oxytocin every 45min
- If no progress within 2 hours, start treatment
---> septic metritis happens very fast
---> life-threatening consequences (eg. Laminitis, septicaemia, toxic shock and death)
- Treatment
1. Broad-spectrum AB (penicillin/Gentamycin)
2. Flunixin meglumine (anti-toxic dose 0.25 mg/kg, if concerns for renal function)
3. Oxytocin 10 IU -> more oxytocin -> if give too much could contract uterus enough to prevent removal of membranes
4. IV fluids
5. Go into vaginal and gently twist the membranes while other hand in rectally and try to loosen the attachments
§ Tie off the membranes to ensure the mare doesn't step on them and break off the weight (want to weigh down)
73
Peripartal haemorrhage when occur, what artery involved, results
- Can occur pre-, intra- or post-partum
- Any large uterine artery can be affected (usually middle uterine artery)
- Can be fatal very quickly
- If bleeding into broad-ligament: haematoma might build up sufficient pressure to close off vessel and stop bleeding
- --> don't move mare (confine in small area)
74
Puerperium exam when performed and what check for
- Post-partum exam <24 hours post-partum should be routine (mare, foal and FM)
- Caslicks should be closed 1 to 4 h post-partum
- Check for
○ Vaginal/vestibular lacerations
○ Perineal lacerations (leave III degree for 6-8 weeks)
○ Cervical lacerations
○ Uterine rupture (rare sequalae of dystocia)
75
Vestibular/vaginal lacerations treatment
- If more than mucosa is involved risk for bacterial infections and adhesions
--> treat like any other deep wound
○ Systemic antibiotics
Topical antibiotic cream (bovine mastitis)
76
What are the 4 main indications of castration
- allow easier management and to control breeding in horses -> MAIN ONE
○ associated with a modification of behaviour.
- Testicular torsion
- Inguinal hernia
- Testicular pathology
77
Immunological castration how occurs, what used for and why not used much
- Vaccine against GnRH equity
- Only registered for use in mares NOT COLTS/STALLIONS
- 10% of male horses -> became permanently infertile, doesn't change behaviour of all male horses
Should not use in animals intended for breeding in the fertility
78
What should you do before you perform a castration
- Identify horse -> brands, microchip
- Clinical examine -> physical examination
- Check both testes and that they have descended
- Client consent -> sign a consent form
- Insured? History or hernia?
- Tetanus vaccination up to date
79
What are the 2 techniques for castration and how performed
- May be performed standing or under general anaesthesia
Refers to how the parietal tunic is treated at the time of surgery
- Open - parietal tunic is incised and left open
- Closed - structures are ligated without opening parietal tunic
- Semi-closed - tunic incised to remove structures then later closed
80
Surgicial techniques for castration what is important
○ Asepsis - Sterile instruments -> sterile gloves, emasculator, drapes
○ Skin incisions adequate length for good post-op drainage
○ Adequate removal of tunic - helps prevent post-operative swelling
○ Good haemostasis
- No clipping needed just surgical scrub of scrotum and surrounding area
81
Standing castration advantage and disadvantage and what needs to be done
- May have a cost advantage, yet complications more frequent
○ Quicker -> don't have to wait for the horse to wake up from general anaesthetic
- Quiet colts whose genitals can be palpated without sedation usually are the safest candidates.
- Emasculate the cord -> crush the spermatic cord to control bleeding
- Primary closure not possible
- In preparation, the horse is sedated, usually a nose twitch is applied and 5-10 ml local anaesthetic is infiltrated subcutaneously on either side of the median raphae, 15-25 ml directly into each testis +/- 10-20 ml proximal to the testes into the spermatic cord.
82
Castration under general anaesthesia technique
○ Needs a short GA
○ Pre-op: tetanus prophylaxis, PBZ, antibiotics (not as common - not needed for sterile procedure)
§ Antibiotics -> give 30-60mins before surgery and for up to a few days
○ IV catheter
○ Positioning - surgeon preference
§ Ideally grass clean area
○ Ligate vessels or crush (emasculate) only?
- Close tunic?
- Skin closure? -> only really done in a surgical facility
83
What are the first 6 steps up to cutting the testes in castration
1. Grasp testis from cranial aspect and make longitudinal skin incision in VENTRAL aspect of scrotum immediately parallel to midline raphae
2. Exteriorize the testis within the parietal tunic - squeeze
3. For a closed technique -> the parietal tunic is not incised, cord if emasculated (crushed) and can be ligated if aseptic conditions
- For an open technique -> the parietal tunic is incised, identify testicle, vas deferens -> hold the cord and vas deferens and use your fingers to bluntly punch a hole in the tissue behind them
4. Grasp and cut the attachment of the tunic to the tail of the epididymis
5. Emasculate (if have cutter position nut to nut) the cord for 2-3mins (relax the vessels don't stretch)
6. Cut off and discard testis
84
Steps 6-12 in castration from cutting off the testes
6. Cut off and discard testis
7. Under aseptic conditions a ligature may be placed around the cord as an additional haemostasis precaution
8. Allow the cord to slide within the tunic to within the inguinal canal - watching as disappears to ensure no bleeding
9. Strip the tunic from the surrounding tissue to allow emasculation +/- placement of ligature near the external inguinal ring (if aseptic conditions)
10. A ligature around the tunic effectively closes the tunic and reduces risk of herniation - if septic still
11. Repeat the procedure for both testes then ensure the skin incisions are adequate to allow effective drainage
12. Trim off any tissue that may prolapse out of the wound taking care not to cut any small vessels that can cause nuisance bleeding
85
What are 5 important parts of post-op care for castration
- PBZ for 3-4 days
- Antibiotics - sometimes, in aseptically then not needed
-Clean environment - not dusty
- Confine for initial 12-24 hours then exercise
○ Exercise important to ensure drainage and reduce oedema
- Separated from mares for at least several days
86
What if there is male behaviour yet testes are not palpable or identified with US and castration history is unknown?
1. >18 months - anti-mullerian hormone produced by Sertoli cells
○ Simplest if at the right age
2. < 2 yo or donkey of any age HCG stimulation test
○ Testosterone baseline and 30-120mins after giving HCG -> gelding <40 pg/ml, cryptorchid >100 pg/ml
3. 3 yp Oestrone sulphate
○ Single blood test -> gelding <40 pg/ml, cryptorchid >400 pg/ml
87
Cryptorchid castration what is needed for and main approaches
- DO NOT REMOVE DESCENDED TESTIS IF CANNOT FIND THE RETAINED - need to be identified as cryptochirid and take to facility
- Approaches
○ Inguinal -> generally for inguinal testes
§ Care as large number of vessels in the area
§ The scrotal ligament and vaginal process are located
§ Traction on vaginal process to exteriorize epididymis followed by testis
§ Once testis is exteriorised it is removed as described earlier
§ Attempt to suture external inguinal ring +/- primary closure of skin
○ Parainguinal
○ Paramedian
○ Caudal midline
- GA or standing
○ Laparoscopy -> more widely used as provides good access to abdominal cavity -> better for intra-abdominal testes
88
Intra-abdominal testes what is the best technique and why
```
- Laparoscopy has advantages
○ GA or standing
○ Minimally invasive technique
○ Great visualisation
○ Early return to exercise
```
89
What are the 6 main complications to castration from easrlies to latest
1) haemorrhage
2) evisceration.herniation
3) prolapse of omentum
4) excessive swelling +/- infection
5) infection
6) ther complications due to surgical errors -> failure to remove testes, lacerations at base of penis
90
Haemorrhage complication for castration, what is excessive, which vessels involved and how to fix
○ What is excessive
§ If dripping more than 1 drop per second or steady stream more than 15 mins
○ Which vessels
§ Most important are testicular artery and vein, as well as blood vessels in cremaster muscle and subcutaneous veins
○ How to fix
§ Sedation, handling, sterile gloves
§ Pack scrotum with gauze/swabs or bandages
§ Apply forceps standing
§ Ligate? Need GA - if keeps bleeding -> need to identify the vessel
§ Has it lost enough blood that does it need fluids or blood transfusion
□ Elevated HR, pale mucous membranes, PCV (first 6 hours after bleeding doesn't reflect)
91
Evisceration/herniation complication after castration what time frame generally occur, what most common and how to fix
○ Uncommon but life-threatening
○ Anytime up to 5-6 days but most common up to 12 hours after surgery
○ Small intestines
○ How to fix
§ Prepare for referral
§ Sedate, confine
§ Sling to protect the small intestines from trauma, infections and from more coming out
□ Can use sling or glad wrap
§ Antibiotics, NSAIDS (Bute = phenylbutazone), insured?
92
Prolapse of omentum and infection as complications of castration how to treat
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Prolapse of omentum
○ Dealt with in the field
○ Trim
○ Confine and monitor
Infection
○ Antibiotics and PBZ (bute)
○ Establish drainage
○ Resect chronic infected tissue "scirrhous cord"
May need to surgically excise the cord tissue that is chronically infected
```
93
Excessive swelling as a complication after castration what most commonly due to and how to treat
```
○ Most common due to:
§ Poor drainage
§ Insufficient exercise
○ Often worse at 4 days
○ Infection
○ NSAIDS
○ How to treat
Use hands and open up old wounds to establish drainage and exercise
```
94
Penile squamous cell carcinoma what caused by, most common in, character, diagnosis and treatment
• Caused by a papilloma virus and exposure to sunlight and smegma
• Tends to be middle aged to older horses
• Can metastases
• Take biopsies and check to metastases (regional lymph nodes)
• Treatment:
○ Superfical lesions - cryotherapy (liquid nitrogen), or chemotherapy (topical 5-FU cream)
○ More extensive lesions -> surgical excision or laser PLUS intralesional chemotherapy (cisplatin
95
What are 12 main differential diagnosis
1. True temporary anoestrus
2. True permanent anoestrus
3. Granulosa (theca) cell tumor (GTCT)
4. Anovulatory haemorrhagic follicle (AHF)
5. Persistence of CL
6. Ovarian haematoma
7. Endometritis
8. Ovarian abscess (RARE)
9. Teratoma
10. Silent oestrus
11. Retention of endometrial cups
12. Transitional oestrus
96
What causes a true temporary anoestrus
- Consider season (winter) -> physiological anoestrus -> want to change
- Systemic disease
- Possible anabolic steroid treatment ----> few trainers will admit to it
- GnRH vaccine used?
○ Few never regained cyclicity -> huge loss of income so not common - need to be sure that NOT BREEDINGING - can never be sure
97
What causes true permanent anoestrus, signs that suggest and treatment options
- Chromosomal abnormality suspected in mares that have never cycled before
- Possible display of masculine behaviour
- Possible obvious external genitalia anomalies
- Karyotyping recommended
- If give FSH and nothing occurs not much that can be done for those ovaries
98
Granulosa theca cell tumours findings, diagnosis, treatment and prognosis
- Findings
○ Large ovary and other ovary very small (inactive) - As tumor secretes inhibin
○ Ovulation fossa obliterated by tumor - helps with diagnostic during vaginal exam
○ Honeycomb/polycystic appearance
- Difficult to diagnose during pregnancy or if bilateral -> ovary normally large
○ Inhibin levels elevated in >90% - used to be used for testing
○ New test: Antimuellerian Hormone (AMH) ↑ -> NOT COMPLETELY DIAGNOSTIC
- Treatment: unilateral ovariectomy
- Prognosis: for breeding soundness: good; might take 6 to 8 weeks for cyclicity to resume
○ Generally doesn't metastasise so can wait and see
99
AHF (anovulatory haemorrhagic follicles) when most commonly occurs,, most common in, develop from
- More common in transitional oestrus -> last or first ovulation
○ Generally only occurs once but hard to predict - annoying when already inseminated
○ BUT can occur again at the same time next season
- More common in older mares
- Develop from anovulatory follicle that fills with blood
100
AHF (anovulatory haemorrhagic follicles) how to differentiate from CH, size, what results in
- Difference to CH: CH (corpus haemorrahgic) has clotted blood - Anticoagulant in follicular fluid prevents clotting
- Size variable (5 to 15cm)
- Will take longer to react to PGF2alpha than regular CL -> longer between oestrus
○ Wait 10 days and give for 2 consecutive days
