Equine repro (ruptured bladder, urolithiasis, pregnant colic, castration, foal medicine) Flashcards
How often should urine outflow from the ureters be seen under xylazine sedation by endoscopy?
Every 20-45 seconds
Ruptured bladder in foals - Age? Why happens? Clinical signs?
1-5do (more common in colts) Excessive pressure during parturition on a distended bladder More common ventral Rare in adults Clinical signs: - depression/off suck - progressive abdominal distension - mild/moderate colic - increased frequency of attempted urination and small volumes passed (dysuria esp stranguria)
Diagnosis of a ruptured bladder in foals?
History and presenting signs Biochemistry and haematology - hyperkalaemia - hypo Na and Cl - dehydration - metabolic acidosis - post renal azotaemia Peritoneal fluid analysis - serum:peritoneal fluid creatinine >1:2 - clear fluid with low SG - may be calcium carbonate crystals Ultrasonography \+/- Radiography and contrast studies
Why must a foal with a ruptured bladder be stabilised before GA? How? Treatment?
Hyperkalaemia can cause fatal arrhythmias - K+ must be <5.5 before induction
Rule our concurrent disorders e.g. sepsis
Fluid therapy
- IV saline/Hartmann’s
- +/- sodium bicarbonate
- calcium boroglucoronate (antagonises the adverse myocardial effects of hyperkalaemia by raising threshold potential)
- insulin/glucose (insulin stimulates activation of Na/K ATPase pumps to get K+ back into cells
Abdominal drainage (slow) - reduce K+ and improve ventilation
BUT AVOID BICARBONATE AND INSULIN IN FOALS - USE 0.9% SALINE WITH 5% GLUCOSE
Oxygen therapy
Antibiotics
Check IgG status
SLow drainage of peritoneal fluid
Then surgical repair via midline laparotomy +/- resection of umbilicus and urachus at same time
Urolithiasis in horses - Which horses? Associations? Types? Diagnosis? Treatment?
Uncommon (usually found in bladder)
Adult, male horses
Cystitis
Urinary tract obstruction
2 types of calcium carbonate):
- type I (more common): spiculated stone, yellow/green
- type II: smooth and white, harder and contain more phosphate
Also sabulous urolithiasis - sludge usually secondary to bladder paralysis
Diagnosis:
- history and presenting signs: haematuria, stranguria, +/- pollakuria, pyuria or incontinence
- clinical exam - rectal exam
- ultrasonography
- endoscopy
Treatment:
- surgical removal: laparotomy/laparoscopy
- electro hydraulic/laser lithotripsy
What is sabulous cystitis?
Secondary problem
Consequence to bladder paralysis or other physical or neurologic disorders interfering with complete bladder emptying
When would a nephrectomy be performed in the horse?
Renal neoplasia
Pyelonephritis non responsive to medical treatment
What do the umbilical arteries and vein and urachus become?
Umbilical arteries - lateral ligaments of the bladder
Umbilical vein - round ligament of the liver
Urachus - round ligament of the bladder
What happens normally to the umbilicus in foals? When to investigate?
Umbilical cord breaks naturally immediately after parturition
Should progressively dry up and disappear over 4-6 weeks
Investigate if moistness >24h, swelling/pain on palpation or if febrile
Patent urachus in foals - Why happens? Signs? What to check? Treatment?
Fails to close spontaneously or can reopen if sepsis occurs
Moisture around umbilicus +/- dripping of urine
Check for concurrent septicaemia/septic arthritis or physitis
Assess IgG status
Medical treatment - antibiotics, topical cauterising agents (concentrated phenol or iodine solution or with silver nitrate applicators)
Often self resolving
Surgical - resection of urachus
Umbilical sepsis - Age when seen? Signs? Diagnosis? Treatment?
First 1-2 weeks of life
Foal depressed & off suck
Swollen, painful umbilicus
Diagnosis: ultrasonography of umbilicus
Treatment:
- assess IgG status & assess for concurrent septicaemia/septic arthritis/physitis
- blood culture, haematology & biochemistry
- systemic antibiotics
- surgical resection if no response to therapy/deterioration
Umbilical hernias in horses - Significance? When is surgical repair needed?
Common congenital defect Most are small and resolve with time Determine size and whether reducible or non reducible Surgical repair required if: - large defect that persists > 6mo - defect enlarges - associated with colic
How old is a colt/stallion and filly/mare?
<4 = colt/filly >4 = stallion/mare
When should testes have descended into scrotum in colts?
Normally descend into inguinal canal at 270-300d gestation so normally present at or shortly after birth
If not, may occur up to 24mo
When does puberty of colts and fillies occur? When is maximal sexual maturity reached in stallions? How long do mares cycle for?
12-24mo
Stallions: Maximal sexual maturity reached at 4-5 years and retained until about 20 years
Mares: Cycling continues for rest of life but fertility may decline
Anatomy of the stallion’s penis?
Photos
How long does spermatogenesis take?
60 days
What affects stallion semen quality?
Testicular size
Testicular efficiency - greater % of testicles that is sperm producing = more sperm
Age - younger stallions produce less sperm and run risk of being overworked, production maintained well after full sexual maturity
Season - long day breeders
Frequency of ejaculations - number of sperm halves after each successive ejaculation
General health/injury
Sperm dose required for natural service and AI? Number of mares mated per day?
Natural service - 500 million motile sperm
AI - 150-500 million motile sperm
Some busy stallions may mate up to 6 mares in a day
Where is swabbed for CEM? What causes it?
Urethra, urethral fossal, penile sheath, pre-ejaculatory fluid if available
Taylorella equigenitalis
Equine Viral Arteritis (EVA) - Main problem? Vaccination?
Causes Abortion Stallions become carriers Notifiable in stallions Blood test before vaccination to prove seronegative Artervac vaccine
Treatment for paraphimosis and priapism of stallion?
Paraphimosis (inability to retract penis into prepuce) - support with some kind of truss, maybe give GA roll on back and gently replace penis in sheath and place purse string sutures across preputial orifice
Priapism (persistent erection without sexual excitement) - surgically corrected by flushing corpus cavernosus with heparinised saline under GA, B2 agonist
What specific conditions to check for with stallions with colic?
Inguinal herniation
Scrotal herniation
Testicular torsion
Advantages of AI?
Can be transported - spreading genetic material
Can be stored even after death
Ejaculates can be divided into smaller doses - more matings
Reduces risk of venereal disease
Reduces post mating endometritis
Can be examined readily
Disadvantages of AI?
Specialist skills needed to collect, process and inseminate semen
Conception rates may not equal natural service
Expensive
Labour intensive
Venereal infection still possible
Not acceptable for thoroughbred authorities
Use of semen after collected from stallion?
Fresh - use within few hours, can use extenders (increase lifespan of sperm, may contain antibiotics to kill pathogens, often milk or egg based)
Chilled - can last up to 48h, mixed with extenders and then slowly cooled to 5C
Frozen - separated into small 0.25-5ml doses, treated with extenders and cryoprotectants, frozen in sealed straws, stored in liquid nitrogen flasks, keep forever, warm to 37C in water bath, dried, unsealed and inseminated just through cervix or into uterine horn on side of ovulation
When to serve mares?
Natural, fresh, chilled - up to 48h before ovulation
Frozen - best as close to ovulation as possible as survival time not as long (up to 12h before or 6h after ovulation)
Pre-parturient problems in the mare?
Colic - foal moving, normal GI colic, colonic infarctions/necrosis, uterine torsion
Overlarge mare - ventral oedema, pre-pubic tendon rupture, hydros hydrallantois/hydramnios
Placentitis
Varicose veins
Orthopaedic disease
Intrapartum problems in the mare?
Dystocia Uterine rupture Uterine tear Cervical tear Perineal tear
Post-parturient problems in the mare?
Colic - uterine cramps, normal GI colic, uterine haemorrhage, colonic torsion, uterine horn inversion, colonic infarctions/necrosis Prolapse - uterus, rectum RFM Metritis Hypocalcaemia Tetanus Cervical tears Perineal lacerations Uterine rupture Invagination/retroflexion of uterine horn
‘Foal movement’ colics in mare - Signs? Diagnosis?
Mild-moderate medical colics
Common
Should respond to mild/moderate analgesia (buscopan or phenylbutazone)
Ischaemia/necrosis/rupture of caecum and colon colics in mare?
Syndrome of ischaemic necrosis of colon/caecum, potentially ending in rupture
Due to weight of foal applying pressure to viscera or stretching visceral blood vessels
Difficult to diagnose definitely - look for signs of peritonitis/endotoxaemia
Difficult to manage - lesions may be inaccessible at exploratory laparotomy
Uterine torsion colics in mares (pre-parturient): How common? When? Signs? Diagnosis? Treatment? Prognosis?
Rare Usually last third of pregnancy Usually low grade chronic or intermittent colic, but can be severe Diagnosis: - rectal palpation - one tight broad ligament - vaginal exam not helpful (twist cranial to cervix) Treatment: - surgery - standing flank laparotomy - GA and midline laparotomy - rolling under GA not recommended Prognosis after surgery: - 50% for live foal - 70% for live mare
Ventral oedema in pregnant mare?
Some mares develop large plaque of ventral oedema near term
May be due to compression of lymphatic drainage by foal
If mare well and oedema uniform and non painful then no treatment required - will resolve post foaling
Need to differentiate from other causes of abdominal enlargement
Pre-pubic tendon rupture in pregnant mares? Cause? Signs? Treatment?
Due to weight of foetus - more common in older mares
Large plaque of painful oedema, continuous with udder (‘dropped’ udder)
May be bloody discharge in milk
Often colic signs
Often spends more time recumbent
Treatment:
- analgesia (bute)
- will need assistance with foaling as cannot use abdominal pressure
- caesarean?
- will resolve if mare nursed through to foaling but often becomes more painful and results in euthanasia
- if survives do not breed from again
Hydrops amnion/hydrops allantois in pregnant mare? What is it? Signs? Diagnosis? Treatment?
Excessive fluid in allantoic/amniotic space
Up to 200L
May eventually cause colic, dyspnoea, recumbency, circulatory collapse
Foals usually deformed
Diagnosis: rectal exam (huge fluid filled uterus but foal out of reach)
Treatment:
- induce foaling or abortion
- dilate cervix, drain fluid off slowly
- manually remove foal
- IV fluids to maintain systemic BP
Placentitis in pregnant mares - Problems? Causes? Signs? Diagnosis? Treatment?
Eventually leads to abortion Ascending infection from cervix Strep, E.coli, Aspergillus Signs - premature udder development and lactation +/- vaginal discharge Diagnosis: - clinical signs - US demonstration of placental thickening - cervical swabs if discharging Treatment: - potentiated sulphonamides - bute
Varicose veins (varicosities) in mares - Problems? Treatment?
Most common cause of vaginal bleeding in mare - intermittent vulvar bleeding, blood pooling, worse at oestrus
More likely in pregnant or older mares
Usually no treatment required
Can do ligation/cautery/laser photocoagulation of vessels
Things needed for dystocia?
Sedation (and ketamine?) Clenbuterol or buscopan Local anaesthetic (epidural) Doxapram Foaling ropes Lubricant Hibiscrub Needles/syringes Waterproofs
Order of approach to dystocia?
Get things ready
Warn owner - guarded prognosis (may lose both)
Restrain mare (sedation? twitch? clenbuterol?)
Check mare not in shock/haemorrhaging
Clean perineum/arms
Vaginal exam - plenty of lube
Ascertain presentation/posture/position
Decide if vaginal delivery possible - if not refer for caesarean or euthanise
Check time if foaling possible and apply ropes/start traction
If no clear progress within 15 mins, re-assess, consider caesarean or controlled vaginal delivery under GA
Terminal caesarean = GA mare, cut foal out, euthanise mare
Embryotomy last resort - very damaging to mare unless operator very skilled
Uterine rupture/tear in pregnant mares - Problems? Diagnosis? Treatment?
Clinical signs evident 24-72h post foaling
If complete rupture, foal may fall into abdomen - no palpable in birth canal
Mare may fatally haemorrhage or will develop fulminating peritonitis and fatal endotoxaemia
Extract foal and consider euthanasia of mare
Smaller tears may only show as signs of peritonitis after foaling - better but still guarded prognosis
Diagnosis:
- clinical signs
- rectal/vaginal exam
- US
- peritoneal tap
Treatment:
- medical treat as for peritonitis
- exploratory laparotomy and repair for full thickness tears
Perineal lacerations during foaling - Significance/problems? Treatment?
Minor perineal lacerations are common during foaling
Many will heal without intervention
Lacerations which substantially disrupt perineal anatomy should be repaired, especially if natural healing will alter perineal conformation
This may be done immediately, or delayed for a few days if bruising is severe
Administer antibiotics/Nsaids/tetanus cover
Third degree perineal lacerations during foaling - How? Treatment?
Where foal’s foot has penetrated rectum and torn through anus
Rectum, vulva and vagina all communicate
Do not repair immediately - will break down
Administer antibiotics/Nsaids/tetanus cover
Repair required if mare to conceive again!
Delay surgery for 4-6 weeks until granulated in
Surgery difficult, several attempts often needed before complete repair occurs
Recto-vaginal fistulas – treat in same manner- delayed repair
Cervical lacerations in mare - Significance? Treatment?
May heal spontaneously or may need surgical repair
Repair probably best delayed until uterus involuted and inflammation subsided (one month post partum)
Therefore note and monitor – if cervical incompetence occurs mare will be sub -fertile
‘Uterine cramps’ causing post partum colic in mares - Signs? Treatment?
Many colics soon after foaling are put down to post-partum uterine contractions
Mild to moderate colics, no sign endotoxaemia
Should resolve with buscopan or phenylbutazone
What causes ischaemia/necrosis/rupture of caecum and colon causing postpartum colic of mares?
Expulsive forces of foaling
Inversion of uterine horn causing postpartum colic of mares - Cause? Signs? Diagnosis? Treatment?
After forceful foaling or too forceful removal of retained membranes
Colic which reoccurs despite analgesia
If mare continues to strain may proceed to uterine prolapse
Diagnosis by vaginal and rectal exam
Treat with analgesia, smooth muscle relaxants (buscopan/clenbuterol), manual replacement, uterine lavage
Colonic torsion causing post partum colic in mares? Cause? Treatment?
Post-partum mares prone to colonic torsion
Due to sudden increase of space in abdomen post foaling?
A surgical colic and rapidly fatal unless quickly corrected.
Rupture of uterine artery causing post partum colic in mares - What happens? Signs? Diagnosis? Treatment?
More common in older mares (atrophy of smooth muscle walls with fibrosis of arterial wall)
Haemorrhage may occur into broad ligament or into abdomen
Mild to moderate colic signs, which may progress to signs of haemorrhagic shock
May not respond well to Nsaids – painful?
May be contained within broad ligament, but if this ruptures or mare is haemorrhaging directly into abdomen then is likely to be rapidly fatal
Diagnosis:
- gentle palpation of broad ligament per rectum
- abdominal and rectal ultrasonography
Treatment:
- keep quiet – sedate?
- analgesia
- IV fluids – judiciously
- blood transfusions
- clotting agents – amino caprionic acid?, 10ml 10% formalin in 1 litre saline?
Uterine prolapse post partum in mares? Cause? Problems? Treatment?
Uncommon
After excessive traction on foal or RFM
After difficult foaling or if mare exhausted
May rupture uterine vessels and cause fatal internal haemorrhage
Even after replacement, death from metritis and endotoxaemia not uncommon
Treatment:
- clean uterus
- replace under epidural anaesthesia (standing sedation/GA)
- give oxytocin once replaced
- broad spectrum antibiotics and NSAIDs for anti-endotoxic effects
(rectal prolapses have similar aetiology and treatment – prognosis also poor as irreparable damage to blood supply of rectum usually has occurred)
Retained foetal membranes in mares - When normally passed? When to intervene? Problems if left?
2-10% of all foalings
Normal = within 2h post foaling
>4 hours is abnormal
When to intervene is controversial - most stud vets would advise treatment if still retained 4-6 hours post foaling
If left they decompose rapidly -> metritis -> endotoxaemia -> severe laminitis and death
Not all mares succumb to endotoxaemia - some tolerate RFM very well, others become very sick very quickly
Heavy horses traditionally considered very susceptible to effects of RFM
Each case must be taken seriously and treated promptly
Treatment for RFM in mares?
Oxytocin, antibiotics, flunixin (anti-endotoxic effects)
Check tetanus cover
Oxytocin alone may be enough to quickly stimulate passage
Poss manual removal (some think causes endometrial damage):
- gentle traction on allantois
- if doesn’t work, continued twisting of allantois is usually successful
- check placenta for retained fragments (tip of non pregnant horn most likely)
- if looks complete, 3-5d antibiotics and NSAIDs, rectal exam only if necessary
- if retained fragment cannot be located and removed, uterus lavaged until fluid is running fairly clear
- administer more oxytocin after lavage and turn out to exercise (aids involution)
- re-exam for further lavage in 12-24h
- maintain on antibiotics/NSAIDs
- keep lavaging until uterus involuting and little uterine fluid being generated
Metritis post partum in mares - Causes? Problem? Treatment?
May be due to unnoticed partial retention of placenta or due to contamination of uterus during foaling
May cause fatal endotoxaemia +/- laminitis if untreated
Treatment: antibiotics, NSAIDs, oxytocin and lavage (same as for RFM)
Signs of peri-parturient hypocalcaemia in mares?
Uncommon Muscle fasciculations recumbency Tetany Diaphragmatic flutter 'thumps'
Ideal external genitalia conformation of mares?
Labia vertically orientated
2/3 vulvar opening below floor of pelvis
Upwards orientation of vestibular opening - contamination if horizontal
What conformation problems can mares have which contribute to reproductive performance? How can they be helped surgically?
Pneumovagina - Caslicks, perineal reconstructions (Gadds)
Urovagina - urethral extension
Cervical incompetency - cervical repair
Delayed uterine clearance - uterine suspension
Oviduct blockage - oviduct lavage, prostaglandin
When is the Caslick’s procedure done? Method?
To improved vulvar competence - pneumovagina
Stocks/against doorway
Tail bandaged and held out of way
Wash perineum
Local anaesthesia
Excise thin band of mucosa from each side (3-4mm) from dorsal commissure
Do not oversuture in older mares - urovagina
Suture with non-absorbable material
Remove sutures 10-14 days later
Must open up close to foaling or will tear
When is the Gadds procedure performed?
= perineal reconstruction
Older mares - loss of perineal body, straight vestibule
Second degree perineal lacerations
When is urovagina seen in mares? Diagnosis? Surgical management?
Usually old, pleuriparous mares Often with pneumovagina Confirm diagnosis by cytology Rule out ectopic ureter in young fillies Improve BCS if thin Surgical management: - caudal relocation of transverse fold - urethral extension - urethral suspension?
What cervical injuries can mares get during parturition? When to treat?
Lacerations - surgery during diestrus >3 weeks post partum, stay sutures for traction, 3 layer closure
Adhesions
Incompetence
What surgery can help post mating persistent endometritis?
Uterine suspension:
- Restoration of normal horizontal orientation of uterine horns
- Improves uterine clearance
- Improves perineal conformation
- May reduce urine pooling
When do perineal lacerations usually occur in mares? Degrees? Treatment?
Usually during unassisted foaling of primiparous mares
First degree lacerations = mucosal damage - Caslick or no surgery required
Second degree lacerations = mucosa, submucosa and perineal muscles - Caslick and reconstruction of perineal body
Third degree lacerations = complete disruption of rectovestibular shelf, perineal body and anus - requires surgical repair, delay repair for 4-6 weeks
What causes a rectovestibular fistula during foaling?
Penetration of foal’s foot into rectum without progression to 3rd degree perineal laceration
Grnaulosa Cell Tumours (GCT) - Characterstics? Clinical signs? Diagnosis? Treatment?
Most common neoplastic disorder of mares' ovaries Unilateral Rarely metastasise Good prognosis Behavioural signs: - an oestrus/continuous oestrus - stallion like behaviour/aggression Diagnosis: - rectal exam: enlarged ovary - US: distinct honeycomb like appearance - endocrinology: increased testosterone in 50%, increased inhibit in 85%, increased Anti-Mullerian Hormone in 98% Treatment: - ovariectomy by laparoscopy (standing or under GA) or laparotomy under GA
What does it mean if an owner rings and says mare has ‘red bag delivery’?
Placenta has prematurely detached from uterus
= dystocia - emergency
Provide advice over phone
Options for dystocia?
Assisted vaginal delivery - conscious, use traction +/- ropes, sedation and epidural if mare straining excessively
Controlled vaginal delivery - mare anaesthetised +/- hindlimb elevated, delivered per vaginum
Caesarian section
Embryotomy
What is the gubernaculum?
Cranial - proper ligament of the testis
Middle - ligament of the tail of the epididymis
Caudal - scrotal ligament
