Reproductive Surgery, Mare + Foal Flashcards
Describe the normal placenta of a horse.
Chorioallantoic, diffuse placenta
Should weigh 11% of foals BW
Describe the normal gestational length and length of each stage of parturition in a mare.
Gestation = 341 days
Stage 1 = can be days to weeks
Stage 2 = 10-20mins, anything over 20 mins is abnormal
Stage 3 = within 3 hours of stage 2
Name the signs that would indicate a mare is going to foal soon, and when do they appear?
Bagging up - 2-6 weeks
Waxing up - a few days
Slackening of sacroiliac ligaments and vulva - a few days to the day of
Dripping milk - 24-48 hours, but they might not get to this stage if they foal early
Nesting behaviours - may or may not happen, a few days
Foaling alarms can be used to help - if they are the halter alarms then they go off when mares lay down so it depends on how much the mare likes to lay down and sleep (can be days before they foal or it could be that night - the point is you need to be checking them everytime it goes off), otherwise the vulva ones only go off when there is stretching and dilation of the vulva so at the start of stage 2
Changes in milk electrolytes (strip testing) - within 24 hours
Explain what happens in a normal stage 1,2, 3 of parturition.
Stage 1 - colic-like, pacing, pawing at the ground, rolling, laying down and getting up frequently, sighing, flank watching, can be days or longer, often longer in maidens
Stage 2 - rupture of membranes, see a white bag and often feet coming out of the vulva, mare may or may not initially lie down (they usually lie down but some mares are dumb), mean time of 11 mins, should be able to feel 2 front feet slightly offset and a nose, then the foal will come out (yay)
Stage 3 - passing of the placenta, should be within 3 hours of stage 2, check the placenta for colour, texture, weight, if its all there (super important)
What are some differentials for GI or colic like signs seen in mares immediately post-foaling? (hint: there are 9)
GI: impaction/obstipation (pain), large colon volvulus, small colon ischaemic necrosis, caecal impaction
Urogenital: RFM, uterine haemorrhage, uterine tear, bladder injury/prolapse, vaginovulval bruising
What’s the 1,2,3 rule?
Foal should be standing in 1 hour
Nursing in 2 hours
Placenta passed in 3 hours
How do we know if there are retained foetal membranes and how do we treat them?
If the placenta is still hanging out of the vulva after 3 hours, if the placenta came out but there’s a bit missing
Treatment - removal using gentle traction, oxytocin 1-2ml IM/IV q2-4h (alternate the routes), or CRI 1 IU/min, uterine lavage (Burn’s or Dutch technique)
Analgesia, anti-inflammatories +/- antibiotics if they aren’t clinically well, if just local infection then put the AB in flush bag and put it straight into the uterus (large volume flush for dystocia cases, small volume flush for normal parturitions)
Name the clinical signs of periparturient haemorrhage and how do we diagnose it?
Painful, tachycardia, pale MM, colicky, tachypnoeic
Diagnosis - abdominal US, per rectum US if contained in broad lig., +/- abdominocentesis (often not needed)
How do we treat periparturient haemorrhage?
Close monitoring
Antifibrinolytics - tranexamic acid 5-10mg/kg
Sedate the mare
If giving oxygen is going to stress the mare out then don’t do it - it doesn’t help that much anyway
If you are going to give fluids just make sure its not Hartmans
How do we treat uterine tears?
Antibiotics, anti-inflammatories - TS and bute/flunixin probs
If its a small tear and there is localised peritonitis then medical treatment as above +/- a drain
If its a large tear with generalised peritonitis you need to drain and surgically explore as well as AB + AI
What is the maintenance fluid requirement of a foal? What is it for an adult horse?
Foal - 100ml/kg/day
Adult - 60ml/kg/day
What is the most common congenital cardiac defect in horses?
Ventricular septal defect (VSD)
What are the normal vital parameters in a foal?
HR - 60-80bpm after birth; 120-150bpm for the first few hours then evens out to 80-100bpm
RR - 60-80/min after birth; then equilibrates to 20-40/min after a few hours
Cardiovascular - arrhythmias common in the first 15 mins and murmurs in the first few days (PDA should close within 7 days), digital pulses and warm extremities
Respiratory - crackles are common and can be normal
Umbilicus - should be dry within 24 hours
What do you need to include in a neonatal physical exam? What conditions might you find?
Cardiovascular - auscultation, arrhythmias common in first 15 mins, murmurs common for the first few days, presence of digital pulses + warm extremities; looking for VSD, other congenital conditions, poor perfusion, MM colour and hydration
Respiratory - auscultation is insensitive for pneumonia + infection, crackles can occur commonly due to compliant chest walls, dependency atelectasis, poor surfactant immaturity
Joints - any swelling, can be septic arthritis
Umbilicus - enlarged or painful, patent urachus (dripping urine)
Eyes - ulcers, entropion, scleral haemorrhage from dystocia/sepsis
Hard palate - congenital abnormalities, nasogastric regurgitation is common especially in weak foals
Limbs - looking for angular or flexural limb deformities
Meconium staining - from foetal distress
Maturity - domed head, silk coat, lax tendons, no ear cartilage
Coprophagy - foal heat
What is the most appropriate way to restrain a foal for physical exam?
Hold them by the chest and hamstrings
Can grab the tail or an ear if necessary
Describe the normals of foal behaviour.
Sleeping 1/3 of the time, during play time the foal should stay quite close to the mare and the mare will be watching closely
Nursing 7x per hour in the first week, 3x per hour at 4 weeks
Urinating within the first 6 hours for colts, first 11 hours for fillies; they should produce 6-7ml/kg/hour (7-8L urine/day)
Defeacation meconium within the first 3-6 hours
What are the 3 most important checks in newborns?
IgG - marker of passive transfer
USG - best marker of dehydration/whether or not the foal is nursing
Umbilicus - make sure you dip is judiciously with dilure disinfectants
What value is considered a PASS in terms of adequate protection in an IgG test?
> 8g/L
At what time should we check IgG in newborn foals and why? How does our management of failure of passive transfer change after the foal is 1 day old?
Around 12 hours is good as we have past the maximum absorption time (<6 hours) but we still have enough time to supplement enteral colostrum if they aren’t adequately protected before the channels close at 24 hours old. After that we would have to use IV plasma
What USG indicates dehydration in foals?
USG >1.014
Explain normal foal clinicopathology.
Relatively low PCV and TS (TS>60g/L can be used as a surrogate for an IgG test)
Neutrophil:Lymphocyte >1:1
High ALKP
High creatinine in the first 36 hours due to placenta - if it persists longer than 36 hours then the foal might have renal dx or the placenta was not working as it should
Explain the difference between open and closed castration.
In an open castration the tunica vaginalis is opened and retained.
In a closed castration the tunica vaginalis is not opened and is resected along with the testis.
Name the complications of castration. Which 3 are the most common?
Most Common:
Haemorrhage
Swelling/oedema
Infection
Others - hydrocele, evisceration/herniation, penile complications (priaprism, paraphysmosis, iatrogenic trauma), persistent masculine behaviour
How do we manage haemorrhage as a complication from castration?
Locate + clamp/ligate the bleeding stump - can do standing most of the time
Re-emasculate the stump
Pack with gauze sponges (laparotomy sponges or sterile bandages), + close scrotum
GA –> haemostasis
How do we manage swelling/oedema as a complication of castration?
Establish drainage by enlarging the incision - can do standing under sedation
AIs +/- ABs (TS or pen)
Aggressive cold hosing x2/day
Exercise - stick them on the walker for 15 mins/day
How do we manage infection as a complication of castration?
If localised - drainage, take a swab for culture, and give BSABs and AI in the mean time (usually a 7d course of peniillin or TS and some bute)
If secondary peritonitis - treat as peritonitis
If scirrhous cord - surgery
How do we diagnose cryptorchadism?
Clinical signs
Clinical exam + rectal exam +/-US
Hormonal assays - testosterone, hCG stmulation in horses older than 2 and donkeys, serum oestrone sulphate in horses older than 3
Name the most common penile tumour and how it is treated.
SCC
Treatment Options: combination scalpel + cryotherapy or cryotherapy + topical chemo
Scalpel (or laser) excision
Cryotherapy
Posthioplasty (reefing) - if there are multiple sites then remove affected tissue and re-anastomose
Amputation - if its invaded into the tunica albuginea
En bloc resection - pelvic urethrotomy for advanced disease
Chemotherapy - topical 5-fluorouracil, generally takes about 3 treatments
What is the difference between priaprism and paraphimosis?
Priaprism is persistent erection due to vascular engorgement of the corpus cavernosum penis.
Paraphimosis is an inability to retract the penis, often secondary to trauma, ACP use or cachexia.
How do we treat paraphimosis?
Aggressive topical + systemic AI therapy - NSAIDs, corticosteroids, DMSO
Manual massage, emollient application, cold therapy
Reduce and maintain in prepuce
Elastic bandage + sling
Surgery as last result - irrigation of CCP, create a shunt between the cavernosum and spongiosum, or can phallopexy or phallectomy
Describe the importance of passive transfer of immunity.
Due to epitheliochoral placenta foals are born immunocompetent and immunonaive and rely on colostrum for transfer of maternal antibodies.
51% of passive transfer occurs at less than 12 hours of age so it is important that colostrum is ingested from the first nursing.
How does colostrum differ in composition from milk? What 3 immunoglobulins make up the majority population in colostrum?
Colostrum has higher protein + fat and lower lactose than milk
Immunoglobulins - IgGa, IgGb, IgG(T) > IgM, IgA, IgE
What factors decrease colostral quality?
Age of the mare >15 yo
Breed - Arab, TB > STB
Stressed or ill mare
PPID
Amount of time post-partum
What is the ideal intake of colostrum?
60-90g of IgG in the first 6 hours after birth, approx. 1-1.5L of good quality colostrum (>60g/L) should result in a PASS on IgG testing
What is the easy, in field way to test colostrum quality?
Brix refractometer - anything above 30% is brilliant and should correlate to an IgG >8g/L, but anything above 15% is of fair quality still.
What is sepsis?
Infection + systemic inflammatory response syndrome (inflammatory dysregulation)
What 4 routes of infection lead to neonatal sepsis? Which is the most common?
- Oral - most common
- Umbilicus
- Respiratory
- Pre-partum/in utero infection
List the most common organisms causing neonatal sepsis?
E. coli!!!!!
Klebsiella, enterococcus, salmonella, streptococcus, staphylococcus, actinobacillus, pasteurella, clostridium, bacteroides
What are the predisposing factors for neonatal sepsis?
Maternal illness
Failure of passive transfer
Placental infection or insufficiency - placentitis
Short or long gestational periods - premature or post-mature
Inadequate attention to umbilical stump
Poor hygiene - preparation of mare pre-foaling (clean her up, bandage her tail, clean foaling box), foal examination (no gloves), keep the mare in the foaling environment for 1 month prior so they produce antibodies to the relevant bugs
What are the clinical signs of neonatal sepsis?
QAR/obtunded/stuperous/comatose
Reduced appetite
Inc. HR
RR increased but can be dec. if particularly sick
Hypothermia - due to poor peripheral perfusion (shock)
Initially bright red MM with rapid CRT but eventually MM become dark with prolonged CRT
Haemorrhage of MM including episcleral in advanced sepsis, make sure you check the inner pinnae, can advance to DIC
Reduced jugular fill
Weak peripheral pulses + cool extremities
Reduced urine output
Other signs of dehydration - sunken in eyes, inc. USG
Diarrhoea
+/- joint effusion if synovial
Wet and soft umbilicus
Uveitis
Distal limb necrosis - if there are septic thrombi
Neurological signs - if meningitis component
Dermatitis, skin sloughing
Do you need a bacterial culture to confirm a diagnosis of neonatal sepsis?
No
What clinicopathological changes are associated with neonatal sepsis?
Usually an inadequate IgG
Neutropaenia with bands and toxic changes
Hypoglycaemia
Hyperlactataemia
Metabolic acidosis
Discuss the resuscitative care for a foal with neonatal sepsis.
Early antimicrobials - no enterals (reduced gut perfusion due to shock), pen-gent is a good firstline, can use ceftiofur 5-10mg/kg IV/IM q6-12h, gentamicin 12mg/kg q36h, penicillin (w/out procaine) 22,000-50,000IU/kg QID IV
Can do cephalosporins and penicillin as CRIs
ANYTHING GIVEN INTRAMUSCULARLY SHOULD BE IN THE BUTT NOT IN THE NECK
Put the antibiotics in the fluid bag.
Early fluid therapy - 1L at a time, heat it up for 1 minute in a 1000W microwave and give it a good shake so there’s no hot spots (don’t want venous necrosis), can use anything just not hypertonic saline.
Give the first 20ml/kg (about 1L in a 50kg foal) and then assess perfusion, CRT, digital pulses, MM colour, extremity temperature, jugular fill, mentation, urination volume, USG.
If there is an insufficient response give another 20ml/kg, can give up to 3 boluses of 20ml/kg (about 3L of fluid).
If they are still hypovolaemic/hypotensive after 3L of fluid then give them pressors/inotropes or some other drug and send them to a referral institution
Supportive care - glucose (20mL 50% per 1L), parenteral nutrition, don’t bother with oxygen if they are getting more stressed and hyperventilating, no active warming, take care of any wounds, take samples!!
If you can’t easily take samples then give them the ABs and send them anyway, it will reduce sensitivity but it could save their life.
REFER THEM EARLY ON FOR THE BEST PROGNOSIS
You’ve provided resuscitative care for a foal with neonatal sepsis and its stabilised. Well done! Describe the ongoing care for that foal.
Antibiotics and fluid therapy - 100ml/kg/day
Flunixin - 1.5mg/kg q24h
Plasma if their IgG is inadequate
Nutrition - 4-8mg/kg/minute glucose parenteral vs enteral, 50ml milk q2h for trophic feeding
Monitor ins and outs - urine production
Respiratory/ventilation support if they lose drive and become weak
Regular turning, standing, moving, nursing
Eye care
Instrument care - change lines frequently and catheters, bungs, extensions
What is the survival rate for neonatal sepsis?
50-70%
What is a caslick procedure?
A procedure where the cranial 2/3 of the vulva are sutured together to prevent faecal contamination of the vagina which can lead to ascending endometritis and pyometra, affecting the mares ability to maintain a pregnancy.
It’s done by doing an epidural and/or line blocking the margins of the vulva and then incising along the mucocutaneous junction, then suturing the fresh edges together, leave the sutures in for 10d and then remove.
What are the indications for doing a caslick procedure in a broodmare?
Poor vulval conformation - poor vulval apposition, more than 1/3 above the pelvic brim, more than 10 degree cranial tilt.
Pneumovagina
Splachnoptosis = cranial prolapse or forward retraction of the viscera creating a shelf-like appearance of the cranial vulva.
Describe the 3 grades of perineal lacerations and how to manage them.
First degree - superficial mucosa and muscles of the labia and vestibule are torn or damaged; manage with local wound care, daily cleansing with saline, antibiotics, and AIs
Second degree - tearing + disruption of the constrictor vulvae muscle and perineal body only; debride and suture superficially, can Caslick them, give tetanus prophy if they didn’t get it before foaling, antibiotics + AIs
Third degree - damage + disruption of perineal body, anal sphincter + rectum; manual daily evacuation of the vagina until the mucosa heals, delay corrective surgery for 6 weeks, ensure soft faeces pre-op by giving a soft laxative diet, mineral oil + Epsom salt drenches, then recreate the shelf between rectum and vagina + restore the perineal body
Discuss the 4 different ways of diagnosing an ovarian tumour and the recommended treatment.
- History and clinical signs - behavioural abnormalities if GCT
- Rectal palpation
- Rectal US
- Serum hormonal assays - AMH, but can also do testosterone, inhibin
