2.7 Equine repro abnormalities and disease

Indications for Caslick’s vulvoplasty (5)

• Poor perineal conformation and subfertility

• Pneumovagina (incompetent vestubular fold → air sucking)

• Cervicitis and endometritis (possibly from faecal contamination)

  • Endometritis is main reason

• Perineal tears

• Repetitive foaling

When does a Caslick’s vulvoplasty need to be removed?

Before foaling → foal needs to come out

• Path of least resistance - if Caslick’s then could force itself out elsewhere with fatal damage

Steps of Caslick’s vulvoplasty (3)

• Anaesthetise and restrain the horse

• Remove 0.5-1cm of mucosa close to the internal margin of the vulva

• Appose and suture the vulva lips

  • leave space for peeing at bottom of vulva

What impact on the cervix does ageing have and how does this lead to inflammation? (3)

• Cervical fibrosis

• Cervix cannot fully relax after oestrus

• Semen debris builds up → inflammation

Most common uterine neoplasia

Leiomyoma (smooth muscle)

• but rare

How do foreign bodies in the uterus affect the horse?

Mimic pregnancy → pauses cycle, mare cannot come into oestrus

• marbles can be used for same effect

What causes CEM and where is it carried asymptomatically?

• Taylorella equigenitalis → notifiable

  • Pseudomonas and Klebsiella can cause similar disease

• Clitoral fossa and sinus

3 clinical signs of CEM

• Acute metritis

• Copious creamy vulval discharge

• Early return to oestrus (occurs with basically any infection)

Metritis V endometritis

Endometritis is more superficial tissue → less severe

2 main pathogens responsible for endometritis (if infectious)

Ascending urogenital or GIT pathogens

• E. coli

• beta haemolytic Strep

Cutoff point for inflammation indicating endometritis after breeding

If inflammatory response persists 12+ hours (free fluid in lumen of uterus) → endometritis

3 conformational abnormalities potentially responsible for endometritis

• Sloped perineum

• Pendulous uterus

• Urine pooling

3 clinical signs for endometritis

• Excessive intraluminal fluid

• Prolonged, early return or erratic oestrus (without ovulation)

• Failure to conceive or early embryonic death

3 methods to extract a pathogen for culture in endometritis

• Endometrial swab

• Low volume lavage

• Endometrial biopsy

2 treatments to remove the fluid in utero for endometritis

• Oxytocin (ecbolic agent)

• Uterine lavage with saline or Hartmans (clean but not sterile)

3 methods to treat endometritis infection

• Intrauterine antibiotics

• Antibiofilm agents (H2O2, EDTA)

• Lavage

2 indications for uterine lavage

• Prevention of endometritis (lavage with penicillin during oestrus)

• Used for culture and cytology

Endometrial V lymphatic cysts

• Endometrial cysts <10mm

• Lymphatic cysts >10mm

What is this in the ovary and what is it caused by? (2)

• AHF (anovulatory haemorrhagic follicle)

  • Anechoic, irregular wall, ‘snowball’ fibrin speck effect

• Idiopathic lack of LH surge → failure to progress ovulation

• (some suggest PGF2a treatment but most eventually regress with time to return to normal cycling)

What does the contralateral ovary look like in AHF and granulosa theca cell tumour?

• AHF → contralateral ovary normal

• Tumour → produces hormones → -ve feedback → contralateral ovary smaller

4 signs of granulosa theca cell tumour

Hormone producing benign tumour:

• Locally enlarged - discomfort

• Inferfility

• Extreme aggression

• Nymphomania

Most sensitive assay for granulosa theca cell tumour

Elevated AMH

2 most common causes of foetal loss after 6+ month gestation

• Excessive twisting of umbilical cord (long in horse)

  • does not predispose subsequent pregnancies

• Placentitis 

3 signs of chronic placentitis during pregnancy

(acute - mare aborts with no signs)

Chronic

• vulval discharge

• premature lactation (running milk)

• Preliminary foaling signs (e.g. softening of pelvic ligaments

What is CTUP and how thick should it be? What does increased and reduced CTUP mean?

• CTUP = combined thickness of uterus + placenta

• 1+ gestational age in months (e.g. 7 month gestation = 8mm)

• Increased = placentitis

• Reduced = placental insufficiency

2 types of antibiotic treatment for placentitis

Need to cross placenta:

• Penicillin + gentamicin

• Sulfonamides + trimethoprim

First pathogen assumed when abortion is seen

Equine herpesvirus

3 pathological signs of EHV

(only definitive diagnosis is PCR)

• Jaundiced mucous membranes

• Increased peritoneal and pleural fluid

• White or yellow pinpoint liver lesions

What do red, yellow and green groups mean in terms of EHV?

• Red = affected

• Yellow = in contact

• Green = safe geographical distance away (since EHV is respiratory and spread via aerosols)

When should EHV vaccinations be given to in-foal mares?

5, 7, 9 months of gestation

Why do equine cryptorchidism cases always need to be castrated?

Behaviour and neoplasia risk

What does a horse being cut proud mean?

Incomplete castration (often juvie or undeveloped testicle when castrated) → make testosterone

3 causes of paraphimosis + priapism

Paraphimosis → inability to retract penis into prepuce

• Secondary to trauma and oedema

• Pudendal nerve damage

• Acepromazine

3 signs of paraphimosis + priapism

• Oedema + increased weight → fatigued retractor muscle

• Swelling → venous and lymphatic drainage impaired

• Exposure of penis → tauma, infection, cellulitis → fibrosis and loss of erectile function

3 treatments for paraphimosis and priapism

• Reduce oedema

• Replace penis (if possible) - pursestring suture on sheath

• Long term → retractor muscle too fatigued to keep it in: amputation, salvage procedure, perineal urethrostomy