Equine Reproduction Flashcards Preview

Year 4 > Equine Reproduction > Flashcards

Flashcards in Equine Reproduction Deck (134)
1

By when are testes adult size?

5 months

2

When does the Gubernaculum shorten and the testes regress in size?

8.5 months

3

What do the cranial, middle and caudal Gubernaculum become?

Cranial: proper ligament of testes
Middle: ligament of tail of epididymis
Caudal: scrotal ligament

4

Why might you castrate a horse?

Prevent breeding
Modify behaviour
Neoplasia/ inguinal hernia

5

Why should you palpate the testes before castration?

Check both testes are palpable
Check for hernias

6

What are the 2 anaesthesia options for castration?

Standing sedation
GA
Field anaesthesia vs GA under theatre conditions (field is safer for horse)

7

How would you sedate a horse for a castration?

Alpha-2 agonist (eg detomidine) plus an opiate (eg butorphanol)

8

Describe a standing castration

Sedation (alpha 2 agonist plus opiate)
Bandage the tail
NSAIDs and antibiotics
Aseptic preparation of scrotum (Chlorhexidine)
LA (10-15ml)
Repeat scrub of scrotum
Incise close to median raphe (most dependent site)
Bold incision away from you
Ensure good drainage

9

How should a horse be positioned for a field castration?

Lateral recumbency
Elevate upper HL/pull forwards out of the way
Castrate lower testicle first

10

What induction agent would you use for a horse castration?

Ketamine

11

Are open or closed castrations generally performed on horses?

Open

12

What might make you decide to do a closed castration instead of open?

Older horse
History of herniation/swelling

13

Where should you tie a suture when castrating a horse with a history of scrotal/inguinal hernia?

Around vaginal tunic +/- suture superficial inguinal ring

14

What aftercare should you do after castration?

Check tetanus status
Antibiotics
NSAIDS
Box rest for 24 hours followed by controlled exercise
Keep away from mares

15

When should you advise an owner to contact the practice after castration?

Blood dripping from incision persisting >4 hours, or steady stream of haemorrhage
Evidence of tissue hanging from incision
Marked swelling of scrotum/stiffness that persists >3 days
Depression/inappetence/colic

16

Give some complications following castration

Swelling
Haemorrhage
Omental prolapse
Evisceration
Septic funiculitis
Clostridial infection
Septic peritonitis
Penile damage
Hydrocele (fluid accumulation around testis)
Continued masculine behaviour (learned behaviour or incomplete castration)
Incomplete cryptorchid castration

17

What is cryptorchidism?

Retention of one or both testes along normal path of descent

18

How do you diagnose cryptorchidism?

History (behaviour, previous surgery)
Thorough external palpation (sedate, castration scars? Palpable testicular structures?)
Hormone analysis (donkeys and horses <2 yo: hCG stimulation test) (horses >3 yo: oestrone sulphate assay) (anti-Mullerian hormone test)
Ultrasound
Rectal exam

19

Give some miscellaneous diseases of the testes

Anorchidism
Torsion of spermatic cord
Testicular neoplasia

20

What are the 2 types of inguinal herniation?

Direct and indirect
Direct occurs through a tear in the body wall (lies outside the vaginal tunic)
Indirect occurs via vaginal ring (lies inside the vaginal tunic)

21

How do you diagnose inguinal herniation?

Palpation
Ultrasound

22

What is the most common neoplasia of the penis?

Squamous cell carcinoma
Affects glans of penis
Squamous papillomas are pre-neoplastic

23

What other neoplasias can occur on the penis sheath?

Melanomas and Sarcoids

24

How do you treat penile squamous cell carcinoma?

Local excision/ cryotherapy/ topical chemotherapeutic agents
Surgery (distal phallectomy/remove glans/ segmental posthetomy/en bloc resection-resection of as much penis as possible plus lymph nodes, create a new urethral orifice)

25

What is the prognosis like for penis surgery in response to squamous cell carcinoma?

Good if treated early and appropriately

26

How can you prevent penile disease?

Clean sheath regularly (owner education)
Examine penis as part of yearly routine check up in older patients

27

How would you treat a case of penile trauma?

Ice packs/ cold hosing
NSAIDs and antibiotics
+/- referral
Penile support to reduce oedema (penile sling)

28

What might you see in a horse with penile trauma?

Severe swelling
Haematoma/ haemorrhage

29

What is priapism?

Persistent erection without sexual excitement

30

Why should you not give ACP to a breeding stallion?

Can cause priapism (persistent erection)

31

How do you treat priapism (persistent erection)?

B2 agonist
Lavage corpus cavernosum with heparin under GA (and remove blood)

32

What is paraphimosis?

Inability to retract penis into prepuce
Prolonged -> permanent
Pudendal nerve injury
Give GA, roll on back, gently put penis in sheath, purse-string suture across preputial orifice

33

What is phimosis?

Inability to protrude the penis

34

What is pyospermia?
What may cause it?

High no of WBCs in sperm
External infection
Cystitis, epididymitis, seminal vesiculitis

35

What is haemospermia?

Blood in ejaculate caused by high pressure in corpus spongiosum caused by external infection/ external injury/ urethral injury

36

What is urospermia?

Urine in ejaculate caused by external infection/ neurological dysfunction/ external injury/ urethral injury

37

When do the testes pass into the inguinal canal?

270-300 days

38

Give some complications following dystocia/parturition

Uterine prolapse
Uterine rupture
Uterine haemorrhage
Invagination/ retroflexion of the uterine horn
Retained foetal membranes
Cervical tears
Perineal lacerations/ recto-vaginal tears
Intestinal complications

39

What orientation should the vestibular opening of the mare be?

Vertical
Horizontal -> contamination

40

What are the anatomical barriers of the mare repro tract?

Vulva, vestibule/vestibulo-vaginal fold, cervix

41

What happens if the anatomical barriers of the mare repro tract are compromised?

Contamination, reduced fertility

42

Why may a mare have poor confirmation of the vestibular opening?

Injury, age, parity, body condition

43

Give some conformation problems in the mare and how you'd correct them

Pneumovagina (Caslick's, perineal reconstruction)
Urovagina (urethral extension)
Cervical incompetency (cervical repair)
Delayed uterine clearance (uterine suspension)
Oviduct blockage (oviduct lavage, prostagladin)

44

Give some advantages of AI

Semen can be transported- spreading genetic material
Semen can be stored– even after a stallions death
Ejaculates can be divided into smaller doses– more matings
Reduces risk of venereal disease
Reduces post mating endometritis
Semen can be examined readily

45

Give some 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 (must be natural matings)

46

Why may some over-large mares develop ventral oedema during pregnancy?
Is treatment required?

Compression of lymphatic drainage by foal
If mare is well and oedema is uniform and non-painful, no treatment is required (will resolve post-foaling)

47

Why does pre-pubic tendon rupture occur in some mares?

Due to weight of foetus (more common in older mares)

48

What clinical signs may you see in a pregnant mare with pre-pubic tendon rupture?

Large plaque of painful oedema, continuous with udder
May be bloody discharge in milk (rupture of blood supply to the mammary gland)
Often colic signs
Mare often spends more time recumbent

49

How do you treat pre-pubic tendon rupture in a pregnant mare?

Bute analgesia
Will need assistance with foaling, maybe C-section
Will resolve if mare nursed through to foaling, however often progressively becomes more painful- euthanasia
Don't breed from mare again

50

What is hyrops amnion/hydrops allantois?
What are the clinical signs?

Pregnant mare with excessive fluid in allantoic/amniotic space
Colic, dyspnoea, recumbency, circulatory collapse
Foals usually deformed
Heritable?

51

How do you diagnose hydrops amnion/allantois?

Rectal exam-huge fluid-filled uterus but foal out of reach

52

How do you treat hydrops amnion/ allantois?

Induce foaling or abortion
Dilate cervix, drain fluid off slowly
Manually remove foal
IV fluids to maintain systemic blood pressure?

53

What may cause placentitis in the pregnant mare?

Strep spp, E.coli, Aspergillus,
Ascending infection from cervix -> abortion

54

Give some clinical signs of placentitis in the pregnant mare

Premature udder development and lactation +/- vaginal discharge

55

How do you diagnose placentitis?

Clinical signs
Ultrasound (placental thickening)
Cervical swab if discharging

56

What is a stallion?

Entire male horse >4 years old
<4yrs old = colt

57

When does puberty occur in male horses?

12-24 months

58

When does the decent of the testes occur?

Normally descended into scrotum at/shortly after birth, but may occur up to 24 months old

59

When is maximum sexual maturity reached in stallions?

4-5 years, retained until about 20 years

60

How long does spermatogenesis take in the male horse?

60 days

61

What factors affect semen quality?

Testicular size (bigger = more semen)
Testicular efficiency (% of testicle that is producing sperm)
Age (younger = less sperm)
Frequency of ejaculations (no of sperm halves after each ejaculation)
General health/injury

62

What number of motile sperm is a suitable dose for natural service?
What about AI?

Natural: 500 million
AI: 150-500 million

63

What are the suggested rates for matings per week?

15 (variable)

64

How should you examine a stallion for breeding soundness?

Physical exam of external genitalia
Exam of internal genitalia
Observation of libido and mating ability (any ortho problems that would stop him mounting?)
Semen evaluation
Testicular biopsy (tru cut)

65

Where would you swab a stallion for CEM?

Urethra, urethral fossa, penile sheath, pre-ejaculatory fluid if available

66

What is CEM?

Contagious equine metritis (can be transmitted by stallion)
Notifiable

67

What do you vaccinate a stallion against?

Equine viral arteritis (abortion)
Stallions become carriers
Notifiable in stallions
Blood test first to prove seronegative

68

Why should you take serious action if a stallion has systemic illness?

Pyrexia affects sperm production

69

How should you treat penile/scrotal injury?

Anti-inflammatories (NSAIDs, maybe corticosteroids)
Cold therapy
Massage
Support
Diuretics?
Topical treatments

70

Why should you take extra care when rectalling stallions?

More excitable, more likely to struggle -> higher risk of rectal tears (also, narrower pelvis)

71

What should you check for when investigating colic in stallions?

Inguinal hernias, scrotal hernias, testicular torsions

72

Which neoplasias may stallions get on their penis?

Sarcoids, squamous cell carcinoma, melanoma, seminoma, other testicular tumours, papillomas

73

What is hydrocele?

Fluid around testicle from lymphatic drainage plexus

74

Give some other diseases of stallions

Haemospermia
Urospermia
Testicular degeneration
Hydrocele/varicocele (veins become enlarged inside scrotum)
Orthopaedic disease
Psychological dysfunction (eg frustration if not allowed out with other horses)
Cushings

75

By when should fresh semen be used?

Few hours

76

What are semen 'extenders'?

Increase lifespan of sperm, may contain antibiotics
Often milk/egg-based products

77

How long can chilled semen last?

Up to 48 hours
Mixed with extenders then slowly cooled to 5 degrees

78

Frozen semen is separated into doses of what size?

0.25 - 5ml
Multiple straws used per mare

79

What is frozen semen treated with?

Extenders and cryoprotectants

80

How is frozen semen stored?

In liquid nitrogen flasks

81

How long does frozen semen last?

Forever (provided liquid nitrogen is topped up)

82

How are fresh and chilled semen inseminated into mare?

Through cervix, from a loaded syringe, via an insemination catheter

83

How is frozen semen inseminated into mare?

Straws warmed to 37oC in water bath, dried, unsealed and inseminated via insemination 'gun' either just through cervix or into uterine horn on side of ovulation (deep uterine insemination)

84

When in the mare's oestrus cycle should you inseminate with fresh and chilled semen?

Same for natural service: up to 48 hours before ovulation

85

When in the mare's oestrus cycle should you inseminate with frozen sperm?

Best done as close to ovulation as possible as survival time of sperm is not as long (up to 12 hours before or 6 hours after ovulation)

86

Give some pre-parturient colics in pregnant mares

'Foal movement' (mild-moderate, common, should respond with mild/moderate analgesia eg buscopan or phenylbutazone)
GI colic
Actually foaling or aborting (do vaginal exam)
Uterine torsion
Ischaemia/necrosis/rupture of caecum or colon (may result in endotoxaemic shock; due to weight of foal applying pressure to viscera/stretching visceral blood vessels)

87

How do you treat placentitis in the pregnant mare?

Bute
Potentiated sulphonamides

88

What is the most common cause of vaginal bleeding in the mare?
Is any treatment required for this cause?

Varicose veins
Not usually

89

What might you give to an older mare to reduce orthopaedic disease?

NSAIDs

90

What should you pack in your car when going to a dystocia?

Sedation (+ ketamine?)
Clenbuterol/buscopan
LA (epidural)
Doxapram
Foaling ropes
Lubricant
Hibiscrub
Needles/syringes
Waterproofs

91

What should you check when arriving to a dystocic mare?

Restrain mare (Sedate? Twitch? Clenbuterol?)
Check mare not in shock/haemorrhaging
Clean perineum/arms
Ascertain presentation of foal
Vaginal exam

92

Can you remove a foal per vaginum if it is presented with all 4 feet pointing forward?

No, must do a C-section

93

What may happen if there is a complete uterine rupture in a pregnant mare? What should you do?

Foal may fall into abdomen and not be palpable in birth canal
Mare may fatally haemorrhage, or may develop fulminating peritonitis and fatal endotoxaemia
Extract foal and consider mare euthanasia

94

How do you diagnose a uterine rupture/tear?

Clinical signs
Rectal/vaginal exam
Ultrasound
Peritoneal tap

95

How do you treat a uterine rupture/tear in a pregnant mare?

Medical tx as for peritonitis
Exploratory laparotomy and repair for full thickness tears

96

How should you treat perineal laceration in a mare after foaling?

May heal without intervention
Lacerations which disrupt perineal anatomy should be repaired, esp if will alter perineal conformation. Repair surgically 4-6 weeks later when granulation has set in. Repair required for mare to conceive again
Give antibiotics/NSAIDs/tetanus

97

Why should you not repair 3rd degree perineal lacerations immediately?

Will break down

98

Urovagina is usually seen in which kind of mares?

Old, pleuriparous mares, often with pneumovagina

99

How can you confirm urovagina?

Cytology
Rule out ectopic ureter in young fillies
Improve BCS if thin

100

How can you surgically manage urovagina in the mare?

Caudal relocation of transverse fold of vestibule
Urethral extension
Uterine suspension (shorten broad lig of uterus -> elevates whole repro tract into the anatomy of a younger mare -> re-orientates the urethral orifice

101

When are cervical injuries usually sustained?

During parturition

102

How and when should you surgically repair cervical lacerations?

Perform surgery during di-oestrus, > 3 weeks post-partum
Retract caudally, suture with 3-layer closure

103

What causes delayed uterine clearance?

Endometritis
Post-mating persistent endometritis
Uterine suspension

104

How do you surgically fix delayed uterine clearance?

Uterine suspension:
Restoration of normal horizontal orientation of uterine horns
Improves uterine clearance and perineal conformation, may reduce urine pooling

105

How can you fix a blocked oviduct?

Prostaglandin-relaxes smooth muscle of oviduct, modulates oviductal transport

106

When do perineal lacerations occur in the mare?

During foaling in primiparous mares

107

Describe a first degree perineal laceration

Mucosal damage
Caslick/no surgery required

108

Describe a 2nd degree perineal laceration

Mucosa, submucosa and perineal muscles affected
Caslicks procedure and reconstruction of perineal body required

109

Describe a 3rd degree perineal laceration

Complete disruption of recto-vestibular shelf, perineal body and anus
Requires surgical repair, delay repair for 4-6 weeks for granulamatous tissue to form
One or 2 stage procedures

110

How do recto-vestibular fistulas occur? How are they fixed?

Penetration of foal's foot into rectum without progression to 3rd degree perineal laceration
Unsuccessful repair of 3rd degree perineal laceration
Repair surgically

111

What is the most common neoplastic disorder of the ovaries? Describe it

Granulosa cell tumour
Unilateral
Rarely metastasises
Good prognosis

112

What behaviour signs would you see in a mare with a granulosa cell tumour on her ovary?

Anoestrus/continuous oestrus
Stallion-like behaviour/aggression

113

How do you diagnose ovarian granulosa cell tumours?

Rectal exam (enlarged ovary)
Ultrasound (honeycomb appearance of enlarged ovary)
Endocrine tests (increased testosterone in 50%, increased inhibin in 85%, increased anti-mullerian hormone in 98%-this test is best!)

114

How do you treat ovarian granulosa cell tumours?

Ovariectomy, unilateral or bilateral
Can do laparoscopy (standing, GA), or laparotomy under GA, or colpotomy (incision through vagina)

115

How would you recognise a mare in dystocia?

Prolonged discomfort and straining
Straining without appearance of amnion
Appearance of amnion/head/limb but no further progress

116

How long should you give yourself to clinically examine a mare in dystocia?

15 mins

117

How should you clinically examine a mare in dystocia?

See what state mare is in (shock, haemorrhage) +/- sedation (xylazine)
Bandage tail
Clean perineum
Wash hands/anus/gloves
Lubricant

118

What are the 4 delivery options for a mare in dystocia?

Assisted vaginal delivery
Controlled vaginal delivery
C-section
Embryotomy

119

Describe an assisted vaginal delivery

Mare is conscious
Foal delivered using traction +/- ropes
Sedation and epidural if mare straining excessively

120

Describe a controlled vaginal delivery

Mare anaesthetised +/- HLs elevated (to allow foetus to move cranially into abdomen)
Foetus delivered per vaginum
Abdomen should be prepared for C-section at same time

121

When might you perform a terminal C-section?

Foal more important than saving mare
Chronic disease in mare
Deliver foal under anaesthetic then euthanise mare

122

When may uterine prolapse occur? How do you correct it?

Post dystocia/straining
Replacement under standing sedation/GA

123

When does uterine artery haemorrhage occur?
Give some clinical signs

Older mares
Colic and evidence of haemorrhagic shock

124

When may uterine torsion occur?
How do you diagnose?
How do you treat?

Rare, last 2 months gestation/at parturition
Colic/dystocia
Diagnose by rectal palpation-will feel 1 tight broad ligament
Correct surgically or non-surgically

125

When may uterine rupture occur?

Clinical signs evident 24-72 hours post-foaling
Treatment depends on size of tear

126

How do you correct uterine neoplasia?

Rare
Partial/total ovariohysterectomy
GA/standing laparoscopic techniques

127

How do you correct pyometra?

Rare
Drain uterine contents prior to surgery -> ovariohysterectomy (laparotomy +/- laparoscopy)

128

What mammary problems may occur in the mare?

Mastitis
Neoplasia

129

Which part of the mare repro tract does squamous cell carcinoma affect?
What is the prognosis?

Vulva and clitoris
Poor prognosis even with radical resection

130

When are varicosities worst in the mare?

Oestrus (increased blood flow)

131

When should the foetal membranes be passed after parturition?

Within 2 hours of parturition
Over 4 hours is considered abnormal

132

How do you treat retained foetal membranes?

Oxytocin
Broad-spectrum ABs, NSAIDs, flunixin for anti-endotoxic effects, tetanus cover

133

How do you treat metritis post-foaling?

ABs, NSAIDs, oxytocin, lavage

134

Give some clinical signs of hypocalcaemia post-foaling
How do you treat it?

Rare. Muscle fasiculations, recumbent, diaphragmatic flutter 'thumps'
Tx: Give calcium diluted in saline