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MODULE 19 - Reproduction and Fertility > REPRODUCTION - Equine Pregnancy and Parturition > Flashcards

REPRODUCTION - Equine Pregnancy and Parturition Flashcards

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1
Q

What is maternal recognition of pregnancy?

A

Maternal recognition of pregnancy is the prevention of luteolysis to allow for continued progesterone production to maintain pregnany

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2
Q

How does maternal recognition of pregnancy occur in the mare?

A

In the mare, the movement of the embryo around the uterus triggers a currently unknown hormone which prevents secretion of prostaglandin F2α secretion

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3
Q

When does the embryo enter the uterus in the mare?

A

The embryo enters the uterus 6 days post ovulation

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4
Q

When does the embryo undergo fixation in the uterus?

A

The embryo will no longer be motile and undergo fixation at day 16 post ovulation

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5
Q

Where do embryos always fix in the mare?

A

Embryos always fix at the base of the uterine horn

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6
Q

What produces progesterone to maintain pregnancy in the mare?

A

The primary corpus luteum will produce progesterone. At 35-40 days gestation, the mare will produce additional follicles on the ovaries which will eventually transition to secondary corpus lutea and produce progesterone. Furthermore, at over 60 days of gestation, the placenta will also produce progesterone to maintain pregnancy in the mare

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7
Q

What are endometrial cups?

A

Endometrial cups are transient endocrine glands which invade the endometrium at around 35 - 40 days of gestation and produce equine chorionic gonadotrophin (eCG) until day 120 of gestation

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8
Q

What is the proposed function of equine chorionic gonadotrophin (eCG)?

A

Equine chorionic gonadotrophin (eCG) has LH-like activity and promotes the production of follicles and secondary corpus lutea allowing for elevated progesterone production to maintain the pregnancy between 35 to 120 days of gestation. Furthermore, eCG is involved in the maternal immunotolerance of foreign antigens produced by the foetus

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9
Q

(T/F) Endometrial cups can persist even after embryonic death or abortion

A

TRUE. Endometrial cups can persist to 120 days even after embryonic death or abortion and continue to produce equine chorionic gonadotrophin which can have effects on her oestrous cycle and make management challenging

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10
Q

What are the methods of pregnancy diagnosis in the mare?

A

Teasing
Vaginal speculum diagnosis
Oestrone sulphate
Progesterone
Equine chorionic gonadotrophin (eCG)
Transrectal ultrasound
Palpation

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11
Q

How can teasing be used for pregnancy diagnosis?

A

You can present the mare to a stallion when she would be due to come into oestrus again (16 - 20 days post ovulation) and see if she is receptive. If not, this can indicate she is pregnant

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12
Q

What are the limitations of teasing for pregnancy diagnosis?

A

Pregnant mares may exhibit oestrus behaviours resulting in a false negative
Presistent corpus luteum can result in a false positive
Early embryonic death can result in alteration of the oestrous cycle and a false positive

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13
Q

What is a sign of pregnancy on vaginal speculum examination?

A

Dry, pale, tightly closed cervix (however this is non-specific to pregnancy)

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14
Q

What is oestrone sulphate?

A

Oestrone sulphate is a hormone produced by the foetal gonads

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15
Q

When can oestrone sulphate be used for pregnancy diagnosis?

A

Oestrone sulphate can be used for pregnancy diagnosis over 60 days post ovulation, but labs recommend 90-100 days

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16
Q

What are the limitations of using serum progesterone levels for pregnancy diagnosis?

A

High serum progesterone levels are not specific to pregnancy and could be due to other factors (such as a persistent corpus luteum)

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17
Q

What are the limitations of equine chorionic gonadotrophin (eCG) levels for pregnancy diagnosis?

A

Endometrial cups can persist to 120 days even after embryonic death or abortion and continue to produce equine chorionic gonadotrophin resulting in false positives

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18
Q

What is the most commonly used method of pregnancy diagnosis in the mare?

A

Transrectal ultrasound

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19
Q

When can transrectal ultrasound be used for pregnancy diagnosis in the mare?

A

Transrectal ultrasound can be used 14-15 days post ovulation for pregnancy diagnosis in the mare

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20
Q

What can be detected on ultrasound at days 14 - 15 in pregnant mares?

A

Embryonic vesicle

Note the small white echos indicating it is a perfect sphere
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21
Q

What can be detected on ultrasound at days 25 - 30 in pregnant mares?

A

Foetal heart beat

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22
Q

What can be detected on ultrasound at days 45-50 days in pregnant mares?

A

Foetus (more obvious heartbeat and foetal movements)

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23
Q

What is the ultrasound schedule for pregnant mares?

A

14 days: Look for embryonic vesicle, count the corpus lutea and check for twins
16 days: Second twin check if necessary
28 days: Check for foetal heartbeat
45 - 65 days: Final check ± Foetal sexing

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24
Q

What can be an indicator to recheck a mare for twins on day 16?

A

If you count more than one corpus lutea during the first pregnancy check in the mare, this means more than one follicle has ovulated and there is an increased risk of twins

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25
When can palpation be used for pregnancy diagnosis in the mare?
Rectal palpation can be used over 30 days post ovulation for pregnancy diagnosis in the mare
26
What is a sign of pregnancy on palpation in the mare at 14 -15 days?
Increased uterine tone and a long, tightly closed cervix *(however this is non-specific)*
27
What is a sign of pregnancy on palpation in the mare at 25-30 days?
Bulge on palpation of the uterus
28
Which horse breeds are at increased risk of multiple ovulations and twins?
Larger horse breeds are at increased risk of multiple ovulations and twins *(particularly thoroughbreds)*
29
What are unilateral twins?
Unilateral twins is when both embryos are fixed in the same uterine horn
30
What are bilateral twins?
Bilateral twins is where each embryo is fixed in a different uterine horn
31
What should you do if you detect a twin on transrectal ultrasound *(day 14 - 15)*?
If you detect a twin on transrectal ultrasound, you should 'pinch' it using your hand or the ultrasound probe | This is the preferred and most successful technique ## Footnote Has to be done while they are mobile to prevent accidentally pinching both twins where they are fixed
32
How can you manage twins from 16 - 35 days gestation?
Prostaglandin *(abort pregnancy)* Transvaginal ultrasound guided puncture and aspiration McKinnon's oscillation technique
33
What is the main risk of transvaginal ultrasound guided puncture and aspiration of the twin?
There is still a risk of puncturing both twins with the needle
34
What is McKinnon's oscillation technique?
McKinnon's oscillation technique is ultrasound guided grasping and oscillating (shaking) of the embryo until it detaches from the umbilical cord
35
How can you manage twins beyond 35 days of gestation?
Craniocervical dislocation Surgery Transcutaneous foetal injection
36
How long is gestation in the mare?
335 - 342 days
37
What can be used to indicate that the mare is readying for parturition?
'Waxing up' *(occurs 1 - 72 hours before parturition)* Foal alarms
38
What is 'waxing up' in mares?
'Waxing up' is the dripping of colostrum in mares
39
How long does stage 1 of parturition last in the mare?
30 minutes to 4 hours
40
What occurs during stage 1 of parturition in the mare?
The mare will become restless and may even exhibit mild colic. Uterine contractions will begin and the foetus will be forced agaisnt the cervix, progressing cervical dilation until the chorioallantois will rupture and foetal fluid will escape *(water breaks)*
41
How long does stage 2 of parturition last in the mare?
Less than 30 minutes
42
What occurs during stage 2 of parturition in the mare?
There will be uterine contractions and strong, visible abdominal contractions and the foetus will be expelled
43
How long does stage 3 of parturition last in the mare?
Stage 3 should occur within 3 hours
44
What occurs during stage 3 of parturition in the mare?
Foetal membranes should be completely expelled *(should occur within 3 hours post foaling)*
45
When should the foal stand post foaling?
The foal should stand within 1 hour post foaling
46
When should the foal begin to suckle post foaling?
The foal should begin to sucke within 2 hours post foaling
47
What is a red bag delivery?
A red bag delivery is where there is premature seperation of the chorioallantois placenta from the endometrium prior to the birth of the foal, resulting in a rapid decrease in oxygen to the foetus and hypoxia
48
What is uterine involution?
Uterine involution is when the uterus returns to it's normal state after pregnancy
49
How long should it take for the uterine involution in the mare?
It takes 7 days for the uterus to reduce in size, however it takes 14 days for histologic repair of the uterus
50
What can help to promote uterine involution in the mare?
Exercise can help to promote uterine involution in the mare
51
When would uterine torsion occur in the mare?
Uterine torsion usually occurs during the last trimester in mares, and rarely occurs during parturition
52
What are the clinical signs of uterine torsion in the mare?
Intermittent to acute colic Tachycardia *(sign of pain)* Depression *(sign of pain)* | Clinical signs depend on the degree of torsion
53
How do you diagnose a uterine torsion in the mare?
Rectal palpation
54
How do you treat a uterine torsion in the mare?
Rolling under general anaesthetic Standing flank laparotomy Ventral midline laparotomy Vaginal correction
55
How do you roll the mare to correct a uterine torsion?
Determine if the torsion is clockwise or anticlockwise on rectal palpation. Put the mare under general anaesthesia and place her in lateral recumbency *(right if clockwise torsion and left if anticlockwise torsion)*. Roll the mare opposite to the direction of the torsion and evaluate the position of the uterus using rectal palpation after every roll
56
What are the risks of rolling the mare under general anaesthesia?
Uterine rupture Uterine artery rupture Placental seperation
57
When can you do a vaginal correction to correct a uterine torsion in the mare?
You can only do a vaginal correction if the uterine torsion occured during parturition, as the cervix will be open, allowing you to correct the torsion vaginally
58
(T/F) You should always deliver the foal after correcting a uterine torsion
FALSE. Uterine torisions usually occur within the last trimester so it is best to leave the mare to deliver the foal naturally after correcting a uterine torsion
59
What are the two classifications of hydrops?
Hydroallantois Hydroamnion
60
What is a hydroallantois?
Hydroallantois is an excessive, progressive accumulation of fluid within the allantois
61
What is a hydroamnion?
Hydroamnion is an excessive, progressive accumulation of fluid within the amnion
62
What are the clinical signs of hydrops in the mare?
Abdominal distension Inappetence Dyspnoea Tachycardia Rupture of abdominal musculature and/or pre-pubic tendon ## Footnote Clinical signs associated with compression of structures *(i.e. the diaphragm, stomach etc.)*
63
How can you diagnose hydrops in the mare?
Rectal palpation Abdominal ultrasound
64
How do you treat hydrops in the mare?
Treatment of hydrops in the mare depends if she is close to parturition. If she is close to term you can induce the pregnancy and assist with delivery whilst controlling the drainage of fluid, making sure to give IV fluids at the same time to maintain blood pressure. If the mare is not close to term, abort the pregnancy and assist with delivery in the same way as you would a live foetus
65
When do ventral abdominal wall hernias or prepubic tendon ruptures tend to occur in mares?
Ventral abdominal wall hernias or prepubic tendon suptures tend to occur in late gestation as the gravid uterus becomes very large and heavy
66
What are the clinical signs of ventral abdominal wall hernias or prepubic tendon ruptures?
Ventral oedema Tachycardia Tachypnoea Difficultly moving
67
What is a key sign that the prepubic tendon has completely ruptured in the mare?
Udder will move cranially and the tuber ishium will be elevated
68
How can you diagnose ventral abdominal wall hernias or prepubic tendon ruptures in the mare?
Clinical signs Abdominal ultrasound
69
How do you manage ventral abdominal wall hernias or prepubic tendon ruptures in the mare prior to parturition?
NSAIDs Sling bandage Restrict exercise
70
How do you manage ventral abdominal wall hernias or prepubic tendon ruptures in the mare at parturition?
Monitor very carefully for signs of preparing for parturition, i.e. foal alarms etc, and induce parturition when optimal. Inducing parturition allows for you to have lots of people there to assist in the parturition
71
What is the prognosis for ventral abdominal wall hernias or prepubic tendon ruptures in the mare?
This is a very high risk pregnancy as the mare requires strong abdominal contractions for stage 2 of parturition. Due to the damaged abdominal musculature, the mare will be unable to assist in this stage of parturition
72
(T/F) You can breed mares with ventral abdominal wall hernias or prepubic tendon ruptures subsequently
FALSE. You should not breed mare with ventral abdominal wall hernias or prepubic tendon ruptures
73
What are the obstetrical principles for managing dystocia?
Plenty of lubricant Cleanliness Protect the uterus and cervix Have backup plans
74
What is the normal presentation of a foal at parturition?
Craniolongitudinal presentation Dorsosacral posture Extended head and limb position
75
What is the most common cause of dystocia in horses?
Dystocia in horses is typically due to abnormal posture of the foetus *(i.e. legs, head back etc.)*
76
Which factors should you assess when doing a clinical examination on a foaling mare?
Demeanour Assess pain TPR | You don't have time for a full clinical examination
77
Which factors should you assess when you begin to vaginally examine a foaling mare?
Is the cervix open or closed? What anatomy of the foal can you feel? Is the foal alive or dead? Can this foal be delivered vaginally?
78
What can you do to determine if the foal is dead or alive within the mare?
Movement Pinch the hoof Poke your hand in the mouth to test gag reflex Heart beat/pulse | Always assume alive if unsure
79
What can be done to manage dystocia in foals?
Assisted vaginal delivery (AVD) Controlled vaginal delivery (CVD) Caesarean section Foetotomy *(if dead foal)*
80
What is assisted vaginal delivery?
Assisted vaginal delivery is manual manipulation and gentle traction of the foal in a standing or recumbent, awake mare
81
What is controlled vaginal delivery?
Controlled vaginal delivery is where the mare is put under general anaesthesia, negating any uterine or abdominal contractions. You can use manual manipulation, gentle traction and can hoist up the mare's hindquarters to help reposition the foetus
82
What is the maximum amount of time you should attempt to vaginally manipulate a dystocia before doing a caesarean?
30 minutes
83
What can you use for traction in foaling?
Foaling ropes and chains | Maximum traction equivalent to 2 persons to prevent damage to the foal
84
(T/F) You can use a calving jack for foaling
FALSE. You should never use a calving jack for foaling as foals are not as ameanable to extreme traction and there is a high risk of injuring the foal
85
What can be used to reduce uterine contractions in the mare?
Epidural General anaesthesia Sedation Clenbuterol
86
(T/F) Never use oxytocin to aid dystocia in the mare
TRUE. Never use oxytocin to aid dystocia in the mare as dystocia in the mare is rarely caused by uterine inertia and is usually obstructive, and thus there is no indication for oxytocin and since oxytocin stimulates contractions, this can cause complications
87
What are retained foetal membranes in mares?
Retained foetal membranes in mares is where the placenta hasn't been expelled within 3 hours post-foaling
88
Which horse breeds are at increased risk of retained foetal membranes?
Heavy breed horses | i.e. Friesians
89
What are the risk factors for retained foetal membranes in mares?
Prolonged gestation Dystocia Placentitis Hydrops Induced delivery Caesarean section Uterine inertia *(rare in mares)*
90
What is the pathogenesis of retained foetal membranes in the mare?
Retained foetal membranes in the mare will rapidly progress to metritis which can result in sepsis/endotoxaemia, laminitis and even death
91
How do you treat retained foetal membranes in the mare?
Oxytocin Burns technique Umbilical vessel water infusion Uterine lavage Broad spectrum antibiotics NSAIDs Exercise Foal nursing
92
Why is oxytocin used to treat retained foetal membranes?
Oxytocin stimulates uterine contractions and can help to expel retained foetal membranes
93
How can you administer oxytocin to treat retained foetal membranes in the mare?
IM oxytocin every 4-6 hours or an oxytocin CRI
94
What is the Burns technique for retained foetal membranes?
The Burns technique is where you distend the chorioallantois with isotonic fluids using a tube, which may facilitate the release of the microcotelydons of the placenta from the endometrium and aid in the removal of the retained foetal membranes | This technique can only be used for intact foetal membranes
95
What is the umbilical vessel water infusion technique for retained foetal membranes?
You can take the umbilical cord and make a longitudinal incision into the vessel followed by advancing a stallion urinary catheter or foal stomach tube into the vessel. Hold the tube in place with you hand or cable ties and infuse water into the tube. The expansion of the vasculature can help to detach and expel the foetal membranes
96
What are the benefits of uterine lavage in managing retained foetal membranes? | Continue to lavage until the fluid runs clear
Stimulates uterine contractions Removes infection and debris Attracts neutrophils to the uterus *(helps to fight infection)*
97
When are antibiotics indicated for retained foetal membranes?
Broad spectrum antibiotics are indicated if the foetal membranes have been retained for beyond 6 hours
98
Why is exercise used in the treatment of retained foetal membranes?
Excercise releases endogenous oxytocin which will stimulate uterine contraction and help to expel the retained foetal membranes
99
Why is foal nursing used in the treatment of retained foetal membranes?
Foal nursing releases endogenous oxytocin which will stimulate uterine contraction and help to expel the retained foetal membranes
100
What are the clinical signs of metritis in mares?
Purulent, foul smelling vaginal discharge Pyrexia Anorexia Reduced milk yield Endotoxaemia/sepsis Laminitis ## Footnote Monitor the mare carefully and ice the hooves to try and prevent laminitis
101
What are the clinical signs of endotoxaemia/sepsis?
Profound depression Tachycadia Congested mucous membranes Toxic lines Brisk to prolonged CRT Pyrexia to hypothermia
102
How do you treat metritis in mares?
Broad spectrum antibiotics NSAIDs Oxytocin Uterine lavage Cryotherapy
103
What are the clinical signs of uterine or ovarian artery rupture?
Sudden collapse and death Tachycardia Sweating Trembling Winnying Restlessness Colic
104
How can you diagnose uterine or ovarian artery rupture?
History Clinical signs Rectal palpation of haematoma of the broad ligament Abdominal ultrasound Abdominocentesis
105
What is the main aim of managing a uterine or ovarian artery rupture in the mare?
You wan't to prevent a rise in blood pressure at this will worsen the haemorrhage and blood loss
106
How do you manage uterine or ovarian artery rupture?
Keep her calm Keep foal with the mare if possible *(to reduce stress)* NSAIDs Sedation IV fluid therapy Blood transfusion Naloxone Aminocarproic acid
107
Why is naloxone used in the management of uterine or ovarian artery rupture in the mare?
Nalaxone is an opioid antagonist which may lower blood pressure
108
Why is aminocarproic acid used in the management of uterine or ovarian artery rupture in the mare?
Aminocarproic acid is an antifibrinolytic drug which will prevent fibrinolysis and breakdown of any blood clots
109
What are the risk factors for uterine prolapse in mares?
Dystocia Abortion Retained foetal membranes
110
How do you manage a uterine prolapse in a mare?
Clean and lubricate the uterus gently with water and manually push it back into the body, or the mare can be anaesthetised and hoisted back in. Make sure to administer analgesia and antibiotics
111
Why do you administer oxytocin after correcting a uterine prolaspe in the mare?
In the mare, you administer oxytocin after correcting a uterine prolapse as the underlying pathophysiology of a uterine prolase in the mare is that it becomes flaccid, atonic and relaxed which allows it to prolpase. Oxytocin triggers uterine contractions which should help prevent this from recurring

MODULE 19 - Reproduction and Fertility (18 decks)

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