18.3.2: Clinical reproduction

Question 1

When is the ideal age to have a first foal from a mare?

Answer 1

5-7 years
However it is often uncommon to breed at this age because the horse is being ridden

Question 2

Would you want to breed this mare? If not, why not?

Answer 2

• Hair coat suspicious for PPID
• Not a definite no to breeding but must be taken into consideration

Question 3

What health tests/ screens must be undertaken before a mare arrives at stud?

Answer 3

• Reproductive pathogens: Taylorella equigenitalis
• This is part of contagious equine metritis and detected via clitoral swab
• Every reputable stud requires this
• Other notifiable diseases should also be screened for in order to have good biosecurity as a stud farm

Question 4

How do you test for CEM/ Taylorella equigenitalis ?

Answer 4

Clitoral swab

Question 5

How sound does a mare need to be in order to carry a foal?

Answer 5

She must be pasture-sound at minimum

Question 6

Answer 6

• Sunken anus -> risk of faecal contamination, air being sucked in and chronic endometritis
• Possibility of urine pooling
• Vulval lips are not properly sealed
• Would manage this with Caslick’s procedure

Question 7

What structure might you look out for especially when scanning an older mare with no previous breeding history?

Answer 7

Endometrial cysts - these are more common in older mares

Question 8

Answer 8

1 - Corpus luteum
2 - follicles - could measure these
* Could grade uterine oedema - this is a 0/3
* This mare is in the luteal phase (dioestrus)
* Need to give the mare prostaglandin to lyse the CL

Question 9

What would you expect this mare’s cervix to feel like?

Answer 9

• This mare is in the luteal phase (dioestrus) and progesterone is dominating
• She would have a toned cervix

Question 10

Answer 10

• This mare has mutliple follicles (measure these)
• She also has uterine oedema (2/3)
• Her cervix would feel softer and be opening
• She is on day 16/17 of her cycle (early oestrus) -> scan every 1-2 days

Question 11

This follicle is 35mm. Thoughts?

Answer 11

• Uterine oedema 3/3
• Follicle acquires a tear-drop shape when close to ovulating -> not doing this yet
• Start to consider forcing ovulation by giving GnRH or hCG -> this would ensure ovulation in the next 24-48hrs

Question 12

What is lifespan of frozen semen?

Answer 12

• Frozen semen = very limited lifespan
• Must meet the egg within 6 hrs
• Could consider using one dose pre-ovulation and another post-ovulation
• Could use ovulation-inducing agents to induce ovulation at a specific time point, and scan mare repeatedly within that time frame

Question 13

A

Answer 13

32-40 hrs

Question 14

B

Answer 14

36-42 hrs

Question 15

How would you expect this mare’s cervix to feel?

Answer 15

Soft and dilated

Question 16

This is a post-insemination scan. What can you look for?

Answer 16

• There is a corpus haemorrhagicum on the ovary
• Could measure the amount of fluids/ consider oxytocin/ flush if 30mm or more/ endometrial swab and culture in case antibiotics needed

Question 17

What is the earliest we can detect pregnancy in the mare?

Answer 17

12-15 days

Question 18

Signs of oestrus in the mare

Answer 18

• Lifted tail head
• Discharge from the vulva
• Clitoral winking
• Behavioural changes (often considered more sassy)

Question 19

How do you treat post-mating endometritis?

Answer 19

• Uterine lavage
• Oxytocin
• Intra-uterine antibiotics

Question 20

What should you check at a post-insemination check?

Answer 20

• Quality of CL
• If there have been any secondary ovulations making twins a possibility
• Any signs of post-mating endometritis

Question 21

How long can fresh semen survive in the mare and when should she be inseminated in relation to ovulation?

Answer 21

• Fresh semen will survive at least 48hrs in the mare
• Insemination is performed before ovulation (12-36hrs perior to expected ovulation; use ovulation-inducing agents to time this)

Question 22

Which tends to lead to greater post-mating endometritis:
a) fresh/chilled semen
b) frozen semen

Answer 22

b) frozen semen

Question 23

This is a scan from 15 days post ovulation

Answer 23

• There is a healthy embryo here
• There could be an endometrial cyst or a second conceptus on the LHS -> see if it moves and monitor for growth
• Look for CLs and count them
• If unsure, rescan in the next 1-2 days

Question 24

A mare has become pregnant with twins and you need to crush one conceptus. What medication might you give the mare beforehand?

Answer 24

• Restraint her in stocks
• Chemical restraint: detomidine + butorphanol
• NSAIDs: flunixin or phenylbutazone
• Could consider buscopan to relax rectum but this will relax uterus as well