18.3.3: Mare reproduction

Question 1

Answer 1

2 is the uterine horn
(Position A on the schematic)

Question 2

Answer 2

• There is anechoic oedema fluid underneath the endometrial folds
• Classic “wheel” appearance
• This mare is in oestrus/transitional phase

Question 3

Answer 3

• Longitudinal scan of body of uterus
• Fluid with echogenic particles
• Physiological if mated in the last 4 hrs; if any longer than that, likely to be mating-induced endometritis
• Only time you see free fluid in mare’s uterus = immediately after mating
• Sperm that are going to fertilise egg end up in the fallopian tubes very quickly (like within 15 mins)

Question 4

Answer 4

• These are endometrial cysts
• They are thin-walled and fluid filled
• They are common in older ones
• These ones are considered significant - may prevent the conceptus moving around the uterus

Question 5

Answer 5

• This shows an ovary with multiple medium-sized follicles
• There are obvious dominant follicles
• This mare is in the transitional phase, but we want to breed her soon
• Can use GnRH if large enough -> force follicle to ovulate
• Or could use progesterone for 10 days- 2 weeks -> there is a negative feedback effect and big upregulation when we take it away

Question 6

What is the purpose of putting a mare under lights?

Answer 6

• Mares are long day breeders
• Need to fool the mare into thinking it is spring so put her under lights in Jan

Question 7

Answer 7

• Very large ovary = probably haemorrhagic follicle, seen at the beginning and end of a breeding season
• Neoplasia is a possible differential, but is less likely because a tumour would have a negative feedback effect on the other ovary
• The mare is not pregnant - she didn’t ovulate
• Give her time - it is spring - the next cycle or the one after that will probably be normal