Repro

• What type of reproductive cycle do mares have?

  Seasonally polyoestrous
• When does normal breeding for mares typically occur?

  From May to October
• What happens during the early spring transitional period for mares?

  Mares have follicles that don’t ovulate and may have very large ovaries
• What is the typical breeding season required for mares?

  Mid-February to July
• What is the likely reproductive state of a mare in February?

  The mare is likely in anoestrus due to suppression by melatonin
• What are the signs of the transitional period in mares?

  Follicles grow and regress without ovulation, and oestrous behaviour is usually present
• 4 days post covering you are asked to examine a mare because she has an itchy vulva. Describe the lesions you see, What is the possible cause and what are the consequences and actions you should take?

  Multifocal crusting and raised lesions. Herpes virus is the likely cause, this is a venereal pathogen. This virus is likely being shed by the mare and hence this needs to be managed.

  
• What is the best plan to enhance the onset of the transitional period?

  Provide 16 hours of artificial light and additional nutrition from December 1st
• What is the purpose of administering progestogens during the transitional period?

  To suppress the release of LH
• What is the name of the progestogen commonly given to mares?

  Altrenogest (Regumate)
• What type of oocyte do mares ovulate?

  A secondary oocyte which is immediately fertilisable
• How long is the secondary oocyte viable after ovulation?

  12 hours
• What is the optimum timing for mating in normal mares?

  24 to 48 hours before ovulation
• What are the key ultrasound assessments for predicting ovulation in mares?

  • Follicle size
  • Follicle softening
  • Follicle wall thickening
  • Follicle haemorrhage
  • Follicle pointing
  • Reduction in uterine oedema
• with this image answer the following questions. What are the key features of the conformation that concern you? What are the likely consequences? What actions should you consider?


  Severely sunken anus which has moved the vulva dorsal to the pubis. The vulva is open which is likely to contaminate the vagina. Poor fertility risk due to endometritis (due to the high bacterial load at the vestibule), she also likely already has a pneumo-vagina. Surgical procedures e.g., caslick

  
• label the uterine endoscopic images

  A) normal endometrium

  B) uterine adhesion

  C) endometrial cyst

  
• What clinical signs may indicate the need for a karyotype analysis?

  • Clitoral enlargement
  • Infantile vulva and vagina
  • Small uterus
  • Small inactive ovaries
• What is the normal karyotype result for mares?

  64XX
• What is one of the common abnormalities associated with aneuploidy?

  63XO, referred to as Turner’s Syndrome
• What are the characteristics of Turner syndrome?

  • Tubulo-genital tract is normal but small
  • Ovaries are inactive
  • May show irregular non-cyclical oestrous behaviour
• What are other abnormalities associated with karyotype issues besides Turner syndrome?

  62XX and XXY
• A classification has been developed for endometrial biopsy, it demonstrates principles relating to prognosis…

  • Category I
  • No pathological changes and the mare should have normal fertility
  • Estimated foaling rate is 80-90%
  • Category IIA
  • Mild endometrial changes
  • 50 to 70% of these mares will foal
  • Category IIB
  • Moderate endometrial changes
  • Inflammatory changes severe enough to decrease fertility and may be accompanied by fibrosis
  • 20 to 50% of these mares will foal
  • Category III
  • Severe endometrial changes
  • Uteri may be incapable of supporting foetal development
  • Estimated foaling rate is under 10%
• Endometrial Biopsy is useful for diagnostic aid and some aspects of prognosis. Pathological changes include…

  • Acute inflammation
  • Neutrophil and occasionally eosinophil infiltration
  • Chronic infiltrative inflammation (repeated bouts of acute inflammation)
  • Mononuclear cells
  • Chronic degenerative changes
  • Layers of fibrous tissue around dilated glands
  • May also get dilated lymphatics (ageing)
• Biopsy can be taken at any time except pregnancy or when fibrosis of the cervix prevents it.

  • Mid-dioestrus is a good time as it minimises misleading histological changes
• Sensible indications for biopsy include…

  • Barren mares
  • Repeat breeder mares
  • Mares with early embryonic death or abortion
  • Anoestrus mares (during breeding season)
  • Mares requiring surgery of the genital tract
  • Pyometra or mucometra
  • Fertility evaluations (pre-purchase)
• how to perform an endometrial biopsy?

  • Restrain the mare, bandage the tail and use strict asepsis
  • Manually dilate the cervix then pass sterile basket-jawed forceps into the uterine lumen
  • Position forceps so that the cutting jaw faces dorsally: open the jaws push onto the endometrium, close the jaws and give a ‘tug’ (may need to be forceful)
  • It is virtually impossible to rupture the uterus and haemorrhage is rarely significant. Remember, the mare is not aware of the procedure
  • Sample put into an adequate volume of Bouin’s fluid
• endometrial microbiology is often not done as most cases are just streptococcus zooepidemicus
• What antibiotic preparations are licensed for uterine infusion and which are you going to use?

  None are licenced, but penicillin suspensions are often used off-license. Streptomycin is also used.
• when performing endometrial cytology, you want to evaluate the number of neutrophils per medium power field (x400 = x40 lens and x10 eyepiece)

  • Some neutrophils are normal
  • More than 5 neutrophils per MPF is classified as abnormal
  • May also identify pathogens in some cases
• Label the endometrial cytology images

  A) normal

  B) acute endometritis

  C) yeast-related endometritis

  
• Swabs for CEM are often taken during oestrus, however when not routine screening for CEM we need to consider what importance we should place on finding bacteria within the uterus when the cervix is open?

  • Swabbing during dioestrus means that any identification of any bacteria (as long as technique is sterile) is always significant.

  Always administer PG after swabbing: the ensures the mare returns to oestrus and usually microbiology results are back at an appropriate time
• ultrasound can be performed to image the…

  • Uterus to confirm…
  • Normality
  • Cyclicity and stage of cycle
  • Non-pregnancy (or pregnancy)
  • To identify evidence of gross pathology
  • Ovaries
  • To confirm
  • Normality
  • Cyclicity and stage of the cycle
  • Remember follicles are fluid-filled (anechoic), CHs are generally bright white (but may be cavitated) and CLs are echogenic
  • To identify evidence of gross pathology
• what does this image of the uterus indicate?

  A) oestrus

  
• what does this image of the uterus indicate?

  A) pyometra

  
• label the images of the ovaries

  A) normal follicle

  B) CL formation

  C) CL

  D) haemorrhagic follicle

  
• Rectal examination involves palpation of the cervix, uterus and ovaries for confirmation of normality, cyclicity and stage of cycle, confirmation of non-pregnancy and to identify evidence of gross pathology.

  • e.g. Absence of, or large uterus
  • e.g. Inactive ovaries, or large ovaries
• label the stages of the cycle on this image

  A) oestrus

  B) transitional phase

  C) anoestrus

  D) dioestrus

  
• what stage and pathology is seen on these cervixes?

  A) dioestrus

  B) oestrus

  C) adhesions

  
• Digital, Speculum or Endoscopic examination of vagina and cervix is used for confirmation of normality and estimation of stage of the cycle as well as to identify evidence of gross pathology

  • e.g. Presence of persistent hymen
  • e.g. Evidence of disease such as vaginitis or cervicitis
  • e.g. Evidence of trauma including scaring or deformation of cervix
  • e.g. Pooling of urine or pus in the vagina
• establish the disease and prognosis in this case. A mare that has been barren for more than 2 seasons that was served at a professional stud with appropriate veterinary management, presents to you with fluid within her uterus

  chronic endometrial disease - poor prognosis for getting pregnant and taking a foal to term. management of this mare is likely to cost a lot of money.