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Equine Final Year > Diagnostic Methods and Cycle Manipulation in the Mare > Flashcards

Diagnostic Methods and Cycle Manipulation in the Mare Flashcards

1
Q
  • 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?
A
  • Multiple Equine HV. 3 predominately causing these pustules which erode.
  • Transmitted venereally
  • See variety of adhesions as they age
  • Start as these vesicular lesions which can burst and erode
  • Mare will be sore and itchy
  • Lesions would be on stallion too
  • Transmission can be by stud and contamination of handler or material
  • This mare will be shedding virus
  • Actions: Isolate, don’t contaminate material, do not breed
  • Consequence – this local disease (doesn’t cause pregnancy failure)
  • If you are breeding – ensure no lesions at the time
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2
Q

What is the common diagnostic approach to a breeding exam?

A
  • History
  • Previous fertility
  • Consider venereal pathogens
  • General clinical examination

–Is she actually in oestrus or is she just showing odd signs?

  • Mammary
  • Perineum
  • Vulva, vestibule, vagina, cervix
  • Uterine palpation and ultrasound
  • Ovarian palpation and ultrasound
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3
Q

What information do we need in a breeding exam relating to the history? (7)

A

•Current Presentation

–Pregnant

–With a foal at foot

–Barren (in equine terms meaning bred last year but did not get pregnant (just referring to last year))

–With a specific problem

•Really important questions are:

–Age of mare

–Previous breeding history

  • Not pregnant
  • Early pregnancy loss – did it establish? Maintained to full term?
  • Abortion / stillbirth
  • Need to establish if the mare can carry the pregnancy all the way through

–If barren

  • What was the management last year?
  • Who was the Vet last year?
  • Number of years barren?
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4
Q

What do you look for on a general physical exam of a breeding mare?

A
  • Body condition
  • General observations

–Is she lame?

–Is she hairy?

  • Feet
  • Udder
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5
Q

What specific details do we need to know about the perineum? (7)

A
  • Long axis of the vulval should be vertical
  • Vulvar labia should be well apposed
  • No vulval discharge
  • No vulval lesions
  • Perineum should be intact
  • Anus should not be recessed
  • Normal vestibulo-vaginal seal

–Need to part vulval lips to establish this

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6
Q

What can be seen on the images?

A

A) Normal

B) Sunken anus – cranially which causes vaginal sloping = increased faeces contamination and wind sucking

C) Palpating pelvis

D) Vestibulo-vaginal seal – ring structure (open). Risk of gas aspiration into vagina. Predisposed to cervixitits

E) Coital exanthema

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7
Q

What can the HBLB codes of practice give us guidance on? (8)

A
  • Venereal transmitted bacterial diseases caused by the contagious equine metritis organism CEMO, Klebsiella pneumoniae and Pseudomonas aeruginosa
  • Equine Viral Arteritis - EVA
  • Equine Herpesvirus - EHV
  • Equine Coital Exanthema - ECE
  • Equine Infectious Anaemia - EIA
  • Dourine
  • Strangles
  • Artificial Insemination – AI
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8
Q

What is the HBLB?

A

•What they do.. specific guidelines (not a law or absolute, just the best thing to do) each year for specific categories of mare (walk in, resident etc) for:

–Taylorella equigenitalia (Contagious equine metritis organism [CEMO])

–Klebsiella pneumoniae (Capsule types 1,2,5)

–Pseudomonas aeruginosa (specific strains but not possible to type these in routine testing so all are therefore [incorrectly] assumed to be pathogenic)

These define number of swabs, where from and how may repeats

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9
Q

How do you swab for bacterial veneral pathogens?

A

–You need to swab the fossa and sinus

(and in some cases the uterus)

–You need Amies transport media (e.g. charcoal)

•Taylorella is a microphillic

–You need to send to Approved Lab

–Culture needs to commence within 48h

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10
Q

What is seen in these images?

A

Left - Fossa

Middle - Sinus

Right -

Sinus smegma

Squeezing clitoris and see the waxy material (smegma). This is what we are swabbing. Organisms live.

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11
Q

What are the bacterial venereal pathogens we swab for? (5)

Discuss the different isolates for 2 of the bacteria

A

•Certificates simply state:

–Taylorella equigenitalia .. was / was not isolated

–Klebsiella pneumoniae .. was / was not isolated

–Pseudomonas aeruginosa.. was / was not isolated

  • A separate section may indicate for Klebsiella what the capsule type was (remember capsule types 1,2,5 are the only ones that are pathogenic). Many types where some are venereal and some are not. The lab can easily differentiate this. E.g. if you had capsule 13 it wouldn’t stop you breeding.
  • There will be no designation for strain of Pseudomonas. Some which are known venereal and some are environmental contaminants. Two sorts pathogenic and not – we cannot isolate which one we have.
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12
Q

What is the action if contagious equine metritis is isolated?
1. In mares prior to covering

  1. Stallions prior to covering
  2. Mares and stallions after covering
A

•In mares prior to covering

–Isolate and treat infected mares

–Notify owners of mares

•Stallions prior to covering

–Isolate and treat

–Notify owners of mares

•Mares and stallions after covering

–Cease covering

–Check all mares implicated in the outbreak

–Do not cover until 3 negative swabs each at least 2 days apart

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13
Q

What do mares need to be serologically negative to?

A

•Normally ensure mare is serologically negative to Equine Viral Arteritis (or vaccinated for this)

N.B. EVA is notifiable by law in the UK

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14
Q

How is EVA transmitted? (2)

A

•Transmitted both via respiratory tract route and also venereally (including chilled semen)

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15
Q

What are the signs of EVA? (4)

A

•Classic disease is flu-like but with significant conjunctivitis, (pink eye) focal dermatitis, limb and ventral oedema

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16
Q

What is the effect of EVA on pregannt mares?

A
  • Pregnant mares that get infected may abort (abortion may relate to degree of immunity or pathogenicity of virus strain)
  • Aborted fetuses appear partialy autolysed (unlike fresh fetuses in EHV) however still need appropriate pathological examination
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17
Q

When is EHV 1 vaccinated for?

A

planned for month 5, 7 and 9 of pregnancy e.g. Equip EHV 1,4

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18
Q

What do horses returning to the UK need to be serologically negative for?

A

EIA

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19
Q

Why do we undertake uterine swabs?

A

•Undertaken for bacterial venereal pathogen screening – we will do this based on previous history ; high or low risk. High risk – likely to have had a venereal pathogen previously so is recommended to uterine swab.

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20
Q

Why are uterine swabs undertaken? (3)

A

Endometritis:

–For endometrial cytology as part of detection of endometritis

–For endometrial bacteriology in cases of endometritis to ensure appropriate antimicrobial selection

–For the detection of other pathogens (yeast / fungi – requires specific culture medium)

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21
Q

When should we undertake a uterine swab?

A

•Uterine swabs are often taken during oestrus (this is HBLB guidance): but we will talk more about this later since probably collection in the luteal phase would be more appropriate

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22
Q

How do we examine the vagina and what do we look for? (2)

A

Digital, Speculum or Endoscopic examination of vagina and cervix

  • Confirmation of normality and estimation of stage of the cycle
  • 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

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23
Q

What can be seen on the below pictures:

A

A) Dioestrus – cervix hard and narrow

B) Oestrus – cervix large and oedematous

C) Cervicitis

D) Cervical adhesions

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24
Q

What is seen on rectal exam of mare? (4)

A
  • Confirmation of normality
  • Confirmation of cyclicity and stage of cycle
  • Confirmation of non-pregnancy
  • Evidence of gross pathology

–e.g. Absence of, or large uterus

–e.g. Inactive ovaries, or large ovaries

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25
Q

What are the 2 possile reasons for 2 small ovaires?

A

. Mare is acyclical

  • Anoestrus (cervix/uterus will be intermediate in size/tone)
  • Prepubertal (cervix/uterus will be intermediate in size/tone)
  1. Mare is abnormal (e.g. Turners Syndrome) (all tubular genitalia are small)
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26
Q

What are the 2 reasons for 2 medium sized ovaries?

A
  1. Mare is in the ovulatory period (cervix/uterus will be either oestrogen or progesterone dominated or intermediate in size/tone)
  2. Mare is pregnant
  • Cervix/uterus likely to be progesterone dominated in early pregnancy
  • Cervix/uterus likely to be oestrogen dominated in late pregnancy
  • Uterine swelling and the size of this will be broadly diagnostic of the stage of pregnancy
  • Foal normally not palpated until after day 80
27
Q

What are the 2 possible reasons for Two medium-sized ovaries with ‘something’ palpable on one (or both)?

A

Mare is in ovulatory period

  • The ‘something’ is most likely to be a follicle or a corpus haemorrhagicum
  • If follicular and mare in oestrus the cervix/uterus will be oestrogen dominated
  • If CH the cervix/uterus will be intermediate - the structure may be painful
  • Ultrasound may be needed for accurate diagnosis
  • Remember many mares have palpalable follicles during mid to late dioestrus – these mares have a cervix/uterus that is dominated by progesterone and the mare will not show to the stallion
  1. Mare is pregnant
  • Cervix/uterus likely to be progesterone dominated in early pregnancy
  • Cervix/uterus likely to be oestrogen dominated in late pregnancy
  • Uterine swelling and the size of this will be broadly diagnostic of the stage of pregnancy
  • Foal normally not palpated until after day 80
28
Q

What are the 4 possible reasons for 2 large ovaries?

A

. Mare is in the transitional phase – often lots of follicles in the spring time.

•Cervix and uterus may be largely oestrogen dominated: Consider time of year

  1. Mare is pregnant
  • Marked enlargement of the ovaries may occur under the influence of eCG (causes follicular growth and lutenisation)
  • Ovarian size is increased from days 40 to 100 of pregnancy
  • Cervix/uterus likely to be progesterone dominated
  • Uterine swelling and its size will be broadly diagnostic of the stage of pregnancy
  • Foal normally not palpated until after day 80
  1. Mare is pseudopregnant
  • Pregnancy loss after formation of endometrial cups (pseudopregnancy type II)
  • Features consistent with pregnancy at this stage with the absence of the uterine swelling
  1. Mare has prolonged dioestrus
  • Persistence of CL can result in xs follicular growth despite the presence of luteal tissue
  • Both ovaries may have obvious follicular structures palpalable however the cervix/uterus are progesterone dominated
29
Q

What is this?

A

Large ovaries with follicles typical of spring transitional period

30
Q

What is this?

A

Large ovaries with luteinised follicles typical of pregnancy after endometrial cup formation

31
Q

What are the 2 possible reasons for One very large ovary and one normal ovary?

A

. Mare is likely to have an ovarian haematoma or luteinised follicle

  • Most commonly found at the end of the breeding season
  • Commonly occur as an abnormality of ovulation but there is subsequent luteinisation so that the cervix/uterus are progesterone dominated
  1. Mare may have an early (small) ovarian tumour
  • Interestingly, mares with small ovarian tumours are infrequently diagnosed
  • May be producing testosterone, oestrogen or progesterone with characteristic influence on cervix/uterus and subsequent effect on cyclicity and behaviour
32
Q

What is the reason for One very large ovary and one very small ovary?

A

Mare is likely to have ovarian tumour

  • Most tumours are endocrinologically active and produce characteristic effects on the cervix/uterus
  • High hormone concentrations result in a negative feedback effect and subsequent reduction in the size of the contra-lateral ovary
  • Behavioural changes are typical depending upon the primary hormone produced by the tumour
33
Q

What do we look for on U/S of the uterus? (4)

A
  • Confirmation of normality
  • Confirmation of cyclicity and stage of cycle
  • Confirmation of non-pregnancy
  • Evidence of gross pathology
34
Q

What can be seen here?

A

Wheel / dart-board appearance of normal uterine oedema noted during oestrus

Oedema in the endometrium – intertwining dark and white

35
Q

What can be seen here?

A

Large volume uterine fluid in case of pyometra. Pus in the mare uterus.

36
Q

What do we look for on U/S of the ovaries? (3)

A

•Confirmation of normality

(refer to rectal palpation material on previous slides)

•Confirmation of cyclicity and stage of cycle

–Remember follicles are fluid-filled (anechoic), CHs are generally bright white (but may be cavitated) and CLs are echogenic

•Evidence of gross pathology

37
Q

What is seen here?

A

Normal follicle pointing, collapse and formation of CL (CH)

POF – pre ovulatory follicle

EF – Emptying follicle

38
Q

What can be seen here?

A

Anovulatory luteinised / haemorrhagic follicle commonly seen at end of breeding season in older mares

39
Q

•For example a mare that has been barren for more than 2 seasons that was served at a professional stud with appropriate veterinary management, which presents to you with fluid within her uterus

What are the affects of this? (4)

A

–HAS got chronic endometrial disease

–WILL have a poor prognosis for getting pregnant

–WILL have a poor prognosis for taking a foal to term

–If you attempt to manage this mare it WILL cost a lot of money

40
Q

What “additional tests” are there for a mare breeding exam? (5)

A
  • Endometrial Cytology
  • Endometrial Microbiology
  • Endometrial Biopsy
  • Uterine Endoscopy
  • Karytopye
41
Q

How do we cary out endometrial cytology and what do we look for?

A
  • Use guarded swab technique.
  • Strict asepsis, technique as before and staining with common to use Diff Quik staining
  • Identify presence of endometrial cells (to show suitable sample), and then evaluate the number of neutrophils per medium power field (x400 = x40 lens and x10 eyepiece)

–Some neutrophils is normal

–More than 5 neutrophils per MPF (medium power fieild, 40x lens and 10 eye piece) is classified as abnormal - not 100% accurate can depend on sample thickness

–May also identify pathogens in some cases

42
Q

What can be seen here?

A

Left - Normal endometrial cytology

Middle - Acute endometritis with many neutrophils

Right - Yeast-related endometritis (induced by long term antibiotic administration)

43
Q

What 4 things for you look for on endmetrial bacteriology?

What is the most common pathogen?

A
  • Aerobic culture
  • Microaerophilic culture
  • Anaerobic pathogens
  • Yeast / fungi

The most common pathogen is Streptococcus zooepidemicus

(aerobic culture)

44
Q

Why would we do an endomerital biopsy? (7)

A
  • Endometrial biopsy is also often taken in attempt to establish a prognosis: although you really should know based on your history and clinical examination
  • 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
45
Q

What is the technique for endometrial biopsy?

A
  • Restrain mare, bandage tail, strict asepsis
  • Manually dilate cervix then pass sterile basket-jawed forceps into the uterine lumen
  • Position forceps so that cutting jaw faces dorsally: open the jaws push onto endometrium, close the jaws and give a ‘tug’ (may need to be forceful)

–It is virtually impossible to rupture the uterus

–Haemorrhage is rarely significant

–The mare is not aware of the procedure

•Sample put into adequate volume of Bouin’s fluid

46
Q

Endometrial biopsy is useful for diagnostic aid and some aspect of prognosis. What changes are there and how can we classify? (3)

A

–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)
47
Q

What is this?

A

Marked neutrophil infilatration

48
Q

What is this?

A

Fibrosis and dilated glands

49
Q

What are the 4 classifications for endometrial bopses and how do we classify?

A

•Category I

–No pathological changes and mare should have normal fertility

–Estimated foaling rate = 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 fetal development

–Estimated foaling rate = <10%

–Clinical history will have given guidance. Now on examination; probably find fluid which will keep coming back. Underpinning reasons – poor conformation; sloping vulva – vaginitis or cervicitis?

50
Q

How do we do uterine endoscopy?

A
  • First ensure the mare is not pregnant
  • Following strict asepsis placement of flexible endoscope into vagina and through the cervix
  • Direct visualisation and detection of congenital or acquired abnormalities
  • Cutting or diathermy may be useful for management of some clinical conditions
51
Q

What can be seen here?

A

A) Normal endometrium

B) Uterine adhesion

C) Endometrial cysts

52
Q

What is karyotype most likely to be used for? (2)

A

–Clinical suspicion of problem eg:

  • Clitoral enlargement
  • Infantile vulva and vagina
  • Small uterus
  • Small inactive ovaries

–In mare that should have reached puberty and is not within the winter anoestrus period

•Remember mares just out of training may not be cycling

53
Q

What is the normal karyoptype?

A

64XX

54
Q

What is an occasional cause of infertility seen in karyotype?

A

•Spontaneous aneuploidy is an occasional cause of infertility

–One of the common abnormalities is 63XO a condition referred to a Turner’s Syndrome

  • Tubulogenital tract normal but small, ovaries very small and inactive
  • Surprisingly may show irregular non-cyclical oestrous behaviour

Other abnormalities include 62XX and XXY

55
Q

What is the normal repro biology for a horse?

A
  • Seasonally polyoestrus
  • Normal breeding- May to October

–Early spring: mares have transitional period with follicles that don’t ovulate (ovaries can be very large – 2 large ovaries)

–Late autumn: cyclicity ends with silent or anovulatory heat (some pones cycle throught winter)

•But, the required breeding season is mid-Feb to July because registered birthdate is 1st January

56
Q

What is the clinical presentation of anoestrus?
Looking at: Ovaries, uterus, vagina and cervix?

A

–Ovaries: small and hard, small follicles

–Uterus: flaccid

–Vagina: pale and dry

–Cervix: small and closed

57
Q

What is the clinical presentation of transitional?
Looking at: Ovaries, uterus, vagina and cervix?

A

–Ovaries: larger – soft follicles grow and regress

–Uterus: transitional

–Vagina: like anoestrus

–Cervix: like oestrus

58
Q

What is the clinical presentation of oestrus?
Looking at: Ovaries, uterus, vagina and cervix?

A

–Ovaries: medium – something palpable (follicle -> CH)

–Uterus: large and oedematous

–Vagina: moist and hyperaemic

–Cervix: broad and soft

59
Q

What is the clinical presentation of Dioestrus?
Looking at: Ovaries, uterus, vagina and cervix?

A

–Ovaries: medium – early CH feels like follicle, CL not palpable

–Uterus: small and tonic

–Vagina: pale and dry

–Cervix: hard and narrow

60
Q

What is the optimum time for mating?

A
  • Mares ovulate a secondary oocyte which is immediately fertilisable but remains viable for only 12 hours after ovulation
  • Optimum mating in normal mares is 24 to 48 hours before ovulation
  • The game is therefore to predict when ovulation is going to occur

–Signs of oestrus

–With ultrasound

61
Q

Manipulation of Cyclical activity in the Mare What Do I need to Know i the mare?

A

•Mare

–Seasonal breeding and transitional phase

•Light, progesterone, GnRH

–Hastening ovulation in mares that are in oestrus

•GnRH, LH-like

–Inducing return to oestrus in the breeding cycling

•Prostaglandin

62
Q

What is the problem of the transitional period?

A
  • Mare not expecting to be cycling but it is required to have a foal born early in the year because of January 1st registration date
  • Mare may be in anoestrus (suppression by melatonin) but ultimately enters transitional period
  • Signs of transitional period

–Mare has follicles that grow and regress (either not enough LH or LH-receptors) but don’t ovulate

–Ovaries may be large, follicles may be detected

–Oestrous behaviour is usually present

–Mare may stand to be bred

–However does not ovulate and oestrous behaviour may be present weeks later

  • This is normal and the mare will ultimately ovulate
  • Some mare owners continue to serve whilst mare stands (may be served every other day for weeks)

–This may contribute to increased bacterial load and be a problem for mares predisposed to endometritis

•The follicle that ovulates may be difficult to predict so sometimes despite best efforts everyone is fed-up and the mare does not get bred at the correct time

63
Q

•Since the required breeding season starts on approximately 15th February the best plan is to enhance the onset of the transitional period and then to attempt to shorten the transitional period

How do we do this?

A

•This is done by:

–Providing 16hrs artificial light and additional nutrition from 1st December

•Some clinicians also adminsiter GnRH agonists at this time but efficacy is unproven

–Once the mare is within the transitional period (follicles greater than 2.5 cm in diameter) progestogens are administered to suppress the release of LH

  • Normally Altrenogest (Regumate) is given in feed for approximately 10 days
  • Follicles continue to grow during progestogen treatment
  • When follicles reach 4.5 cm progestogen treatment stops and there is a surge release of LH which induces ovulation

–Some clinicians also administer GnRH at this time to enhance the LH release

64
Q

What 6 things can we use to manipulate the mare cycle?

A

•Light

–Would need melatonin antagonist (not available) to stimulate oestrus

  • Daylight is effective if day-length is extended from December onwards
  • GnRH Agonists

–Short-term in action (e.g. buserelin [Receptal] injection or deslorelin [Ovuplant] implant) causes stimulation of LH and FSH release

  • Hastening of ovulation within normal oestrus
  • Hastening ovulation as part of synchonisation / induction regimes

N.B. Oestrus Prevention

•GnRF + adjuvant

–Two doses 4 weeks apart stimulates an immune response to GnRF

–Oestrus suppressed for 3-6 months

–Marketed as Equity (Pfizer) only available in Australia

•hCG

–Endogenous LH (hCG [Chorulon]) causes final maturation of follicles

  • Attempts to induce ovulation in animals that are in oestrus
  • To hasten ovulation in AI regimes (i.e. ensure ovulation occurs when expected)
  • Progestogens

–Exogenous progestogens (altrenogest [Regumate]) causes suppression, storage of gonadotrophins and surge release when stop progestogen

  • Used as method of inducing/synchronising oestrus by administration and withdrawal of the product
  • Prostaglandins

–Exogenous prostaglandins causes lysis of the corpora lutea although early CLs are usually not responsive

  • Return to oestrus (synchronisation?)
  • Treatment of pyometra ?
  • Ecbolic effect

Equine Final Year (102 decks)

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