Parturition in the Mare Flashcards
Prepartum considerations
- suitable location for delivery
- frequent observation
- vaccination status of mare
- remove caslick
Prepartum changes in the mare
- vulvar laxity
- vulvar edema
- relaxation of pelvic ligaments
- udder enlargement (last 2 weeks)
- change in amount and character of secretions
- waxing of teats
Colostrum
Secretions change from thin straw colored to milky white
- thick and viscous
- can be yellow or orange
Changes in _____ are related to fetal readiness and maturation
Colostral electrolytes
Stage 1
30 min to 4 hours
- prepartory phase
- restless, mild colic, urinates often, up and down, swish tail
- associated with uterine contractions
- foal rotation
Stage 2
20-30 minutes
- fetus and placenta against cervix
- ferguson reflex
- cervix dilates
- chorioallantois ruptures and allantoic fluid escapes
- fetus passes into birth canal
- abdominal contractions
- feet observed (covered with amnion) by 5 min
- nose at level of carpi
- amnion ruptures
- foal is delivered within 15 mintues
Stage 3
Passage of fetal membranes
- placenta expelled within 3 hours
Indications for induction
- convenience
- permits professional assistance
- research and teaching situation
- catastrophic injury to mare
- history of red bag
- neonatal isoerythrolysis
- previous RV tears
- ventral rupture
Criteria
- verifiable gestation length of 335 days
- presence of pre-foaling colostral electrolytes (Ca, Na, K)
- cervical softening
- normal presentation, position, posture
- fetal readiness for birth is paramount
Gestation length
Variable, 320-365
- mature in last 5-10% of gestation
- narrow window of neonatal viability
- mares foaling in early spring will have longer gestations
_______ is the best indication of fetal readiness
Colostrum electrolytes
- calcium rises just before delivery
- 200 ppm, 40 mg/dl, 10 mmol/L
- inversion of Na: K ratio
When to test milk electrolytes
Begin testing 10-14 days prior to expected foaling date (335-340)
- if no breeding date, then begin when small amount of fluid can be obtained w/o effort
- once a day as long as CaCO3 is <100 ppm
- thereafter 2x daily
- values rise quickly before bith
- always test late in afternoon or early evening
- most mares foal at night (12-3 am)
Milk electrolyte interpretation
- if 1st value >200 ppm: 51% will foal within 24 hrs, 84% in 48, 97% in 72 hrs
- if value is between 300-500ppm: is ready to foal now
- value less than 200 ppm: 99% will not foal in next 24 hrs
Kit contraindications
- if mare has been exposed to fescue, will make it difficult to interpret (artificially high or low numbers)
- use only distilled water: some hard water will influence results
- slight increase in mastitis with frequent testing
Cervical readiness
Palpate cervix, ascertain softness
- manually dilate the cervix for a shorter delivery (cytotec tablets)