Foaling & Post-partum

Question 1

How can foaling be predicted?

Answer 1

• Physical changes of mare
• Foal prediction test kits
  
  • measure milk calcium concentrations
  • Foal Watch Test
    
    • <200ppm 99% chance mare will not foal in 24hrs
    • >200ppm:
      
      • 98% mare will foal within 72hrs
      • 84% mare will foal in 48hrs
      • 54% mare will foal in 24hrs
  • Predict-a-foal - milk test strip
  • Milk electrolyte inversion
  • pH of milk
    
    • pH >6.4 has negative predictive value of 99.4% mare will not foal w/in 24 hrs
    • pH<6.4 has a positive predictive value of 54.2% mare will foal w/in 24hrs

Question 2

How many stages are there to foaling? how long do they last?

Answer 2

• Stage 1: 30 min to several hours
• Stage 2: 20 minutes (10-40)
• Stage 3: 60 minutes (30 min - 3hrs)

Question 3

What happens during the first stage of foaling?

Answer 3

• Mare is Restless, tail swishing, mild colic, sweating, stretching, spontaneously milk
• Increasing intensity and frequency of uterine contractions
• Fetus re-orients itself
• Cervical dilation
• Ends with rupture of chorioallantois

Question 4

What happens during stage 2 of foaling

Answer 4

• Begins with rupture of the chorioallantois
• Mare may get up and down
• Forceful abdominal and diaphragmatic contractions
• Appearance of amnion covered limbs through the vulva
• Ends with expulsion of fetus

Question 5

What happens during stage 3 of foaling?

Answer 5

• Begins once the foal is delivered
• beginning of uterine involution
• Uterine contractions
• mild-moderate colic signs
• Ends with passage of fetal membranes

Question 6

What is “red bag”

Answer 6

• Premature placental separation
• Emergency
• Requires prompt action - manually rupture
• Observe chorion at vulva
  
  • reddened velvet-like appearance

Question 7

What foal orientation is ideal for parturition

Answer 7

• Presentation:
  
  • spinal axis of fetus to that of the dam and portion entering the pelvis
    
    • longitudinal or transverse
    • cranial or caudal
• Position:
  
  • dorsum of the fetus (or head if transverse) to the quadrants of the maternal pelvis
    
    • sacrum, right ilium, left ilium, or pubis
• Posture:
  
  • Fetal extremities (head, neck, and limbs) to the body of the fetus
    
    • flexed, extended, retained beneath or above
    • postural abnormalities are the most common cause of dystocia

Question 8

What is dystocia in mares?

Answer 8

• Emergency
• Difficult or prolonged foaling
  
  • once the mare’s ‘water breaks’ amnion or fetal parts should be visible through the vulva within 5 minutes
  • Advances should be evident every 5-10 minutes
  • Foal should be delivered w/in 20-30 minutes
• Uncommon: 4% in TB up to 10% in draft breeds

Question 9

What are the causes of dystocia? fetal or mare origin

Answer 9

• Fetal origin:
  
  • Abnormal posture, presentation, position **
  • Hydrocephalus
  • Contracted foal
  • Fetal oversize
• Mare origin:
  
  • Maternal immaturity: small pelvis
  • Malformed pelvis
  • Cervical adhesions
  • Uterine torsion
  • Ventral ruptures
  • Uterine inertia or fatigue
  • Premature placental separation
  • Tumors
  • twins

Question 10

How is Dystocia managed?

Answer 10

• Goal is to deliver the foal and preserve the mare’s fertility
• Assisted vaginal delivery
  
  • Mutation: manipulation of the fetal etremities, together with correction of any positional abnormalities such that vaginal delivery may proceed
    
    • Aseptic. +/- sedation or epidural, Lubrication, Repel the fetus, do not force the fetus
• Controlled vaginal delivery
• Partial fetotomy
• Cesarean section

Question 11

What is Uterine Involution? process?

Answer 11

• Return of uterus to normal, non-pregnant siz/function
• Process:
  
  • Postpartum: high concentrations of oxytocin and PGF_2a stimulate uterine contractions
  • Estrogen contractions start to rise as follicular recruitment start
  • Decrease in uterine size
    
    • uterus palpable w/in 3 days
    • Pregravid size in 23-32 days
  • Histologically:
    
    • Endometrial gland dilation is absent by day 4
    • Luminal epithelium is intact between days 4-7
    • Infiltration of inflammatory cells resolved by day 12
    • Normal pregravid histology by day 14

Question 12

What is ‘Foal Heat’

Answer 12

• First estrus that occurs after foaling
• Mares, usually come in to estrus 6-8 days postpartum
  
  • ovulation occurs around 10 days (as early as 7-8 or as late as 14-15)
• Conception rates 10-20% lower especially if bred/ovulate prior to day 10
• May not ovulate again, if early and not under lights
• Mare may not exhibit signs of estrus due to the foal
• If bread prior to day 25 post partum, may advance the mare’s calendar

Question 13

What are postpartum disorders of the mare?

Answer 13

• Retained fetal membranes
• Toxic metritis
• hemorrhage
• uterine prolapse
• mastitis
• trauma
• perineal laceration
• recto-vaginal tear
• large colon volvulus

Question 14

What are retained fetal membranes? why does it occur? what affects on the mare?

Answer 14

• Failure to expel fetal membranes w/in 3 hrs of parturition
• 2-10%
  
  • probability increases w/ dystocia, placentitis, abortion, fescue toxicity
• More common in the nongravid horn
• Sequelae
  
  • Delayed uterine involution
  • Metritis
  • Septicemia
  • Endotoxemia
  • Laminitis
  • Death
• Dx:
  
  • membranes present > 3hrs
  • Portions may be retained
    
    • examin the integrity of the fetal membranes once they are expelled
  • assume membranes are retained if not found

Question 15

What are the treatments for RFM?

Answer 15

• Burns Technique
  
  • distension of the chorioallantoic space with 8-12L saline
  • Ligate or zip tie the membranes to keep the fluid w/in the cavity
  • Stretches the uterus and cervix
    
    • induces oxytocin release and separation of the microvilli
  • Fetal membranes expelled within 30 minutes
  • Fetal membranes must be fully intact
• Oxytocin
  
  • 50-100 IU added to 500ml saline
    
    • IV slow over 30 min
  • Or Bolus: 10-20 IU IM (or IV) repeated every 2 hrs until expulsion
• Broad spectrum antibiotics
• NSAIDs
• Tetanus prophylaxis
• Uterine lavage 1-2x daily for 2-3d after expulsion
• Steps to prevent laminitis