The Sick Foal Flashcards
What is failure of passive transfer? How is it treated?
failure of a foal to obtain maternal antibodies from colostrum, making them prone to developing serious infections
- normal 50 kg foal = L of good quality IV plasma
- sick foal = several transfusions of plasma
(recheck IgG concentration within 12 hours of tx)
What is the most common cause of meconium impaction? What is the most common sign?
young foal (1-2 days) has not ingested enough milk, causing a painful impaction, which increases sympathetic tone and decreases GI motility, making the impaction worse —> prolonged distension can cause a collapse of the vessels of the GIT walls
frequently erected tail with unproductive straining
What are the 2 main treatment options for meconium impaction? How are they performed?
- fleet enema - only once due to large amount of K
- warm water enema with small amounts of dish soap (can be irritating!)
- deliver 100 mL of warm water by gravity
- deliver 100 mL of mineral oil through a syringe and tube (don’t force against back pressure!)
- deliver 100 mL of warm water by gravity
What is another way of delivering enemas to foals with meconium impactions?
ORAL
- mineral oil - 100-200 mL via NG tube, check for reflux first!
- acetylcysteine - breaks down dried mucus, can be irritating
- rehydration + IV fluids
When is surgery indicated for foals with meconium impactions?
severe distension, pain, or bloat = surgical decompression
What causes perinatal asphyxia syndrome (dummy foal)? What are the 2 most common timings?
hypoxic event near the end of gestation or during parturition causes the foal to be normal upon birth, but quickly becomes obtunded due to neurologic injury caused by reperfusion when oxygenation is reestablished
- prior to parturition - placental insufficiency, placentitis
- parturition - delay in foal’s delivery (stage 2) after loss of placental attachment
What comorbidity is commonly found in dummy foals? How are dummy foals treated?
septicemia
- feeding tube (don’t swallow well)
- prophylactic antibiotics
- anti-inflammatories - Flunixin meglumine
- supportive care and referral
- Madigan squeeze - simulate the physical pressure of the birth canal and “activate the switch” to an alert state
What is septicemia?
systemic disease associated with bacteria in the bloodstream
What is the most common pre-parturient source of infection in foals?
placentitis
- U/S shows thickened uterine walls
When should the placenta pass following the foal?
2 hours
What are the 4 parts of the placenta?
- umbilicus
- chorioallantois
- amnion
- hippomanes
What is the chorioallantois? What are the 2 surfaces?
membranous sac in which the foal develops
- ALLANTOIC = foal side, glistening white with visible vessels
- CHORIONIC = uterus side, red velvet-like surface where nutrient and gas exchange occurs
How should the chorioallantois appear upon placental delivery?
turns inside out - allantoic (white) outside and chorionic (red) inside
Where does the foal pass through in the placenta?
avillous area - cervical star
What is examined in an abnormal placenta?
- cervical star - if large, it can suggest an ascending infection or scaring with avascularization
- placental folds
- possibility of twins
- avascular areas - sepsis, pre-natal hypoxia
What are the 3 most common clinical signs indicative of pre-parturient placentitis?
- mare drips before foaling
- foal is sick at birth
- expelled placenta is edematous and heavy - should only be 11% of foal BW
What is the most common cause of heavy and edematous placenta upon delivery?
ascending infection —> check cervical star
- Nocardia commonly found in the cranioventral uterine body at the horn attachment
What is Red Bag? Amnionitis?
chorionic surface is on the outside, suggesting early detachment of the placenta before it is turned inside out by foal delivery
thickened amniotic sac associated with placentitis
How is pre-parturient placentitis diagnosed?
placental histopathology (including the cervical star) and culture
What is the normal gestation period of a foal? What is a premature, dysmature, and post-mature foal?
310-370 days
- PREMATURE = shortened gestation period resulting in a small foal with incomplete ossification of cuboidal bones (stifle, hock), lax tendons, poor thermoregulation, poor glucose regulation, low lung compliance, and high chest wall compliance
- DYSMATURE = normal gestation period, but foal is small
- POST-MATURE = prolonged hestation, normal size and development, but thin (fescue hay fungus)
What are the most common signs of prematurity in foals?
- round, domes head and drooping ears due to incomplete maturation of cartilage
- incomplete ossification of cuboidal joints - stifle and hock are developed last
- laxity - can cause dragging of heels on the ground
What are the most common sources of post-parturient sources infections?
- umbilical/environment
- ingested
- inhales due to weak suckle
Why are post-parturient infections so dangerous?
DISSEMINATION - bacteria enters the blood, multiplies, and travels to capillary beds in the joints, lungs, and other organs
- also associated with failure of passive trasfer - check IgG!
What are the 5 most common places of localized infections in septic foals?
- lungs
- joints
- CNS (meningitis)
- gut
- umbilicus
