Reproduction Flashcards
How long is gestation in dogs and cats ? (After LH surge)
Dogs: 63d
Cats: 65d
How long is gestation in dogs and cats ? (After LH surge)
Dogs: 63d
Cats: 65d
Why is there variability in time of gestation after breeding?
Delay in maturation of the oocyte after ovulation
Delay of fertilization by spermatozoa
Variable interval of mating to LH surge
What are expected bloodwork changes in queen/bitches?
Anemia (Increased total body water), increased APP, leukocytosis without left shift
What causes the luteolysis?
Fetal stress leads to fetal glucocorticoid secretion which leads to maternal prostaglandin secretion. Prostaglandin causes luteolysis (and decrease production of progesterone, which maintains pregnancy)
Describe the stages of parturition
Stage 1: Inapparent uterine contraction and progressive dilation of the cervix. Last 6-12hr in the queen, nesting behaviors/restlesness
Stage 2: Active uterine contraction and fetus expulsion. Bitch: First fetus born within 4hrs of start of stage II, and subsequent puppies within 15min to 2hrs. Queen: First fetus born within 1hr of start of stage II and kittens every 10-60 mins (But variable)
Stage 3: Fetal membrane expelled
Describe the medications used in medical management of dystocia
Oxytocin: Alter transmembrane ion current, increase Na permeability to uterine myofibril, mobilizes intracellular calcium stores and causes influx of extracellular calcium
Calcium gluconate: Increases stength of uterine contraction by its action on muscle contractility (calcium induced calcium release, calcium binding to troponin C)
Dextrose: hypoglycemia is unfrequent but can cause secondary uterine inertia
Describe a protocol for medical management of dystocia
1) Vaginal examination and radiographs to rule out fetal-maternal malproportion and obstruction
2) Assess electrolytes and blood sugar
3) Oxytocin 0.1U/kg IV (or IM)
4) If no fetus in 30 minutes, reassess fetal viability, administer calcium gluconate 10% (0.5ml/kg IV over 20 minutes) and an additional dose of oxytocin
5) If no puppies after 30 minutes, consider surgical intervention (or continue oxytocin q30 minutes)
What are the causes of dystocia. Cite which one are more common.
Maternal causes (75%):
Uterine inertia (Most common)- Primary complete (>71d post breeding, no evidence of stage II; overstretch or understretch from small/big litter, obesity, hypocalcemia, uterine infection/trauma, stress), primary partial (Evidence of stage II, but not efficacious), and secondary (Uterine fatigue)
Physical (Pelvic fracture, small pelvis, stricture/stenosis, uterine torsion, unicornal pyometra)
Malnutrition
Parasitism
Fetal cause (25%): Fetal malposition (most common), fetal death, fetal malformation/monster, oversized fetus
Veterinary assistance persued when?
- Labor not beginning after temperature decrease or calculated due date
- Stage II labor > 4 hours without fetal delivery
- More than 2 hours between fetus expulsion
- More than 30 minutes of unproductive contraction
- Substantial amount of green/black discharge prior to first fetus delivery
- Prominent bloody discharge at any time during labor
Medical management of dystocia indicated when?
No maternal or fetal distress
No birth canal obstruction
Labor has not been protracted
Fetal size consistent with likelihood of delivery
Describe an anesthesia plan for a C-section
1) Preoxygenation and surgical prep prior to induction.
2) Fentanyl bolus (Short acting) followed by propofol (short acting) for induction
3) Intubation and isoflurane at lowest dose possible
What are potential complications of oxytocin?
Uterine rupture, vasodilation/hypotension, placental separation and constriction of the umbilical vessels
What is the fetal mortality rate?
10-25%
What factors can increase fetal mortality rate?
Prolonged stage II (>5hrs) or fetal distress without intervention (>2-3 hrs with HR <160)
