Connemara Jack Russell Terriers

(207) 221-0267

(207) 939-9404

Week One

• Fertilization occurs
• 2 cell embryos are in the oviduct
• The embryo is fairly resistant to external interference in development

Week Two (Days 8-14)

• Embryo will be 4 cell at start of week and 64 cell by end of week
• Embryo enters the uterus

Week Three (Days 15-21)

Week Four (Days 22-28)

• Development of eyes and spinal cords
• Faces take shape
• Fetuses grow from 5-10 mm to 14-15 mm
• Organogenesis begins - Embryos are at their most susceptible to defects
• Days 22-28 are the best days for a Sonogram to get a puppy count
• Days 26 - 32 are the best days to palpitate (i.e; feel for the puppies ...which is near impossible)

Week Five (Days 29-35)

• Development of toes, whisker buds, and claws
  
• Fetuses now look like dogs
• Gender can be determined
• Eyes (previously open) now close
• Fetuses grow from 18 mm - 30 mm
• Organogenesis ends -- embryos are now fairly resistant to interference with development

Week Six (Days 36-42)

• Development of skin pigment
• Fetuses should weigh around 6 grams and be 45 mm long
• Fetal heartbeats can now be heard with a stethoscope

Week Seven (Days 43-49)

• Growth and development continues

Week Eight (Days 50-57)

• Fetal movement can clearly be detected when Mother-to-be is at rest
• Puppies can usually be safely born from this point on

Week Nine (Days 58-65)

• Growth and Development continues

• Nesting behavior may be seen. By now she should have a place to go where she feels safe and away from other dogs, kids and noise. She should have a least 1 week (if not 2) where she has established her place to have her puppies. Appetite may disappear as whelping approaches. Not all, but most will stop eating altogether the day before.