Doctors on Duty
Monday - Saturday

Hospital Hours:

Meadow Brook -
M-F: 7am - 5:30 pm
Sat: 8 am -1:00 pm
Sun: 10 am - 2 pm

Preston Road -
M-F: 7 am - 7:00 pm
Sat: 8 am - 5:00 pm
Sun: 10 am - 2 pm

Fact Sheet

Canine & Feline Pregnancy & Birthing Information

Pregnancy

Pregnancy Length - Dogs:

• Highly variable
• 58-68 days from last breeding.
• 57 days from first day of diestrus.
• 64-66 days from the Luetenizing hormone peak blood levels

Pregnancy Length - Cats:

• Less variable.
• 64-69 days from fertile mating.

Implantation

• Dogs – 13-15 days after ovulation.
• Cats – 11-14 days after ovulation.

Pregnancy Diagnosis Techniques

1. Palpation of the Abdomen

• Best done at 20-30 days because distinct round masses are more easily palpated.
• Pregnancy diagnosis after >30 days is difficult because the uterus becomes diffusely enlarged.
• Pregnancy diagnosis is possible again after about day 50 because individuals can again be palpated.
• Pregnancy detection by palpation is an art; difficult to do. Limited by the temperament of the female, obesity, abdominal tenseness, size of the female, small litter size, etc.

2. Radiography (X-ray)

• Useful in diagnosis of pregnancy, predicting dystocia, and giving a rough idea of littler size.
• By day 21-42 fluid filled uterine horns may be detected.
• After day 42 various degrees of fetal ossification (bone formation) may be detected.

3. Ultrasound

• By day 16-20 fetal vesicles can be visualized within uterine horns.
• After day 25 fetal heart beats can be detected.

4. Mammary engorgement

• An inconsistent indicator of pregnancy.
• Many females will not display mammary development till near term, especially primiparous females.

5. Behavior

• Many pregnant females will show decreased appetite – sometimes even total anorexia – for a few days during either the third or fourth week of pregnancy.
• This seems to be a fairly reliable, if non-specific, indicator of pregnancy.

6. Blood Tests

• Canine Serum Relaxin Test – may show positive as soon as day 16-33 after mating. Several manufacturers.
• The Witness Brand Relaxin test kit is intended to determine pregnancy in the bitch, as well as to distinguish between pseudopregancy and gestation.
• The kit measures relaxin hormone levels in plasma and serum samples.
• The presence of significant amounts of this hormone is a reliable indicator of pregancy.
• Relaxin can be detected in biological samples soon after implantation of the fertilized egg, which occurs 20-31 days post-LH surge, or approximately 16 to 33 days post-mating.
  
• Other information:
  o Early detection of planned or unplanned pregnancy.
  o Detection of pregnancy before or after abortion treatment.
  o Early detection of false pregnancy.
  o Diagnose fetal resorption or spontaneous abortion.
  o No refrigeration required.
  o Format: Rapid ImmunoMigration (Unidirectional Lateral Flow) - Stat
  o Kit size: 5 tests/kit
  o Price: varriable - $65.00 or more
  o Sample type: Plasma, Serum
  o Test time: Results available within 10 min.
  o Storage: Room Temperature (35-77°F, 2-25°C)
  
  

TABLE 2.
The techniques to determine pregnancy in the bitch and the range through which the procedure is accurate. The days listed are after the luteinizing hormone (LH) peak.

References.

1. A study guide to small animal reproduction. Barton & Herron. Texas A&M University