1. Reproduction In Dogs

4. Physiology of the Ovarian Cycle in the Female Dog
Puberty:
In most dogs begins at 6 to 9 months of age.
Ovarian Cycle:
Monoestrous
Interval from cycle to cycle varies among breeds and can be affected by environmental cues.
Range: 4 to 13 Months
Average: 7 Months

5. Ovulation:
Ovas are released from the follicles approximately two to three days following initiation of LH surge.
Fertilization:
Ovulated ova are not ready for fertilization and therefore are not fertilized until Day 4 to 7 following the LH surge.

6. Canine Estrous Cycle Stage Duration in days External signs Proestrus
4-14
(9 days)
Enlarged Vulva w/ bloody discharge, restlessness, no courtship w/ male
Estrus
4-21
(10 days)
Clear to pink vulva discharge, female turns hindquarters towards him, raises pelvic region, waves tail, male acceptance and courtship
Diestrus 60
Vulva shrinks, no discharge, non-acceptance of male, terminates with parturation
Anestrus
100 +
Inactive ovaries, no vulva discharge, low steroids

9. Provides sexual posturing
Changes During Estrus Of Dog
Vulva Swollen and Enlarged
Bloody discharge
from vulva
Copulation
Aggressive
towards Male
Passive
Provides sexual posturing
to male for copulation
Proestrus Estrus
Indicates Day of
Peak in LH

11. Breeding First Stage of Coitus The “Turn” Second Stage of Coitus
Intromission by vigorous thrusting of the hindquarters.
Swelling of bulbus glandis swells (6X4 cm) in the vagina
Vulva sphincter muscles contract around the penis forming the copulatory “tie”.
First Stage of Coitus
The “Turn”
Second Stage of Coitus

12. B. LH Peak
The greatest number of ovulations occur 24 to 72 hours after the LH peak.
Breeding can be timed from the LH Peak to the fertile period 4 to 7 days later.
C. Plasma Progesterone (P4)
Plasma P4 concentrations rise prior to ovulation
- follicles will start luteinization before ovulation
Measurement of serum P4 can be used as a means to determine day of ovulation and breeding
- can be highly variable

13. Hormonal Patterns During Estrous Cycle
of Bitch
Fertile Period
Ovulation
Fertilization
Estrogen
Completion
of Meiosis I
Arbitrary Plasma Concentrations
Progesterone LH
Days from LH Peak

14. Hormone Concentrations During Pregnancy and Parturition
Mating
Prolactin
Progesterone
Corticosteroids
Arbitrary Plasma Concentrations
Total Estrogens
Days of Pregnancy

15. Signs of Impending Parturition
Nest building,
Restlessness and seeking quiet, out of sight areas.
Relaxation of pelvic and abdominal muscles is a consistent sign of impending parturition.
Decrease in body temperature from 38 to 37oC just before parturition.

16. Parturition First Stage of Labor Second Stage of Labor
Averages 4 hours but can last 6-12 hours
Period in which the cervix dilates
Bitch will be uneasy, refuse food, pant, vomiting and frequently looking at flank.
Second Stage of Labor
Visible straining of bitch in the sitting position
Placental membrane will break and there will be fluid discharge from vulva.
Membrane will rupture spontaneously or through licking of dam.
After the start of labor first fetus cannot be expected to survive more than 6 hours in the uterus.
Fetuses should be delivered within 2 hours of each other.
Usually interval between puppies is about 30 minutes.

17. Symptoms Third Stage of Labor
Passage of fetal membranes should take 5 to 15 minutes.
Dystocia
Definition: Any problem with delaying normal birth of fetus.
Symptoms
Abnormal fetal presentation, position or posture
Strong and persistent labor for 20 minutes without
delivery of fetus.
Weak and infrequent contractions for 2 to 3 hours
More than 4 hours from delivery of last fetus (if not last one)
Most common problem is uterine inertia (weak contractions),
size of fetus and birth canal.

19. Ovarian Cycle is Divided into Four Stages
A. Proestrus
B. Estrus
Physical turgid swelling of vulva and appearance of a bloody discharge.
Vaginal cytology will change with very early non-cornified epithelial
cells increasing towards end of proestrus. Behavior - bitch is restless
and secretes pheromones but is aggressively negative towards male
becoming more passive towards start of estrus
Vulva swelling will soften and discharge will be slightly pink to straw-
colored. Some females will still have a bloody discharge in estrus
which is normal. Vaginal cytology will have a high concentration of
cornified epithelial cells with little debris. Behavior - bitch seeks male
turns hindquarters towards him, raises pelvic region, waves tail to one
side and finally stands for mating by male.
Wolf Heat - (split heat) Have apparently normal heat but go out of heat
without ovulation. Followed by another heat 2-6 weeks later (Fertile Heat)

20. C. Metestrus D. Anestrus Pseudopregnancy
Loss of vulva swelling and no discharge. Vaginal cytology is no
cornified cells and high numbers of White Blood Cells. Behavior -
non-acceptance of male
Period of ovarian inactivity and no vaginal discharge
Will not return to heat again until at least 4 months
Extension of metestrus period in which progesterone concentrations
remain elevated. Female will have nest building behavior and enlarged
mammary glands.