canine reproduction

Canine Reproduction

Reproductive Tract of The Bitch

Reproductive Tract of The Dog

Dog reproduction

• Estrus length 7-13 days• Ovulation type Spontaneous• Breeding 10-16 days from

start of estrus

• Gestation 60-66 days• Litter size 4-12 • Weaning 7-8 weeks

Reproduction

• Estrus every 6-8 months

• Estrus lasts 21-22 days

• Pseudopregnancy common

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

Canine Estrous CycleCanine Estrous Cycle

Ovarian Cycle is Divided into Four Stages

Physical turgid swelling of vulva and appearance of a bloody discharge.Vaginal cytology will change with very early non-cornified epithelialcells increasing towards end of proestrus. Behavior - bitch is restlessand secretes pheromones but is aggressively negative towards malebecoming 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 estruswhich is normal. Vaginal cytology will have a high concentration of cornified epithelial (anuclear/superficial) cells with little debris.Behavior - bitch seeks male turns hindquarters towards him, raises pelvic region, waves tail to oneside and finally stands for mating by male.

A. Pro-estrus

B. Estrus

Loss of vulva swelling and no discharge. Vaginal cytology is nocornified cells and high numbers of White Blood Cells. Behavior - non-acceptance of male

Period of ovarian inactivity and no vaginal dischargeWill not return to heat again until at least 4 months

Extension of metestrus period in which progesterone concentrationsremain elevated. Female will have nest building behavior and enlargedmammary glands.

C. Metestrus/Diestrus

D. Anestrus

Pseudopregnancy

Changes During Estrus of Bitch

-8 -4 0 +4 +8 +12

Proestrus Estrus

Aggressivetowards Male

Passive Provides sexual posturingto male for copulation

Bloody dischargefrom vulva Copulation

Vulva Swollen and Enlarged

Indicates Day of Peak in LH

Follicular Development

http://openlearn.open.ac.uk/file.php/1638/SK220_1_017i.jpg

Ovulation:Ovulation:

Ova are released from the follicles approximately two to three days Ova are released from the follicles approximately two to three days following initiation of LH surge.following initiation of LH surge.

Fertilization: Fertilization:

Ovulated ova are not ready for fertilization (must complete Meiosis I) Ovulated ova are not ready for fertilization (must complete Meiosis I) and therefore are not fertilized until Day 4 to 7 following the LH and therefore are not fertilized until Day 4 to 7 following the LH surgesurge.

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.

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

-10 -6 -4 -2 0 2 4 8 12 14

Hormonal Patterns During Estrous Cycleof Bitch

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Days from LH Peak

Estrogen

LH

Progesterone

Ovulation

Fertile Period

Completionof Meiosis I

Fertilization

Control of Estrus in the Bitch

A. AndrogensMibolerone

Mode of Action:

Administration:

B. Progestins

Ovaban

Mode of Action:

Administration:

(UpJohn) - Methytestosterone

Negative feedback on FSH and LH

Initiate 30 days prior to expected onset Proestrus

(Schering) - Megestrol Acetate

- Negative feedback on FSH and LH

Depends upon stage of estrous cycle.

Lower dosage needed if given 7 days prior to proestrus.A much larger dosage is needed to block ovulation if givenduring proestrus.

Induction of Estrus

GnRH Administration:

Estrus induction can be used to treat bitches that failto cycle or have silent heats. Response of fertile estrus ishighly variable.

Anestrus is the result of low FSH and LH. GnRH can beused to successfully induce estrus in the bitch. However,it requires frequent (every 90 min) administration over10 to 11 days. Specialized infusion pumps (mini-pumps)can be utilized to deliver the pulses of GnRH

GnRH analogs can be used to induce fertile estrus in thebitch without giving frequent injections.

Breeding

•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

Pregnancy Diagnosis

A. Abdominal Palpation

B. Radiography

C. Ultrasonography

Day 25-32

Day 42

Day 21

Radiography Diagnosis

Ultrasonography Diagnosis

Behavior of bitch is one of nest building, restlessness andseeking quiet, out of sight areas. Vulva becomes swollen, edematous and may have some vaginal discharge.Relaxation of pelvic and abdominal muscles is a consistent sign of impending parturition. Presence of milk in mammary gland is not an accurate sign. Decrease in body temperature from 38 to 37oC just beforeparturition.

Signs of Impending Parturition

ParturitionFirst 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.

Second State 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.

•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.

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 postureStrong and persistent labor for 20 minutes withoutdelivery of fetus.Weak and infrequent contractions for 2 to 3 hoursMore 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.

Contraception in Bitch

Surgical:

Physical: Intravaginal DeviceSilastic and polyethylene tubing placedin vestibule and vagine. 50% of bitchescan still tie and get pregnant. Adding copper ring increases effectiveness

Hormonal: Progestogens : Medroxyprogesterone - MAP Megesterol Acetate – MGA

Androgens : Implants – Mibolerone

Immunological : Immunize against LH Anti-ZP3 - anti-zona vaccine

OvariectomyHysterectomyTubal Ligation

Contraception in Male

Surgical :

Chemical Agents :

Immunization :

Castration - Correct behavior such as wandering fighting, and urine markingVasectomy - Tie Vas Deferens

Chorhexidine - injected into epididymis

Immunize against LH