2 Reproductive Tract of the Bitch OvaryOviductUterine HornUterine BodyCervixUrethralOpeningVaginaConstrictorVestibuliClitorisFossaClitoridisVulva
3 Physiology of the Ovarian Cycle in the Bitch PubertyIn most bitches begins at 6 to 9 months of age.Ovarian Cycle in the bitch is monoestrous. Interval fromcycle to cycle varies among breeds and can be affected byenvironmental cues.Range: 4 to 13 MonthsAverage: 7 Months
4 Ovarian Cycle is Divided into Four Stages A. ProestrusB. EstrusPhysical 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 estrusVulva 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 ofcornified epithelial cells with little debris. Behavior - bitch seeks maleturns hindquarters towards him, raises pelvic region, waves tail to oneside and finally stands for mating by male.Wolf Heat - (split heat) Have apparently normal heat but go out of heatwithout ovulation. Followed by another heat 2-6 weeks later (Fertile Heat)
5 C. Metestrus D. Anestrus Pseudopregnancy Loss of vulva swelling and no discharge. Vaginal cytology is nocornified cells and high numbers of White Blood Cells. Behavior -non-acceptance of malePeriod of ovarian inactivity and no vaginal dischargeWill not return to heat again until at least 4 monthsExtension of metestrus period in which progesterone concentrationsremain elevated. Female will have nest building behavior and enlargedmammary glands.
6 Endocrinology of the Estrous Cycle in the Bitch Higher Brain CentersHypothalamusGnRHAnterior PituitaryFSHLHOvaryEstrogenProgesterone
7 Provides sexual posturing Changes During Estrus of BitchVulva Swollen and EnlargedBloody dischargefrom vulvaCopulationAggressivetowards MalePassiveProvides sexual posturingto male for copulationProestrus EstrusIndicates Day ofPeak in LH
8 Hormonal Patterns During Estrous Cycle of BitchFertile PeriodOvulationFertilizationEstrogenCompletionof Meiosis IArbitrary Plasma ConcentrationsProgesteroneLHDays from LH Peak
9 Ovulation:Fertilization:Ova are released from the follicles approximately two tothree days following initiation of LH surge.Ovulated ova are not ready for fertilization (must completeMeiosis I) and therefore are not fertilized until Day 4 to 7following the LH surge.
10 B. LH PeakC. Plasma ProgesteroneThe greatest number of ovulations occur 24 to 72 hoursafter the LH peak. Breeding can be timed from the LHPeak to the fertile period 4 to 7 days later.Plasma progesterone concentrations rise prior to ovulationin the bitch. This occurs because follicles will start luteinizationbefore ovulation. Measurement of serum progesteroneconcentration can be used as a means to determine day ofovulation and breeding but concentrations can be highly variableand the following are only guidelines.Baseline Progesterone = 1 ng/mlDay Preceding Ovulation = 3-4 ng/mlDay of Ovulation = 4-8 ng/ml
11 Hormone Concentrations During Pregnancy and Parturition MatingProlactinProgesteroneCorticosteroidsArbitrary Plasma ConcentrationsTotal EstrogensDays of Pregnancy
12 BreedingDog achieves intromission by vigorous thrusting of thehindquarters . The bulbus glandis swells (6X4 cm) in the vagina inwhich vulva sphincter muscles contract around the penis formingthe copulatory “tie”.First Stage of CoitusThe “Turn”Second Stage of Coitus
13 Signs of Impending Parturition 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 consistentsign of impending parturition. Presence of milk in mammarygland is not an accurate sign.Decrease in body temperature from 38 to 37oC just beforeparturition.
14 ParturitionFirst Stage of LaborAverages 4 hours but can last 6-12 hoursPeriod in which the cervix dilatesBitch will be uneasy, refuse food, pant, vomiting andfrequently looking at flank.Visible straining of bitch in the sitting position and back againstthe box. Placental membrane will break and there will be fluiddischarge from vulva. Amnion covering the pup will be visibleas it passes through the cervix, vagina and out the vulva.Membrane will rupture spontaneously or through licking of dam.After the start of labor (active contractions) first fetus cannot beexpected to survive more than 6 hours in the uterus. Fetusesshould be delivered within 2 hours of each other. Usuallyinterval between puppies is about 30 minutes.Second State of Labor
15 Third Stage of LaborPassage of fetal membranes should take 5 to 15 minutes.DystociaDefinition: Any problem with delaying normal birth of fetus.SymptomsAbnormal 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.