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8.1.1 The Estrus Cycle
8.1.1.1 Puberty
- Occurs between 4-12 months
- Silent Estrus
- Seasonal Periodicity
- Neuroendocrine control: Pineal Gland
8.1.1.2 Vaginal Cytology
- Estrogenic Stimulation
- Sampling Technique
8.1.1.3 Proestrus
- 1-2 days, lordosis, rolling and calling
8.1.1.4 Estrus
- Receptive to the tom cat
- Induction of ovulation by cervical stimulation
- LH peak depends on number of matings
- Induction with GnRH (25 mg single injection iM) will evoke LH peak
- Length may vary from 4-12 days, variation depends on successful coupulation
- Smear is 75%-100% superficial cells
- Post Partum estrus can occur as early as 10 days following parturition.
8.1.1.5 Diestrus and Pseudopregnancy
- Progesterone secretion last 40-45 days if induced to ovulate
- Mammary development may occur and nesting behaviour may develop
- Smear is parabasal cells with few intermediate cells and variable # of PMN’s
8.1.1.6 Metestrus
- 10-25 days in non-bred or stimulated female during January- October. Longer during months of October through December.
8.1.1.7 Anestrus
- Anestrus cat shows no sexual receptivity nor detectable serum levels of sex steroids
- Vaginal smear consists of small numbers of parabasal cell.
Comments:
8.2.1 Endocrinology
- Vaginal-cervical stimulation leads to neuroendoctrine reflex GnRH and LH release
- Ovulation follows coitus by 24 hours
- Cat sperm require 2-12 hours of in utero capacitation
- Unfertilized oocyte has a 24 hr lifespan.
- Fertilization occurs in the anterior 1/3 of the oviduct
- Ova enter the uterine horns 5-7 days later forming an endotheliochorial placentation in the zonary shape
- During the first 20 days of pregnancy a regenerative normocytic/ normochromic anemia is present. Average PCV is 26-30%
- Superfetation can occur with a difference in age of the population of kittens of as much as 10 days.
- Superfecundation, fetuses sited by different males is common.
8.2.2 Diagnosis
- Abdominal palpation between days 25-28
- Radiography at 38-45 days
- Ultrasound at 25 days
8.2.3 Nutrition
- Pregnant cat should be fed commercial cat food
- 25% increase in calories should be fed after the sixth week
8.2.4 Problems of Pregnancy
- Mummification occurs as a result of fetal loss but no absorption of fetal mass
- Spontaneous abortion can occur as a result of:
- Cycling during pregnancy
- Viral abortifacatants
- FVR, PL, FeLV, IFP
- Bacterial Infections
- Hypothyroidism
- Chromosome abnormalities
- Use of progesterone is considered dangerous because of masculinization of female fetuses and interference with parturition events
- Uterine Torsion: 90-360 degrees on long axis, relatively uncommon.
8.3.1 Pyometra
- Middle aged to older cats
- Induced by estrogen primed, progestational stimulation of endometrial tissue. Presence of vaginal bacteria, gram negative organisms, predispose the queen to the disorder.
- Open and closed pyometra may occur
- Treatment with PGF2 alpha (0.1 mg/kg body weight) every 12 hours until discharge stops. Antibiotic therapy, including vaginal douches is concurrent therapy.
8.3.2 Cyclic Failure
- Increased illumination and exposure to cycling females, wait one month
- Karyotype for intersex
- University of Minnesota Diagnostic Lab 612-373-5647 10 cc heparinized blood
- Thyroid Profile
- Michigan State University
- Diag Lab-Endocrine Section
- P.O. Box 30076
- Lansing, MI 48909
- Serum Progerstrone for checking the presence of retained CL’s
- Induction: GnRH 25 mg, once daily for three days breeding if receptive.
8.3.3 Breeding Failure
- Culture anterior vagina
- T3 T4 values
- Viral titers
- Surgical exploration: tubular tract aplasia
8.3.4 Estrus After Ovariohysterectomy
8.4.1 Mating Behaviors
8.4.1.1 Puberty
- First spermatiogensis at 4-6 months. Behaviors follow, spraying, mounting thrusts and neck biting.
- Unilateral and bilateral slow descended testicles may be moved into position with HCG therapy. (25-50 IU HCG, IM weekly for 4 weeks)
- Successful copulation and conception at 10 months
8.4.1.2 Copulation
- female is best bred on the males’ territory
- Attraction is the sound of crying and the pheromones in the anal and tail glands as well as the urine.
- Penile erection is followed by pelvic thrusts resulting in intromission. Ejaculation occurs quickly and penis is withdrawn. Female exhibits shriels and turns, seats and spits at the male. She will then role from side to side .
- Multiple breedings may occur the same day.
8.4.1.3 Reluctance to Mate
- Some males exhibit partner preferences and discrimination against females.
- Some females pull away at intromission so that ejaculation occurs outside of the vagina.
- Timid females should be acclimated to male’s territory for 2-3 days.
- Examine the penis for hair rings around the penis.
- HCG may be used in increase libido but should give maximum effect 1 week following administration.
8.4.2 Semen Collection and Artificial Insemination
8.4.2.1 Semen Collection
- Artificial vagina as been described for semen collection in trained males. An trained cat will mount the technician’s arm and have intromission with a rubber pipet bulb or small test tube.
- Electroejaculation can be accomplished under light surgical anesthesia (30 mg/kg ketamine). A teflon and stainless steel rectal probe is inserted and electrical stimuli of 2-10 Volts and 2-5mA will cause ejaculation. No adverse reactions occur.
- Post copulation vaginal washes may also be used to recover cat sperm.
- Epididymal tap under light anesthesia is also successful.
8.4.2.2 Semen Evaluation
- Volume 0.04 cc
- # sperm/ejac 50- 100M
- % Motility 80%
- % Abnormalities 5%*
- Ph 7.5
- 10M is suggested as the minimum number of sperm for conception.
- *Club tails, protoplasmic droplets
8.4.3 Reproductive Disorders
8.4.3.1 Testicular tumors
- Sertoli cell tumors primary feline testicular neoplasm. They are malignant and are only formed in older animals. No feminization signs are reported.
8.4.3.2 Intersexuality
- Karyotyping of male tortoise shell or calico cats shows a variety of abnormalities. Klinefelter’s Syndrome (XXY) is included in makeup of some cats.
- Black and Orange genes are sex-linked (X) chromosomes. Only one of 16 such cats was reported fertile.
- Pseudohermaphrodites have been reported. Usually male in gonadal sex and female in phenotype.
- Endocrine Levels
- Estradiol Estrus 60 pg/ml
- Anestrus 20 pg/ml
- Spayed 5-10 pg/ml
- Progesterone Day 21 Pregnant 24 ng/ml
- Day 60 35 ng/ml
- Prior to Queening 10 ng/ml
- Pseudopregnant 2-4 ng/ml
- Anestrus 1 ng/ml
8.5.1 Data Base
8.5.1.1 History
- a. General History
- b. Reproductive History
- 1. Onset of puberty Onset of Heats
- 2. Sign of Seasonal Behavior
- 3. Manner of Breeding
- 4. Previous Litters
8.5.1.2 Physical Exam
- a. General Exam
- b. Reproductive Exam
1. Testes and accessory glands
2. Ovaries, Uterus by ultrasound
3. Vagina by vaginoscope
8.5.1.3 Laboratory Aids
- a. Viruses
- 1. FIP, FELV, FVR, FP
- b. CBC, TBF
- c. Endocrine Disease screens
- 1. T3 T4
- 2. Plasma cortisol
- 3. Estrogen and Progesterone
- 4. LH/FSH
- d. Bacteriological Culture
- 1. Sheath
- 2. Vagina
- e. Mycoplasm Culture
- 1. Sheath
- 2. Vagina
