Feline Reproduction
Parturition
- Milk may be obsereved just prior to parturition - uncommon
- Prepartum rectal temperature drop - is not obsreved
- Posterior presentation is common, does not predispose to dystochia
Pregnancy
- Ovulation follows coitus by 24-30 h
- Fertilisation in oviduct
- as morulae pass into the uterine horn by day 4-5 postcoitus
- superfecundation
- Transuterine - intercornual migration
- Implantation - 12-13 (14-16) days after ovulation
- Endotheliochorial (4 layer) placenta zonaria
E2
- remains low during the first 35–40 days of pseudo-pregnancy similar secretion pattern, with higher values, is observed during pregnancy
- in the second half of gestation E2 concentrations start to vary, commencing with decreasing P4 concentrations, and increase toward parturition > Estrus behavior
Feline placenta is capable of producing both P4 and E2
Intraplacentally produced P4 has a supplemental role with mostly local effects
Relaxin becomes detectable at about day 20–25 of gestation
PRL is elevated during the last one third of pregnancy
During pseudo-pregnancy, PRL remains generally at basal levels
ICC in queens: DBP = (mm – 62.03)/1.1
BP in queens: DBP = (mm – 23.39)/0.47
- Short partial anorexia, vomiting
- First 3-4 weeks > minimal weight gain - Queens should be fed a normal prebreeding ration
- 4-6 weeks - Caloric intake should be increased gradually about 50%
- Final weeks -70%, maintain the optimal body condition
underweight - maintaining lactation
obesity - dystochia
- Begins - the queen allows to mount and breed
- Behavioral stage of receptivity to mating
- Occurs during peak follicular activity and E2 secretion
- Lordosis, tail deviation, head rubbing, vocalization
- Observed only a minority of queens
- Rubbing of the head and neck against of any convenient object
- Vocalizing and rolling on the ground
- Not permit breeding, nonreceptive - Attracts the toms but refuses
- Rising serum estradiol (granulosa cells of the ovarian follicles)
- Effect on vaginal epithelium >
- increased number of epithelial cell layers
- vaginal cornification > the proportion of anuclear superficial cells increases (10%)
- Vulvar labia are nonresponsive to E > remain small
- Not observed - vaginal bleeding
Peak vaginal cornification occurs at time of peak E2 concentration
Anuclear squames 10% >> 40% (by the 4. day)
Mating
5-50 sec - Mounting and grasping of the neck by male
0,3-8 min - Positioning
1-30 sec - Intromission, ejaculation, queen's coital cry
0-1 sec - Dismounting
1-7 min - Queen's after-reaction > disoriented rolling, stretching, genital licking
Puberty
- The puberal estrous occurs 6-9 months of age
- incfluenced by
- Time of year/photoperiod
- Body condition - at least 80% of adult body weight (2,3-3,2 kg)
- Oriental breeds (Siamese, Burmase) - very young age
- Longhaired and Manx - later onset of puberty (11-21 months)
- in queens that have not been induced to ovulate, Ø CL
- low E2, P4
- no sexual behavior or receptivity
Occasionally, queens appear to miss an interestrous
- estrous behavior persist during two or more follicular than interestrous phases
- cyclic E fluctuations -but the lowest E conc. remained above the 20 pg/ml
- During estrus
- Morphologic evidence of CL development
Reesthabilishment of ovarian activity can begin 7-10 days following luteolysis in both pregnant and pseudopregnant queens
Lactation and suckling of kittens may cause lactatioanal anestrus > 2-3 weeks after weaning
- Diestrus - time of functional corpora lutea
- P4 dominance
- Ovulation, Ø fertilization
- Luteal phase of nonpregnant queen is one-half the duration of the normal gestation period
- Spontaneous ovulation - without male contact
- Infertile copulation
- Artificial stimulation of the vagina by probing with cotton swab > induce ovulation
No clinical signs
40-45 days "rest period"
P4
is similar in pregnant and pseudo-pregnant cats until days 10–12 of g., when implantation takes place in pregnant
- increase dynamically, reaching peak values (~30–40 ng/ml) at day 21.
- thereafter, gradual decrease toward parturition
in pseudo-pregnancy
- similar initial P4 secretion - peak levels > lower than during pregnancy, followed by a gradual decline (dropping to <1 ng/ml) by days 36–46
- the luteal phase in pseudo-pregnant cats lasts about half of its length in pregnant queens
Luteal regression/luteolysis during pseudo-pregnancy appears to be a passive degenerative process in the absence of a luteolytic principle of uterine origin
Prepartum luteolytic mechanism > signifi cant increase in fecal and serum PGF2α
This placental signal is missing in pseudopregnant queens
Mariusz P. Kowalewski (2017)
meaning that they can go into heat several times during a season,
repeatedly exhibits estrus behavior in a given season
- Cycles repeatedly throughout a breeding season
- Northern hemisphere -January/February with gradual frequency decline until September/October
- Anestrus from November until end of January
- Hot summer, stress - interrupts
- Hours of daylight - major impact on the onset and the duration of ovarian activity
Long-day breeders, are sexually active in spring and summer.
Prolonged anestrus results from decreasing or short day length (< 8h/day)
When the photoperiod is shortened, melatonin and PRL secretion are enhanced > reducing ovarian function
12h/day+
interrupted darkness
~16 day
12h/day +
social stimuli
~21 day
Induced ovulator - by coitus
- Vaginal stimulation is transmitted via spinal afferent nervous pathway to HT> increased neural activity > GnRH release > LH peak
- LH correlated with the number of copulation, max LH - 4h after 8-12 copulations
- about 50 % of queens ovulating after a single copulation
- Most queens do ovulate following 4 (or more) copulation
- Ovulation occurs 24h after the LH peak
- number of matings does not influence the number of ovulated follicles
Spontaneous ovulation - with incidence ranging from 35% up to 87%
dr. Linda Müller
clinical veterinarian
Department and Clinic of Reproduction
University of Veterinary Medicine