Oestrus Cycle Flashcards
terminology
Follicle stimulating hormone - causes follicular development
luteinising hormone - causes ovulation and the development of the corpus luteum
Oestrogen - Involved in female reproductive behaviour
progesterone - maintains pregnancy
prolactin - causes milk development
oxytocin - causes uterine contraction and ‘milk let down’
Canine and feline uterus
Multiparous ( give birth to litters) species have uterine horns that facilitate multiple young
the oestrus cycle
reproductive tract and behavioural changes to ensure the production and fertilisation of female gamete (female cell-ova)
and the development of a conceptus (embryo)
oestrus phases
pro-oestrus - preparatory phase - FSH Oestrogen
Oestrus - period of ovultion and sexual receptivity - luteinizing hormone
Met-oestrus - preparation of the uterus for pregnancy,
maintains pregnancy
the end of this phase results in parturition - progesterone/prolactin
Anoestrus - reproductive dormancy - no hormonal involvement
canine oestrus
stage duration sign
proestrus - 4-14- interested in male dogs but wont mate
oestrus - 4-21- straw coloured discharge, courtship, male acceptance
Metoestrus - 60 - will no longer mate. mammary development. pregnancy occurs during this phase
Anoestrus - 100+ average 4 months - reproductive dormant
The canine breeding cycle
breeding cycle - Anoestrus
- pro- oestrus
-Oestrus
-Met- oestrus
The canine breeding cycle
canines are monoestrus - have 1 oestrus once per breeding season
- they may come into oestrus at any time of the year
-first season between 6 and 18 months old
- thereafter: every 6 months on average
exceptions 4 months/12 months
dogs have spontaneous ovulation - they don’t require external triggers
Feline breeding cycle
cats have induced ovuation
if ovulation doesn’t occur the corpus luteum isn’t formed and progesterone isn’t secreted
the corpus luteum is formed after ovulation. it secretes progesterone.
cats are polyoestrus - they cycle between oestrus phases
cats are seasonal polyoestrus, specifically long day breeders - they cycle only during feb to october
they hit puberty between 4-18 months
if born in the summer, will likely come into oestrus in spring
caring for the pregnant cat
65 days gestation
- vaccination pre-mating
- visible changes from day 21 onwards
- worming treatment toxocara catis - transmammary transmission, zoonotic risk
increase nutrition from early pregnancy until lactation
Gradual increase up to 50%
Consider smaller meal more often
Caring for the pregnant dog
63 days gestation
- abdominal palpation from 28 days
- vaccination pre - mating
- nutritional requirements do not change until last trimester
worming treatment for toxocara canis at day 42 due to transplacental and trans mammary transmission
dam should start to be made familiar with whelping box in last couple of weeks of pregnancy
exercise as normal / as much as dam wants but avoid strenous exercise
considerations for vet checks
prior to mating - vaginal cytology and progesterone assay (blood test) can be performed to estimate ovulation (canines)
During pregnancy
- conceptuses can be imaged with ultrasound from day 12
Abdominal palpation from day 15-20 (cats) and 28 days (dogs)
Relaxin (hormone released from the placenta) starts to increase from day 25
Day 45 clinical exam by MRCVS recommended. ideal juncture to answer any breeder questions, skeletal mineralisation has occured and relaxin levels peak.
Phantom pregnancy
all dogs have elevated progesterone during metoestrus and have physical changes similar to that during pregnancy
this normal phase is sometimes reffered to as convert pseudocyesis.
this normal phase is sometimes referred to as convert
clinical signs include mammary enlargement +/- behavioural changes is normal in both pregnant and non - pregnant dogs during this stage
Clinical pseudocyesis
when changes become exaggerated = exaggerated behavioural symptoms such as
Anorexia, nervousness, aggression, nest making, nursing inanimate objects, lactation and occasional false parturition
Treatment
pseudopregancy is associated with elevated progesterone which once declines (around 60 days) causes elevated prolactin levels
prolactin is luteotrophic if it is blocked this can reduce progesterone levels
treated with prolactin inhibitors such as bromocriptine or cabergoline - if we reduce prolactin, progesterone will also decline
oxytocin also known to be involved in canine maternal behaviour
pregnancy can lessen subsequent episodes
often neutered once lactation stopped
Nursing considerations
- promote client understanding and compliance
- encourage exercise, play and distractions
- remove any toys the dam is ‘ mothering’
- Encourage the use of an (elizabeth collar) or body suit if the patient is licking her mammary glands
