8. Feline Therio Flashcards
Feline estrous cycle general characteristics
-type
-timing
◦ Seasonal, polyestrous, induced ovulator
◦ Induced ovulators = require copulation to initiate the LH surge
◦ Estrus cycles occur at 4-30 day intervals in cats exposed to constant daylight (14 hrs)
◦ Prolonged anestrus > decreasing or short day lengths (autumn)
◦ Season begins Jan-Feb > peak is Feb-March
when feline pubertal estrus? what influences this?
◦ Pubertal estrous = between 4 – 12mnts of age
◦ Influenced by time of year & body condition
◦ Usually when reaches 80% of adult body weight
endocrinology underpinning the seasonality of the feline estrous cycle
> 14 hours of light (spring)
Hypothalamus releases lots of GnRH
pituitary gland releases gonadotropins
gonads release steroid hormones
steroid hormones act on hypothalamus causing release of even more GnRH
=> Positive feedback loop
<12 hours of sunlight (autumn)
pineal gland releases melatonin
>causes hypothalamus to release less GnRH
>pituitary gland releases less gonadotropins
>gonads release fewer steroid hormones
>less feedback to hypothalamus, releases less GnRH
=> Negative feedback loop
-melatonin decreases GnRH output
based on the mechism behind feline seasonal breeding, what could melatonin be used for?
could be used to stop intact queens from cycling!
feline estrous cycle phases
proestrus, estrus, interestrus interval, diestrus
is proestrus observable in most queens?
no, most enter estrus directly
how do males behave towards females during proestrus? how do females behave?
males are attracted but females non-responsive
◦ Continuous rubbing of head and neck
how long does feline proestrus last?
◦ Short lived - if it occurs at all (0.5-2 days)
hormone increased in feline proestrus
estrogen
characteristics of feline estrus:
behaviour
hormone profile
◦ Behavioral stage of receptivity to mating
◦ Occurs during peak follicular activity & estradiol concentrations
◦ Behavioral estrus
◦ Crouching in the front with hind end elevated = lordosis
◦ Threading with hind legs, deviation of the tail = vulva exposed for mating
◦ Vocalize, more head rubbing, affectionate behavior
how can we detect feline estrus?
◦ Estrus behavior
◦ Vulvar labia will only slightly increase in size compared to the bitch
◦ Mucoid discharge can be seen – won’t see bloody vaginal discharge
◦ Vaginal cytology > see cornification as in the bitch
> Not useful to tell you when to breed
feline mating behaviour? how long does mating last?
◦ Nose to nose
◦ Investigate perineal area – Flehmen
◦ Grab neck – very important
◦ Mount
◦ Threading – slides down the female
◦ Pelvic thrusting > intromission > ejaculation > 20 seconds
◦ Pulls away quickly > avoid being struck by female
◦ Queen licks vulva, rubs on the floor, vocalizes = “after reaction”
duration of feline estrus
Duration of estrus ◦ Variable
◦ Average: 5.8 days (Range: 2-19 days)
what causes LH surge in feline?
copulation causes the LH surge
>NOT ovulation
what does feline LH surge require for induction? what does magnitude depend on?
◦ Induced by copulation but requires hypothalamic/pituitary exposure to estrogen
> Needs to be in heat
◦ Magnitude of LH surge increases with number of copulations
how soon after LH surge/coitus will ovulation occur in the feline?
◦ Induction of ovulation occurs 29-40hrs after LH surge
>ovulation occurs 24-48hrs post coitus
when does diestrus occur in the queen?
◦ Follows estrus in the queen that has ovulated (induced or spontaneous ovulation)
what hormone rises in diestrus? when, relative to ovulation?
◦ Progesterone dominated > CLs
◦ Progesterone starts to rise from baseline within 24 hrs post-ovulation
how long does diestrus last in the queen?
◦ Lasts approx. 40 days in pseudopregnant queen
is pseudopregnancy visible in queens?
pseudopregnancy is often not visible externally in comparison to bitches
how does diestrus end in the queen? do they return to estrus?
◦ Ends with luteolysis (mechanism unknown in the cat)
◦ Return to estrus is variable
what is the feline interestrus interval?
hormonal and behavioural characteristics
length
◦ Period that follows one estrus and precedes the next in queens that have not been induced to ovulate
◦ Estradiol drops
◦ No sexual behavior or receptivity is present
◦ Length is variable
optimal breeding age for queen
◦ Between 1.5-7 years of age
why is blood typing important for breeding cats?
◦ Important for prevention of neonatal isoerythrolysis
purebred cats are more liekly to have what blood type?
B
should the female go to the male cat or vice versa for breeding? then, when should we breed?
Bring the female into the tom’s territory
◦ Ideally don’t breed day 1 of estrus
◦ Then starting on day 2, breed 3-4x daily until end of estrus, if possible (at least over 2 day period)
important hormone for feline pregnancy maintenance
progesterone, via CLs
length of feline gestation
◦ 63-66 days, on average, from rise in P4
◦ 56-69 days from mating
when does feline prolactin increase?
Unlike in dogs – our prolactin only increases if pregnant – during the last 3rd of pregnancy and during lactation
character of the feline placenta
◦ Endotheliochorial, zonary
◦ No obvious marginal hematomas
do feline follicular waves stop during pregnancy? Consequences of this?
Cats can continue to have follicular waves during pregnancy
◦ Can display estrus behavior during pregnancy
◦ Superfetation is possible
hormone changes upon queening? Temp changes?
Progesterone drops, but doesn’t necessarily have to
>the drop isn’t a prerequisite for onset of parturition
◦ Don’t see a temperature drop like in bitches
stages of feline parturition and signs
Stages very similar to dogs
Stage 1: cervical dilation/uterine contractions
◦ Restlessness is the most common sign
Stage 2: passage of fetuses
◦ Kitten should be delivered within 15 mins once noted at vulvar lips
◦ Can take a very long time (interruptions by 10-12 hours are possible)
Stage 3: passage of fetal membranes
stages of feline parturition and signs
Stages very similar to dogs
Stage 1: cervical dilation/uterine contractions
◦ Restlessness is the most common sign
Stage 2: passage of fetuses
◦ Kitten should be delivered within 15 mins once noted at vulvar lips
◦ Can take a very long time (interruptions by 10-12 hours are possible)
=> Should still ensure all is normal if there’s an interruption of more than 3-4hrs
Stage 3: passage of fetal membranes
is dystocia common for queens? causes? what cats are at increased risk?
no
causes similar to dogs
Purebred cats at increased risk
◦ Dolicocephalic and brachycephalic breeds > obstructive dystocia
main cause of dystocia in queens
uterine torsion
how do we treat dystocia in queens? when should we consider a c section? considerations?
Medical management
>oxytocin & calcium gluconate
◦ Cannot do manipulations: too small
◦ Same “rules” apply as in dogs (no obstructive dystocias, FHRs, etc.)
◦ “Quiet” place, left alone
No response to 2 oxytocin treatments = C section
◦ Pre-medicate queen at last minute
>kittens hard to resuscitate
if performing a feline c section when should we premedicate queens and why?
◦ Pre-medicate queen at last minute; kittens hard to resuscitate
when will queens return to cycling post partum? what is the character of these cycles?
Within 2 weeks post-partum, begin cycling again
Anovulatory cycles; at least @ start of lactation
>become ovulatory as lactation decreases
post partum conditions to be mindful of in queens
Very similar conditions to bitches
Retained fetal membranes > metritis
◦ Usually queen is good at cleaning–don’t see much in terms of discharge
◦ If note discharge >7 days post-partum, investigate
◦ Mastitis
◦ Hypocalcemia
Agalactia
◦ Sometimes can’t express milk – kittens are still gaining weight & healthy– not truly agalactia
◦ Uterine prolapse; more common in cats
◦ SIPS
◦ Poor mothering
Specific disorders common in cats
◦ Benign mammary hypertrophy/hyperplasia
◦ Mammary neoplasia
◦ Cystic endometrial hyperplasia (CEH)/pyometra complex
◦ Ovarian cysts
◦ Ovarian remnant syndrome
CASE:
7 month old female Sphinx
Was in heat 3 weeks ago
5 days after her heat, this started
Is doing well at home, eating/drinking, acting normal
What could this be?
Benign mammary hypertrophy/hyperplasia
hormone profile of Benign mammary hypertrophy/hyperplasia? when does it occur?
Progesterone dependent condition
◦ Occurs following ovulation (pregnant or not)
Common in young cats (13 weeks- 2 years)
clinical signs of benign mammary hypertrophy/hyperplasia in queens
See asymmetrical, firm, rapidly growing mammary tissue
◦ Can become bruised & ulcerated as they enlarge
Histologically, there is no evidence of inflammation other than at the level of the surface epithelium
diagnosis of benign mammary hypertrophy/hyperplasia
◦ Signalment
◦ Clinical signs
◦ Progesterone assay
◦ Biopsy in older cats to rule out neoplasia
treatment of benign mammary hypertrophy/hyperplasia
◦ Removal of progesterone source
◦ OHE, aglepristone, luteolysis or abortion(spontaneous)
how common is mammary neoplasia in cats relative to other types? what increases risk?
3rd most common tumor in cats
◦ Still overall rarely seen
Intact = 7x greater chance of developing mammary neoplasia
main concern regarding mammary neoplasia in cats
High rates of metastasis
◦ Malignant adenocarcinoma
> Occurs in 50-90% of cases
clinical signs of mammary neoplasia in cats:
◦ Older cats
◦ 1 or more masses (can have L and R mammary chain involvement)
◦ Are firm, can be well or poorly demarcated nodules (several mm to 10cm)
◦ Swollen nipples +/- exudate
◦ Ropy lymphatics
how do we diagnose mammary neoplasia in cats
◦ Tumor histology (FNA, biopsy)
how can we treat mammary neoplasia in cats? what is an important differential
◦ Surgery
◦ Chemotherapy
◦ Radiation
◦ Important to do metastasis check
Cystic endometrial hyperplasia/pyometra in cats is associated with what hormone?
high progesterone
Cystic endometrial hyperplasia/pyometra signs
Often see infertility signs prior to pyometra
◦ Due to endometrial changes noted (cystic hyperplasia)
Clinical signs of pyometra:
◦ Not cycling
◦ Depression, lethargy
◦ PU/PD
◦ Distended abdomen, vomiting
◦ +/- vaginal discharge
are ovarian cysts common in cats?
yes
signs of ovarian cysts in cats
If cyst cells are secreting estrogen:
◦ Persistent estrus
Or can have no clinical signs (no estrogen secretion)
True persistent estrus – like those caused by ovarian cysts – can be hard to distinguish from a normal cat (overlapping follicular growth)
how to diagnose ovarian cysts in cats?
◦ Ultrasound
how to treat ovarian cysts in cats?
◦ Luteinization with hCG (induce ovulation)
◦ Surgical drainage
◦ OHE
how to treat ovarian cysts in cats?
◦ Luteinization with hCG (induce ovulation)
◦ Surgical drainage
◦ OHE
Causes of EED/abortion in cats:
- FIP
- Feline Herpes Virus
- FeLV
- Panleukopenia
- Toxoplasma
- Salmonella
- Chlamydophila
- Mycoplasma
4 categories of infertility in queens
◦ Persistent anestrus
◦ Persistent estrus
◦ Cycling queens that refuse copulation with the male
◦ Cycling queens that fail to conceive after copulation with a fertile male
> 1st step is to determine if they ovulated
in a case of queen infertility, where should we look first for solutions?
look at management 1st
◦ Including breeding behavior
◦ Season? Photoperiod?
◦ Recent change in environment
◦ Partner discrimination
◦ Husbandry – vaccine status, deworming, etc.
What is the most common cause of infertility/subfertility in the bitch?
Poor bitch breeding management/ovulation timing
Pyometra most commonly occurs when? What hormone causes this disease?
progesterone; diestrus
What happens if a queen does not ovulate? What stage of the estrous cycle does she go into?
She goes into the interestrous interval
The induction of estrus is most effective when:
a) < 120 days have passed since the last proestrus
b) GnRH agonists are used
c) >120 days have passed since the last proestrus
c) >120 days have passed since the last proestrus
Select the most correct answer:
a) Ovulation is induced by copulation in cats
b) The LH surge is induced by copulation in cats
c) Cats can be induced to ovulate at any time during their estrous cycle
b) The LH surge is induced by copulation in cats
Benign Mammary Hyperplasia/Hypertrophy is most common in what type of signalment? What is an important part of the history that could lead you to believe that a cat was affected by Benign Mammary Hyperplasia/Hypertrophy?
Young Cats
Was recently in heat
