Exam 2: Canine Estrous Cycle Flashcards
The cervix is located _______ due to its long length
intra-abdominal
Ovary of the bitch is surrounded by significant amounts of
________
adipose tissue
Make sure to go over this structure
during transcervical insemination (TSI),
otherwise semen will be left behind
Dorsal-Median Vaginal Fold
The _________ bridge assesses if the bitch is in heat
cutaneous
Puberty is _______ months in smaller breeds
but up to
_______ years in larger breeds
6-10 months- smaller breeds
2 years- larger breeds
Maximum reproductive capability is at
___ years old
3 years old
Puberty is defined by the ability of the
hypothalamic neurons to produce sufficient _______
GnRH
Bitches in puberty are less likely to exhibit _____
when ovulation occurs
estrus
What is a split or false heat?
Bitches in puberty exhibiting signs of proestrus (bleeding),
but estrus does not occur immediately afterwards
What is silent heat?
Ovulation that occurs in the absence of proestrus-estrus
behavior or signs
Dogs, Wolves, and Bears are monoestrus
typically having _________ estrous cycles per year
1 - 2 estrous cycles
Which stage of Estrous is described?
Initiation of overt activity
Proestrous
(Day -9 to Day 0)
Which stage of Estrous is described?
Time for breeding
Estrus
(Day 0 to Day 9)
Which stage of Estrous is described?
Pregnancy or pseudopregnancy
Diestrus
(Day 9 to 2 months)
Which stage of Estrous is described?
Period of quiescence and repair
Anestrus
(90 to 150 days after diestrus)
Time from beginning of one estrus to the beginning of the next
Inestrus period
What is the average duration of the inestrus period?
7 months
The absolute minimum cycle length (inestrus period)
is ________ months.
These 2 breeds are predisposed to short inestrus periods
4 months
Rottweiler, German Shepherd
What is the maximum cycle length (inestrus period)
and what breeds are predisposed to long inestrus periods?
12 months
African Basenjis
(If longer than 12 months, investigate for cause-hyperprolacteremia)
Vaginal _______________ epithelium
responds to estrogen
stratified squamous
Vaginal stratified squamous epithelium is
_______ layers thick in Anestrus
2 - 4
Vaginal stratified squamous epithelium is
________ cell layers thick by end of PROestrus
20 - 40 layers
Vaginal stratified squamous epithelial cells that are
fully cornified
are indicative of this stage
Estrus
Onset of diestrus is characterized by the sudden
appearance of __________ cells;
a change from mostly cornified cells,
to mostly noncornified cells
parabasal
What direction do you direct the swab when harvesting
cells for vaginal cytology?
Dorso-cranially
A bitch in ________ attracts males but is non-receptive
proestrus
Turgid swelling of the vulva and hemorrhagic vulvar discharge
via diapedesis of RBCs through uterine vessels
are physical changes seen in
_______
proestrus (coming into heat)
What hormone dominates in Proestrus?
Estrogen
(Low gonadotropins- FSH,LH)
(Low progesterone- <1 ng/mL)
Day _____ in canines is the day of the LH peak
Day 0
Peak ovulation is ___ days after day of LH peak (Day 0)
2 days after
Ovulation takes ______ hours to complete
24 hours
In the bitch, a ________ (2N) is ovulated (Prophase 1)
and must go through further meiotic division to a
secondary oocyte (1N) BEFORE oocyte is ready
for __________
In the bitch, a primary oocyte(2N) is ovulated (Prophase 1)
and must go through further meiotic division to a
secondary oocyte (1N) BEFORE oocyte is ready
for fertilization
How long is the secondary oocyte viable for fertilization?
3 - 4 days
Initial rise in P4 (Progesterone) corresponds to the
______ peak
LH
What is the modern standard for breeding management?
Progesterone (P4)
Progesterone level of ________ confirms ovulations
>15 ng/mL
Progesterone level of ________
means that ovulation is starting
5 ng/mL
(or a rise of 3 ng/mL in 24 hours)
For natural or shipped semen, breed at ___ and___ hours
after P4 (progesterone) gets to 5 ng
48 and 96h
For frozen semen, breed _____ hours
after P4 (progesterone) gets to 15 ng/mL or higher
72 hours
Embryos remain in oviduct for _______ days after ovulation
9 - 10 days
Canine oocytes are good for ____ hours post-ovulation,
A LONG TIME
108 hours
Breed _______ days after the LH peak
T/F:
LH assays are more definitive than progesterone assays
TRUE
Which assay requires daily blood samples to be taken?
LH assay
For a fertile breeding male dog,
want _____% normal morphology and _____% motility
of sperm
80%, 80%
Breeding males should test negative for this
Brucella canis
The normal size estimate of testes is determined
using this equation
Log Scrotal Width = 0.324 (logBW) + 1.249
Most commonly used method for semen collection in the dog
Manual stimulation and ejaculation
What are the 3 fractions of semen in a dog?
Pre-sperm
Sperm-rich
Prostatic portion
These drugs are used in conjunction with
manual stimulation to increase sperm numbers in ejaculate
Oxytocin
PGF2a
What is the breeding dose of spermatozoa
for the dog?
200 x 10^6
What stain is used to assess sperm individually?
Eosin Nigrosin stain
Which methods can be used to breed with
frozen semen?
Transcervical
Surgical (midline laparotomy)
T/F:
Vaginal strictures/bands are a heritable defect
FALSE!
Developmental defect
The term used for when
2 males breed the same female during a single estrus
resulting in a litter of pups with 2 sires
Superfecundation
