Bovine Flashcards
What is the purpose of the intercornual ligament of the uterus? and which is the most clinically useful
retraction of the uterus from over the pelvic rim. ventral
What anatomic structure is important to be cognizant of when trying to place a urinary catheter or performing AI?
suburethral diverticulum
How many annular rings are there in the cervix?
4-5
true/false: there is an internal and external bifurcation of the uterus
true
When would you define puberty?
first behavioral estrus with ovulation
What are the age of puberty onset of the common breeds (female)?
dairy: 10-12mo
beef:11-15mo
What type of estrus cycle does the cow demonstrate?
non seasonal polyestrus
What is the average estrous cycle length?
21 days
What are the behaviors demonstrated by a cow in proestrus
increase activity, mounting
thin mucus discharge
WILL NOT STAND
How long does estrus last in a cow?
<18hrs
What is the defining behavior of a cow in estrus
standing to be mounted
When does ovulation typically occur?
24-30hr after LH surge OR 10-15 hours after end of estrus
What does “bleeding off” indicate?
a cow was recently in heat
What are the three ways to know when a cow was in heat?
- observed standing
- classic estral mucous discharged observed
- mestral bleeding off observed
What event marks the end of diestrus and when does it occur
luteolysis at about day 17
When must maternal recognition occur for it to be a viable pregnancy?
before luteolysis at day 17 of cycle
When is a bovine CL responsive to exogenous prostaglandin?
day 6-17
True/False: a cow is responsive to exogenous prostaglandin as early as day 4 in her cycle?
false, day 6
Where does fertalization occur?
ampulla
When does a zygote reach the uterus?
3-4 days after fertilization
What cause maternal recognition of pregnancy?
interferon tau
When does attachment occur?
day 21
when does placentome formation begin?
days 30-36
When are placentomes palpable?
75-90days
True/False: CL produces progesterone throughout gestation
true
when does the placenta begin producing progesterone
day 150
What is the average gestation length
280days
What are 5 signs of impending calving?
relaxation of pelvic ligaments
elevation of tail head
vulvar enlargement
undder enlargement and edema
loss of mucus plug
What do P4, E2, and relaxin levels do as the cow approaches parturition
P4 decreases
E2 increases
relaxin increases
How long does stage 1 last in cows vs heifers
heifers: 24 hours
cows: 2-6 hours
True/False: it is abnormal for stage 1 of parturition in a heifer to last longer than 15 hours
false, can go up to 24
How long is stage 2 in cows?
30min-2/4 hours
presence of a hippomane at birth is considered abnormal and is reason for concern
false, it is just an accumulation of proteins/minerals/etc that have precipitated
When is a placenta considered retained in a cow?
after 12 hours
an owner calls you and is concerned that her cow that has just calved has retained membranes. it has been 10 hours and she doesnt see it anywhere. should you be concerned? why or why not
no. 1 because its not retained until 12 hours and 2. the placenta should be hanging from the vulva, if it is literally nowhere to be found there is a possibility the cow ate it
When does postpartum ovulation occur in dairy cattle?
20-35 days postpartum. usually silent
When does postpartum ovulation occur in beef cattle? why is it different than dairy?
at about day 60, this is because beef calves are raised at their mothers side so feeding/suckling inhibits the release of GnRH
___ plays a key role in postpartum ovarian function
energy balance
When should a cows uterus be back to normal size postpartum?
19 days
An owner calls you to say that her postpartum cow (9 days) is having extremely bloody and foul smelling discharge. Should you be concerned?
Yes, if it was not foul smelling there would be no reason for concern, bt because it is foul smelling, need to go and check it out
True/False: scrotal circumference measurement is correlated with sperm producing ability
true
What defines puberty in male bovine?
the age when a bull can intromt and produce ejaculate with 50 million sperm with at least 10% progressive mobility
When does puberty occur in male bovine?
9-10 months
What is the normal volume of bull ejaculate
5-8mls
how many days does it take for sperm to go from nothing to being able to fertilize?
60 days
What is the purpose of a bull resting his head on a cows lower back?
courtship, testing for receptivity
When do you start breeding a heifer? with what goal in mind
14-15 months to have her calve at 22-24 months
Why is estrus detection such a problem? (5)
short estrus periods
some cows only have a few mounts
each mount lasts <10sec
human observation is boring and not done regularly
cows are night riders
What is the optimal time for AI?
midestrus to 6hrs post standing estrus
If you observe your cow in estrus around 7pm would it be ok to wait to breed her until the morning?
yes!
What is the purpose of semen extenders?
it is what allows semen to be frozen and thawed
What are three methods of pregnancy diagnosis
- 3wks post breeding: watch for return to estrus
- 28+ days: transrectal ultrasound
- 30-35 days: transrectal palpation
what is the size of a follicle at ovulation
~30mm
