Test 1: 6 nonpregnant cow Flashcards
open cow
not pregnant
what is the voluntary waiting period
time producers wait before attempting to re-breed a cow
Young females that have not had a calf are called —
heifers
Good husbandry and veterinary services are essential to ensure most heifers reach puberty by —months of age
12 to 14
Most heifers will reach puberty when they reach — of their mature weight.
55-65%
in cow, The uterus is freely moveable when it is normal and the female is less than —
70 days pregnant
in cows, the placenta is attached to the uterus by
endometrium: caruncles
placenta: cotyledons
three parts of the oviduct
infundibulum
ampulla
isthmus
normal size of cow ovary
4 x 3 x 2 cm
Average CL size in cow is —
18-25 mm
CL’s with cavities < — are considered normal and should not be confused with luteal cysts (cavity —).
12 mm
> 20 mm
estrous cycle in a cow is
polyestrous
(non seasonal)
estrous length of cow
21 days
17-24 days
duration of estus in a cow
15 hrs
(8-18hr)
onset of estrus to ovulation in cow
30 hrs
cows ovulate after estrus
gestation length of cow
280 days
(279-287)
placental classification of cow
cotyledonary syndesmochorial
After puberty, a female cow continues to have regular estrous cycles approximately every —
21 days
(18-24 days)
stages of estrous in a cow
estrus (Day 0- 15 hrs)
metestrus (Days 1-3)
diestrus (Days 4-18)
proestrus (Days 19-21).
Each cycle consists of a long luteal phase when the cycle is under the influence of — and a shorter follicular phase where the cycle is under the influence of —.
progesterone
estrogen
— lasts approximately 3 days and correspond to Days 19-21 of the estrous cycle.
Proestrus
what happens to hormones during proestrus
- PGF2⍺ is produced and that causes CL regression which leads to a decrease in progesterone, this will lead to a decrease in inhibition of LH
- LH will start to increase
- follicles starts to increase in size → increased estrogen
proestrus- day 19-21
behavior of cows in proestrus
- increased activity
- ↓ eating and milk production
- licking perineum of other cows
- mounting other cows
- females do not stand when mounted
how long is estrus in cows
15 hrs
what happens to hormones during estrus in cows
- increasing estrogen- peak 12-18hr before estrus
- LH surge at beginning of estrus
- ovulation 30 hrs after LH surge
when is ovulation in a cow
30 hrs after LH surge
* estrus starts at the peak of the LH surge
* estrus lasts 15 hrs- ovulation 15 hrs after estrus
* Estrogen secretion peaks 12-18 before onset of estrus and results in the LH surge that triggers ovulation.
behavior of cow in estrus
females stand when mounted
* same signs as proestrus
* mounting other cows
* increased activity
* decreased feeding
poor — is the #1 cause of reported anestrous and poor reproductive performance in herds using AI
estrus detection
* onset of estrus coincides with the LH surge, estrus lasts 15 hrs, ovulation occurs 30 hrs after LH surge
how to detect a cow in estrus
- teaser bulls
- watch behavior: BID, for 30 mins
- have a good recording system
- Heat detection is most effective when the cattle are calm and not being fed or disturbed.
when to inseminate a cow
12-24 hrs after start of estrus
when is metestrus in cow
3 day
D1-3
this is when ovulation occurs
hormone levels during metestrus
Day 0-3
Ovulation occurs during early metestrus. The sudden decline in circulating estrogen observed just prior to ovulation releases negative feedback on the HPG axis and results in an FSH surge, which in turn stimulates the growth of the first follicular wave of the cycle. The corpus hemorrhagicum (CH), which is the ‘bloody body’ that formed from the follicle after ovulation, is developing into a corpus luteum and circulating progesterone concentration starts to increase during metestrus.
— occurs during early metestrus. The sudden decline in circulating — observed just prior to ovulation releases negative feedback on the HPG axis and results in an —, which in turn stimulates the growth of the — of the cycle. The corpus hemorrhagicum (CH), which is the ‘bloody body’ that formed from the follicle after ovulation, is developing into a corpus luteum and circulating — concentration starts to increase during metestrus.
Ovulation
estrogen
FSH surge
first follicular wave
progesterone
metestrus occurs — hrs after ovulation
15-36 hrs
true or false
if you see metestrus hemorrhage you should breed the cow
false
too late to breed
ovulation occured 15-36 hrs ago, oocyte only alive for 6-12 hrs
when is dietrus in cow
14 days (D4-18)
what happens to hormones during diestrus
- CL growth = ↑ progesterone
The CL reaches its maximum size and produces the most progesterone at mid-cycle (around Days 8-15). Under the influence of high progesterone, LH secretion is tonic and relatively low. Waves of follicles continue to emerge and regress as the result of interplay between FSH and estrogen. In the absence of an embryo, the endometrium starts producing prostaglandin F2-alpha at the end of diestrus.
