Test 1: 6 nonpregnant cow

Question 1

open cow

Answer 1

not pregnant

Question 2

what is the voluntary waiting period

Answer 2

time producers wait before attempting to re-breed a cow

Question 3

Young females that have not had a calf are called —

Answer 3

heifers

Question 4

Good husbandry and veterinary services are essential to ensure most heifers reach puberty by —months of age

Answer 4

12 to 14

Question 5

Most heifers will reach puberty when they reach — of their mature weight.

Answer 5

55-65%

Question 6

in cow, The uterus is freely moveable when it is normal and the female is less than —

Answer 6

70 days pregnant

Question 7

in cows, the placenta is attached to the uterus by

Answer 7

endometrium: caruncles
placenta: cotyledons

Question 8

three parts of the oviduct

Answer 8

infundibulum
ampulla
isthmus

Question 9

normal size of cow ovary

Answer 9

4 x 3 x 2 cm

Question 10

Average CL size in cow is —

Answer 10

18-25 mm

Question 11

CL’s with cavities < — are considered normal and should not be confused with luteal cysts (cavity —).

Answer 11

12 mm
> 20 mm

Question 12

estrous cycle in a cow is

Answer 12

polyestrous
(non seasonal)

Question 13

estrous length of cow

Answer 13

21 days
17-24 days

Question 14

duration of estus in a cow

Answer 14

15 hrs
(8-18hr)

Question 15

onset of estrus to ovulation in cow

Answer 15

30 hrs
cows ovulate after estrus

Question 16

gestation length of cow

Answer 16

280 days
(279-287)

Question 17

placental classification of cow

Answer 17

cotyledonary syndesmochorial

Question 18

After puberty, a female cow continues to have regular estrous cycles approximately every —

Answer 18

21 days
(18-24 days)

Question 19

stages of estrous in a cow

Answer 19

estrus (Day 0- 15 hrs)
metestrus (Days 1-3)
diestrus (Days 4-18)
proestrus (Days 19-21).

Question 20

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 —.

Answer 20

progesterone
estrogen

Question 21

— lasts approximately 3 days and correspond to Days 19-21 of the estrous cycle.

Answer 21

Proestrus

Question 22

what happens to hormones during proestrus

Answer 22

• 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

Question 23

behavior of cows in proestrus

Answer 23

• increased activity
• ↓ eating and milk production
• licking perineum of other cows
• mounting other cows
• females do not stand when mounted

Question 24

how long is estrus in cows

Answer 24

15 hrs

Question 25

what happens to hormones during estrus in cows

Answer 25

• increasing estrogen- peak 12-18hr before estrus
• LH surge at beginning of estrus
• ovulation 30 hrs after LH surge

Question 26

when is ovulation in a cow

Answer 26

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.

Question 27

behavior of cow in estrus

Answer 27

females stand when mounted
* same signs as proestrus
* mounting other cows
* increased activity
* decreased feeding

Question 28

poor — is the #1 cause of reported anestrous and poor reproductive performance in herds using AI

Answer 28

estrus detection
* onset of estrus coincides with the LH surge, estrus lasts 15 hrs, ovulation occurs 30 hrs after LH surge

Question 29

how to detect a cow in estrus

Answer 29

• 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.

Question 30

when to inseminate a cow

Answer 30

12-24 hrs after start of estrus

Question 31

when is metestrus in cow

Answer 31

3 day
D1-3
this is when ovulation occurs

Question 32

hormone levels during metestrus

Answer 32

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.

Question 33

— 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.

Answer 33

Ovulation
estrogen
FSH surge
first follicular wave
progesterone

Question 34

metestrus occurs — hrs after ovulation

Answer 34

15-36 hrs

Question 35

true or false
if you see metestrus hemorrhage you should breed the cow

Answer 35

false
too late to breed
ovulation occured 15-36 hrs ago, oocyte only alive for 6-12 hrs

Question 36

when is dietrus in cow

Answer 36

14 days (D4-18)

Question 37

what happens to hormones during diestrus

Answer 37

• 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.