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.