dairy 2

Question 1

tell me the relationship between fertility and milk production

Answer 1

increase milk yield = increase metabolic requirements = lower BCS = lower fertility

Question 2

how does nutrition play into transition cow reproduction?

Answer 2

high demand for E but animal not eating as much as she needs = NEB following parturition

this can delay uterine involution and difficult to get them cycling again. want them to be out of NEB ASAP

Question 3

what is the ideal BCS at parturition?

Answer 3

3

Question 4

cows that keep or gain BCS during transition and/or from calving = _____ repro activity and ______ likely to keep pregnancy

Answer 4

earlier, more

Question 5

low BCS = ______ of anovular cows

Answer 5

increase

Question 6

BCS of _____ = low fertility after OvSynch and FTAI

Answer 6

≤2.5

Question 7

high BCS (>3) after calving = ?

Answer 7

metabolic problems (ketosis)

Question 8

the objective of preg checks is to?

Answer 8

dx open cows = most important!

dx pregnant cows

Question 9

how can you dx pregnancy in cattle?

Answer 9

direct (clinical)
- palpation & US

indirect (lab)
- P4, PSBP (pregnancy-specific protein B)

Question 10

what do you send to the lab to dx pregnancy?

Answer 10

• P4 (2 samples = best results)
• PSPB

Question 11

when should you palpate to find out if cow is preg?

Answer 11

35-40 days post-breeding

Question 12

how can you tell if cow is preg by palpation?

Answer 12

fetus/embryonic vesicle
- 35-65d =embryonic vesicle
- 55d+ = fetus

secondary signs include:
- >100d fetus in cavity
- ≥ 30-90 d membrane slip
- >90+ placentomes
- >105d uterine artery flow (fremitus)

Question 13

when can you dx pregnancy on US?

Answer 13

• 30d (retraction)
• 50d complete tract retraction necessary

Question 14

when can you perform fetal sexing on US?

Answer 14

> 55 days
look for scrotum or vulva

Question 15

how can you determine fetal viability?

Answer 15

US
- heartbeat
- movement

Question 16

with twins, there is an increase risk of what?

Answer 16

• embryo and fetal loss
• abortion
• stillbirths
• dystocia
• neonatal calf mortality
• low BW
• freemartins

Question 17

true or false: twins are more likely to occur in dairy cattle than beef cattle

Answer 17

true
related to higher milk production

Question 18

what is the difference between embryo death and fetal death

Answer 18

embryo: <40days
fetal: >40 days (full attachment)

Question 19

embryonic losses occur often within ____ post-service

Answer 19

28-30days

Question 20

embryo mortality often occurs when?

Answer 20

• fertilization
• zygote quality
• synchronization for 1st cleavage
• and 8-cell stage

lots of death in the spherical to tubular stage

Question 21

what are some common reproductive parameters? which is historically most used?

Answer 21

• conception rate
• pregnancy rate
• calving interval - most used
• average days open
• heat detection rate

Question 22

what is the problem with using calving interval?

Answer 22

depends on historical data (>2 yrs)

Question 23

what is the calving interval?

Answer 23

the time from 1 calving event to the next calving event

Question 24

what is average open days (OD)?

Answer 24

interval from calving to conception

Question 25

what is conception risk?

Answer 25

number of cows pregnant/# cows bred

only cows AI’d

Question 26

what is pregnancy risk?

Answer 26

number of cows pregnant/# cows eligible to be bred

this is standard to evaluate dairy herd repro performance

probability of open cows to become pregnancy per unit time (21d) - how quickly we get cows pregnant!

Question 27

what does pregnancy risk take into account and what does it not take into account

Answer 27

takes into account heat detection rate and conception rate

doesn’t take into account days open

Question 28

what is heat detection rate?

Answer 28

number of cows bred/# eligible cows (in a 21 day period)

Question 29

what is the relationship between voluntary waiting period, avg days open, and milk production?

Answer 29

higher avg days open = more days low production or extra dry period