dairy 2 Flashcards
tell me the relationship between fertility and milk production
increase milk yield = increase metabolic requirements = lower BCS = lower fertility
how does nutrition play into transition cow reproduction?
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
what is the ideal BCS at parturition?
3
cows that keep or gain BCS during transition and/or from calving = _____ repro activity and ______ likely to keep pregnancy
earlier, more
low BCS = ______ of anovular cows
increase
BCS of _____ = low fertility after OvSynch and FTAI
≤2.5
high BCS (>3) after calving = ?
metabolic problems (ketosis)
the objective of preg checks is to?
dx open cows = most important!
dx pregnant cows
how can you dx pregnancy in cattle?
direct (clinical)
- palpation & US
indirect (lab)
- P4, PSBP (pregnancy-specific protein B)
what do you send to the lab to dx pregnancy?
- P4 (2 samples = best results)
- PSPB
when should you palpate to find out if cow is preg?
35-40 days post-breeding
how can you tell if cow is preg by palpation?
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)
when can you dx pregnancy on US?
- 30d (retraction)
- 50d complete tract retraction necessary
when can you perform fetal sexing on US?
> 55 days
look for scrotum or vulva
how can you determine fetal viability?
US
- heartbeat
- movement
with twins, there is an increase risk of what?
- embryo and fetal loss
- abortion
- stillbirths
- dystocia
- neonatal calf mortality
- low BW
- freemartins
true or false: twins are more likely to occur in dairy cattle than beef cattle
true
related to higher milk production
what is the difference between embryo death and fetal death
embryo: <40days
fetal: >40 days (full attachment)
embryonic losses occur often within ____ post-service
28-30days
embryo mortality often occurs when?
- fertilization
- zygote quality
- synchronization for 1st cleavage
- and 8-cell stage
lots of death in the spherical to tubular stage
what are some common reproductive parameters? which is historically most used?
- conception rate
- pregnancy rate
- calving interval - most used
- average days open
- heat detection rate
what is the problem with using calving interval?
depends on historical data (>2 yrs)
what is the calving interval?
the time from 1 calving event to the next calving event
what is average open days (OD)?
interval from calving to conception
what is conception risk?
number of cows pregnant/# cows bred
only cows AI’d
what is pregnancy risk?
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!
what does pregnancy risk take into account and what does it not take into account
takes into account heat detection rate and conception rate
doesn’t take into account days open
what is heat detection rate?
number of cows bred/# eligible cows (in a 21 day period)
what is the relationship between voluntary waiting period, avg days open, and milk production?
higher avg days open = more days low production or extra dry period
