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
