David noakes lecture Flashcards
What are the 4 broad categories of subfertility?
Structural
Functional
Management
Infectious
How often should a normal cow cycle
q18-24 days unless pregnant or within 4-6 weeks post partum
5 reasons for no observed oestrus?
freemartinism acylical/anestrus ovarian cysts silent heat not detected
What would you feel on rectal in an acyclical cow?
small flat ovaries, involuted tract
Causes of acyclicity
poor BCS, NEB, concurrent disease, high milk yield
How does low nutrition affect fertility?
Low IGF1 –> reduced response to oestradil & reduced production of GnRH, reduced response to GnRH & reduced FSH and LH, decreased ambryo growth & IFN tao production
What hormonal treatment could you give to an anestrus cow?
PRID or CIDR alone or with GnRH or eCG.
Need to correct nutrition etc as well
What does a normal follicle look like?
1.5-2cm diameter, thin walled, transient.
What does a vacuolated CL look like?
Same size as normal CL, fluid bit in it, identifiable ovulation point. Normal
What does a luteinised follicle look like?
<2.5cm, no sign of ovulation, large cavity. Occur early post partum
What does a follicular cyst look like?
thin walled (<3mm), >2.5cm diameter, fluid filled structure.
What does a luteal cyst look like?
thick walled (>3mm), fluid filled structure >2.5cm diameter. Produce P4.
What is the definition of a cyst?
> 2.5cm, lasts >10 days. Develop from anovulatory graafian follicle.
Which kind of cyst can result in nymphomania?
Follicular cyst (may secrete estrogen)
Why do cysts occur?
hypothalamic level: failure of LH surge (attenuated after calving). Hypothalamus less sensitive to oestradiol after calving.
Ovarian: reduced LH receptors in granulosa cells.
NEB –> NEFAs –> impaired follicular proliferation
How would you treat a follicular cyst?
GnRH/hCG then PGF
or PRID/CIDR for 10-12d
pyometra is associated with ____ _____ therefore treatment is ____
persistent CL
PGF2a
How often and for how long should cows be watched for estrus behaviour
20-30min
at least 3 times per day
best 9-10 at night
PGF method of fixed time AI?
2 lots of PGF2a 11 days apart then double AI at 72 & 96h or single at 84
How do you do the PRID method of timed AI?
PRID or CIDR for 7-9d with PGF2a 24h before removal & AI at 48 & 72h
What is involved in ovsynch?
day 0 - GnRH
day 7 - PGF
day 9 - GnRH
day 10 - AI
At what point does it become foetal death rather than embryonic?
42 days
General causes of embryonic death
Luteal deficiency/hormone imbalance embryopathic organisms oportunistic endometritis over/under nutrition stress genetic factors
How can you treat/avoid luteal deficiency?
PRID supplementation, hCG at 4-9 days post AI –> accessory CL
