CS: Herd infertility Flashcards
How would you decided if a herd’s lameness prevalence /incidence was too high?
FIRST: look at farm records for the previous year
THEN: look at national levels
How do you confirm that a herd/cows aren’t suffering from NEB? 2
Test for beta-hydroxybutyrate and NEFAs
List some reasons for low milk yield
- Mastitis – clinical and subclinical
- Systemic infection - metritis, endometritis
- Problems around calving – mastitis, metritis, ketosis, DA.
- Low BCS (some cows have BCS 1.5)
- Nutrition – poor quality, palatability or access
- TE deficiency
What does a follicular cyst look like on ultrasound?
Size is highly variable Fine wall (unlike luteal cysts)
What does a luteal cyst look like on ultrasound?
Thicker wall of luteal tissue around outer edge
Sometimes you see some white ‘cobwebs’ (of fibrous tissue) in the lumen of a luteal cyst as the cyst is trying to luteinise further –> cavity appears highly partitioned
How do you differentiate a luteal cyst from a young CL?
Both are very similar on rectal palpation
Both have fibrinous tissue in lumen (cobweb appearance)
Easier to distinguish on ultrasound.
List some oestrous detection aids
KaMaR , ‘Beacon’ or ‘Estrotect’ devices
Tail paint with or without teaser bull
Pedometers – increased movement when cow is in oestrous
CCTV
Head collar - also detect movement
Moomonitor- neck collar that measures physical activity, sends data to farm computer for analysis, text to mobile of farmer that it is ready for insemination. But remember if collar is heavy and concurrent lameness may create false positives and false negatives.
Choose a method but don’t rely solely on this.
Ferning pattern of cervical mucus indicates cow is in oestrous
Vaginal mucus electrical resistance probes (i.e. changes in vaginal impedence)
Vasectomise bull
Sequential milk P4 assays – at least 3 samples per cycle.
Make a point to observe cows at 9-10pm (time when most cows are bulling)
Abolish detection methods and use oesetrous-synchronisation with PGs or progesterone with single or double fixed time AI at 72 and 96 hours.
When are the profit, breakeven and negative profit stages of lactation?
PROFIT: First 170 days of lactation
BREAKEVEN: day 170 - 250 of milking
NEGATIVE: day 250 onwards (av lactation time is 305 days)
Is you have a longer calving interval, how does this affect profit?
more time on break even or negative profits period. No effect on length of profit period.
What can delay the first post partum oestrous?
Parturition complications uterine disease COD anoestrous stress NEB
Why might the interval between first breeding and conception vary?
semen
timings of AI
technician ability
uterine disease
What might lenghten the time to pregnancy establishment?
defective CL
What might cause abortion in cows?
leptospirosis
BVDV
IBR
(Brucellosis, non-UK)
What should be the first thing you determine on a rectal exam?
Whether animal is pregnant or not - you don’t want to manipulate the ovaries if she is pregnant!
How do you determine if subclinical endometritis is present?
Uterine cytology:
subclinical endometritis is defined as >18% neutrophils in uterine cytology samples collected 21-33 days post-partum or >10% neutrophils at 34-47 days post-partum
How do you treat follicular cysts?
Synthetic GnRH (e.g. Receptal) and repeat after 7 days
How do you treat a luteal cyst?
use a luteolytic dose of PGF2a
oestrous expected in 3-5 days
Outline Oysynch
give GnRH (day 0) to synchronise new wave emergence, PGF on day 7 –> luteolysis, GnRH on day 9 –> controls time of ovulation, AI on day 10.
Outline the use of PRID or CIDR
PRID for 8 days, PGF2α at day 7, then single insemination at 56hr after PRID removal or double fixed-time artificial insemination (TAI) at 48 and 72 hours after PRID removal.
What are causes of COD?
FAILURE OF PRE-OVULATORY STAGE TO: NEB decreased sensitivity of hypothalamus to E2 lower E2 concentration stress (lameness) uterine disease high milk yield genetics age lack of LR-R and FSH-Rs in developing follicles inappropriate release/lack of GnRH
When does COD most commonly occur?
within 3-8 weeks after parturition
What is the herd incidence of COD?
5-25%
What are the uterine changes with COD?
o 1st week of COD: wall is thickened and oedematous (because prolonged oestrous)
o End of 1st week: uterine wall becomes spongy.
o Chronic COD: atony and atrophy of the uterine wall.
o Markedly shortened uterine horns - occasionally
o Some mucoid-mucopurulent discharge present
o Hydrometra - seen occasionally
How do you differentiate COD from a dominant follicle?
Rectal palpation is insufficient
Ultrasound v important to confirm this (and to differentiate luteal from follicular)
