CS: Herd infertility

Question 1

How would you decided if a herd’s lameness prevalence /incidence was too high?

Answer 1

FIRST: look at farm records for the previous year
THEN: look at national levels

Question 2

How do you confirm that a herd/cows aren’t suffering from NEB? 2

Answer 2

Test for beta-hydroxybutyrate and NEFAs

Question 3

List some reasons for low milk yield

Answer 3

• 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

Question 4

What does a follicular cyst look like on ultrasound?

Answer 4

Size is highly variable
Fine wall (unlike luteal cysts)

Question 5

What does a luteal cyst look like on ultrasound?

Answer 5

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

Question 6

How do you differentiate a luteal cyst from a young CL?

Answer 6

Both are very similar on rectal palpation
Both have fibrinous tissue in lumen (cobweb appearance)
Easier to distinguish on ultrasound.

Question 7

List some oestrous detection aids

Answer 7

 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.

Question 8

When are the profit, breakeven and negative profit stages of lactation?

Answer 8

PROFIT: First 170 days of lactation
BREAKEVEN: day 170 - 250 of milking
NEGATIVE: day 250 onwards (av lactation time is 305 days)

Question 9

Is you have a longer calving interval, how does this affect profit?

Answer 9

more time on break even or negative profits period. No effect on length of profit period.

Question 10

What can delay the first post partum oestrous?

Answer 10

Parturition complications
uterine disease
COD
anoestrous
stress
NEB

Question 11

Why might the interval between first breeding and conception vary?

Answer 11

semen
timings of AI
technician ability
uterine disease

Question 12

What might lenghten the time to pregnancy establishment?

Answer 12

defective CL

Question 13

What might cause abortion in cows?

Answer 13

leptospirosis
BVDV
IBR
(Brucellosis, non-UK)

Question 14

What should be the first thing you determine on a rectal exam?

Answer 14

Whether animal is pregnant or not - you don’t want to manipulate the ovaries if she is pregnant!

Question 15

How do you determine if subclinical endometritis is present?

Answer 15

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

Question 16

How do you treat follicular cysts?

Answer 16

Synthetic GnRH (e.g. Receptal) and repeat after 7 days

Question 17

How do you treat a luteal cyst?

Answer 17

use a luteolytic dose of PGF2a

oestrous expected in 3-5 days

Question 18

Outline Oysynch

Answer 18

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.

Question 19

Outline the use of PRID or CIDR

Answer 19

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.

Question 20

What are causes of COD?

Answer 20

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

Question 21

When does COD most commonly occur?

Answer 21

within 3-8 weeks after parturition

Question 22

What is the herd incidence of COD?

Answer 22

5-25%

Question 23

What are the uterine changes with COD?

Answer 23

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

Question 24

How do you differentiate COD from a dominant follicle?

Answer 24

Rectal palpation is insufficient

Ultrasound v important to confirm this (and to differentiate luteal from follicular)