Pregnancy diagnosis

Question 1

Why is not-returning to oestrus not always a sign of pregnancy?

Answer 1

missed observation e.g., presence of young suppressing oestrus
Pathological conditions e.g., persistent CL, cystic ovarian disease
Short oestrus-oestrus cycle?

Question 2

Describe the failure of pregnancy in the mare without pseudoprgnancyq

Answer 2

If pregnancy failure in days 1-5 - embryo lost whilst in uterine tube so returns to normal oestrus
If pregnancy failure in days 5-15 - no maternal recognition of pregnancy so returns to normal oestrus cycle (unless associated with uterine inflammation)

Question 3

Describe pseudopregnancy in the mare

Answer 3

Type 1:
- failure between days 15-36
- maternal recognition
- no return to oestrus
- primary CL will persist for ~40 days then regress
- CL can be lysed by PGF2a

type 2:
- failure between 36-140 days
- no return to oestrus
- accessory CLs persist for ~150 days
- CL cannot be lysed by PGF2a

Question 4

What are the common methods of detecting pregnancy?

Answer 4

Protein/endocrinological changes in urine/blood:
- no decline in progesterone at a defined time after mating
Detection of fetus or fetal membranes:
- ultrasound
- rectal palpation
- abdominal palpation
- radiograph
Physical changes in dam
Maternal changes

Question 5

Why are the false negative and positive in detecting sustained progesterone levels in pregnancy

Answer 5

False positives due to:
- high level of progesterone without pregnancy e.g., persistent CL
False negatives due to:
- confusing animals
- poor sample storage

Question 6

How are feto-placental oestrogens used to diagnose pregnancy?

Answer 6

feto-placental unit produces oestrogens
often found mid-pregnancy in plasma and urine
No false positives
Pregnancy specific oestrogens

Question 7

What specific hormones, other than progesterone and oestrogen can be used to detect pregnancy?

Answer 7

Relaxin:
- from CL and placenta
- used in bitch and queen
Placental lactogens e.g., PAG:
- produced by placenta in some species
- luteotrophic
- can hang around in blood => false positives

Question 8

What can be detected via rectal palpation in pregnancy?

Answer 8

Pregnancy specific enlargement of uterus (feels more doughy and fluid filled as it grows)
Fetal membranes e.g., membrane slip in cattle
Ballottement of the foetus

Question 9

What can be detected by abdominal palpation in pregnancy diagnosis?

Answer 9

detection of enlargement of the foetus
ballottement of the foetus

Question 10

What types of ultrasound can be used to detect pregnancy?

Answer 10

Simple doppler transabdominally - foetal HR is greater than maternal HR
B-more real time - transectal imaging, transabdominal imaging

Question 11

Describe the earliest stages of ultrasound detection of pregnancy

Answer 11

Detection of conceptus
- anechoic structure representing the yolk sac

Question 12

Why is it important to check thoroughly in the equine conceptus stage?

Answer 12

For detection of twins
‘popping’ - removes one foetus to give other chance to survive before they are fixed

Question 13

Describe the middle stages of detection of pregnancy using ultrasound

Answer 13

Detection of embryo and a heartbeat

Question 14

Describe the late stage identification of pregnancy by ultrasound

Answer 14

detection of foetal structures

Question 15

What physical changes are indicative of pregnancy?

Answer 15

Ausculation of foetal heartbeats
Uterine artery:
- enlargement
- change in blood flow => turbulent ‘buzzing’/fremitus

Question 16

Describe the external secondary changes used to diagnose pregnancy

Answer 16

Non-return to oestrus
Teat and mammary gland:
- reddening
- enlargement (not in bitch or cow after first calving)
- secretion of milk
- ‘waxing up’

Question 17

What are the internal secondary changes used to detect pregnancy?

Answer 17

Cervical mucous:
- period of elevated plasma progesterone
- becomes very dry and tacky
Vaginal wall thinning:
- oestrogen -> increases layers of vaginal wall
- prolonged progesterone -> few layers in vaginal epithelium

Question 18

What are the common methods of pregnancy diagnosis of the cow in order?

Answer 18

Failure to return to oestrus - 18-24
Transrectal ultrasound - 28
Transrectal palpation - 35
Transrectal detection of membrane slip - 35-90
Transrectal ballottement of foetus - 50
Transrectal palpation of caruncles - 80
Transrectal uterine artery fremitus - 105-210

Question 19

Describe the methods of pregnancy diagnosis in the ewe in orderq

Answer 19

Failure to be raddles - 16-19
Transabdominal ultrasound:
- detection of fluid filled uterine horn
- detection of caruncles
- day 30 onwards

Question 20

Describe the common method of pregnancy diagnosis in teh sow

Answer 20

transabdominal B-mode ultrasound from day 20:
- fluid filled horn
- later embry

Question 21

Describe the methods of pregnancy diagnosis in teh mare in order

Answer 21

Transrectal ultrasound - from d12
Transrectal palpation - d21
Plasma eCG - d60-120
Transrectal foetal ballottement - d80

Question 22

Describe the common methods of pregnancy diagnosis in the bitch in order

Answer 22

Transabdominal ultrasound - d21
Plasma relaxin - d25

Question 23

Describe the methods of pregnancy diagnosis in cats in order

Answer 23