26 - Pregnancy diagnosis

Question 1

Why is early pregnancy diagnosis important

Answer 1

• minimize economic losses
• rebreed or cull non-pregnant animals

Question 2

Two pregnancy detection methods

Answer 2

1. Clinical detection: rectal examination, ultrasonography
2. Laboratory detection: detection of pregnancy associated substances, vaginal biopsy

Question 3

Absence of estrus as a pregnancy diagnosis method

Answer 3

• inexpensive, early indicator of pregnancy
• not always dependable due to silent heats, retained CL, early abortion

Question 4

Rectal examination as pregnancy detection method

Answer 4

• mainly used for large domestic species (cows and mares)
• somewhat invasive
• requires training/expertise

Question 5

Ultrasonography as a pregnancy detection method? Two types

Answer 5

• non-invasive
• requires special equipment
• requires training/expertise

1. Doppler method (sounds in presence of amniotic fluid)
2. real time ultrasound (images)

Question 6

Describe the doppler method of ultrasonography

Answer 6

• suitable for use in pigs, dogs, sheep and goats
• allows for the detection of a number of different indicators of pregnancy (sounds):
  1. increased blood flow in one or more uterine arteries
  2. fetal heartbeats*
  3. umbilical artery pulsations
  4. fetal movement

Question 7

Describe real-time ultrasonography

Answer 7

• propagation and interaction of sound waves through body tissues
• image based on intensity of the reflected echoes:
  No echo = dark
  Low-intensity echo = low density tissues (muscle) = gray
  High intensity echo = high density tissues (bones) = bright

Question 8

Describe real-time ultrasounds in pigs

Answer 8

• allows for non-invasive detection of pregnancy
• requires training/expertise and equipment

Question 9

Describe real time ultrasonography in cows and mares. What can you detect

Answer 9

• allows for non-invasive detection of pregnancy
• requires training/expertise and equipment

Confirmation of estrous cycle/pregnancy: ovarian structures, embryonic membranes, fetus(es), sex fetuses, follicles, CL

Question 10

Earliest detection after insemination with ultrasound in cattle, horse, pig, sheep, goat

Answer 10

Cattle = 25d
Horse = 18d
Pig = 21d
Sheep = 30d
Goat = 30d

Question 11

Describe pregnancy associated substances and hormones as pregnancy diagnosis

Answer 11

• Detected in serum or milk by assays or tests
• reliable
• inexpensive
• non-invasive
• requires purchase of on-farm assays or access to diagnostic services

Question 12

List pregnancy associated substances and hormones

Answer 12

1. P4 most common: commercial on-farm milk tests for cattle
2. estrone sulphate (produced by fetus): measure in plasma, milk, urine or feces
3. Equine chorionic gonadotrophin (eCG): in blood of pregnant mares

Question 13

Slide 17***

Answer 13

look

Question 14

Vaginal biopsy for pregnancy diagnosis

Answer 14

• in sows and ewes
• vaginal epithelium changes with pregnancy (number of cell layers is reduced)
• biopsy, fix, stain and examine tissue microscopically
• mainly for research, no practical application

Question 15

Look at slides/diagrams

Answer 15

Do it