Pregnancy diagnosis

Question 1

What is the general principle of non return to oestrus?

Answer 1

• Maintenance of the CL
• For polyoestrus animals if she doesn’t return to oestrus by 3 weeks after service she is assumed to be pregnant
• BUT in cows: pathological conditions e.g. luteal cysts, persistent CL might be the cause
• May also have lost the fetus very early on- this delays return to cyclicity

Question 2

Describe the species differences with pseudopregnancy:

1) Which one is it simply the non pregnant luteal phase?
2) Which one it is simply the non pregnant luteal phase WHEN it occurs?
3) which ones does it only occur in after pregnancy loss?

Answer 2

1) Bitch- simply non pregnant luteal phase
2) Induced ovulators- simply the non pregnant luteal phase when it occurs
3) Mare- occurs ONLY after pregnancy loss

Question 3

Describe pseudopregnancy in the mare

Answer 3

• Pregnancy failure
• If between 1-5 days the embryo is lost whilst in the oviduct so normal oestrus cycle continues as if she was never pregnant
• If between days 5-15 then there has been no MRP so normal oestrus occurs UNLESS, inflammation present–> this will cause a short cycle
• Pseudopregnancy type 1: failure between days 15- 36= MRP has occurred, will not return to oestrus, primary CL will persist for normal lifespan (40days) CL can be lysed by PGs
• Pseudopregnancy type 2: failure between days 36- 140= cups have formed, won’t return to oestrus, secondary CLs around for normal lifespan (150 days). CL CANNOT be lysed by PGs.

Question 4

What is Early conception factor?

Answer 4

-A glycoprotein produced in pregnant animals within 48hours of conception
-It is immunosuppressive
-

Question 5

How do you test for pregnancy diagnosis by early conception factor?

Answer 5

• Dipstick test for serum/ milk
• Used in cattle/ horses
• VERY LOW level of accuracy
• Pregnancy should be confirmed later by other means due to embryonic mortality

Question 6

What are the problems with using a lack of drop in progesterone to diagnose pregnancy?

Answer 6

• The test can show up false positives as progesterone can remain high without pregnancy (persistent CL) and can also show false negatives if poor sample storage.
• Frequent sampling is needed

Question 7

What pregnancy diagnosis test is used in the dog?

Answer 7

-Levels of relaxin

Question 8

List some of the secondary changes seen in the dam during pregnancy

Answer 8

• Teats/ mammary glands= redden/ enlarge/ wax up
• Cervical mucus= due to long period of elevated P4, mucus may become very dry and tacky
• Vaginal wall thins dye to prolonged progesterone

Question 9

In general at which point should you perform the test on the elevated milk/ plasma progesterone concentration?

Answer 9

-Days 22-24

Question 10

In general from which point do you perform most of the trans rectal pregnancy diagnostic methods in the cow?

Answer 10

• Days 28-105
• Ultrasound= day 28
• Palpation= day 25
• Membrane slip= day 35-90
• Caruncles/ cotyledons = day 80
• Uterine artery fremitus= day 1-5-210

Question 11

From which day can you perform a transrectal ultrasound on a mare?

Answer 11

Day 12-15

Question 12

From which day can you perform a transrectal ultrasound on a bitch?

Answer 12

Day 25 (also from day 25 can measure plasma relaxin)