Quantitative progesterone
is measured in a serum sample taken 18 - 25 days post
service. Progesterone levels >13.0 nmol/L are highly suggestive
of pregnancy at this time, levels <3.0 nmnol/L are likely
to be non-pregnant. This is very useful for thoroughbred
mares, where time is critical and who need to be returned
to the stallion for further mating.
Progesterone can also be used in other ruminants who cycle
every 21 days.
NOTE: Bovine samples for progesterone
must be taken as clotted blood and separated as soon as
possible. Heparinised bovine blood samples will have falsely
low progesterone levels due to the red blood cells metabolising
the progesterone.
Equine Pregnant
Mare Serum Gonadotrophin (PMSG)
NOTE:
SERUM sample MUST be used for PMSG
PMSG is produced from the endometrial cups from about
day 40 - 120 post covering and is the next available pregnancy
test. PMSG is prone to false positives as, if the foal
dies, the endometrial cups continue to produce PMSG for
some time. O-SO4 should be used to confirm pregnancy and
the presence of a live foal after 100 days.
Equine Oestrone
Sulphate Pregnancy Test
Oestrone Sulphate can be used as
a very sensitive pregnancy test in horses and demonstrates the
presence of a live foal, if the foal dies the Oestrone Sulphate
decreases very rapidly. Oestrone Sulphate starts to rise from
about 80 days post covering, increases steadily to above 25
ng/mL and remains detectable until very close to term.
Oestrone Sulphate may also be used in cows and donkeys as a
late pregnancy test and in goats to distinguish between true
pregnancy and "cloudburst".
Pigs have an early Oestrone Sulphate peak about 35 - 45 days
and again at >100 days.
Total Urinary Oestrogens
Total Urinary Oestrogens may be
used as a late pregnancy test (>100 days gestation) as there
are very large concentrations of a variety of oestrogens excreted
in the urine in late pregnancy. This is also applicable to a
wide range of species.
Summary Table
of Equine Pregnancy Tests
Days Gestation
Test
Use
18 - 25
Progesterone (quantitative)
Early - first indication
40 - 120
PMSG (quantitative)
Next - good indication
>100
Oestrone Sulphate
Middle/Late - very accurate
>100
Total Urinary Oestrogens
Middle/Late - urine test
Canine Pregnancy
Test - Relaxin
Non-pregnant bitches have significant
levels of progesterone as part of their normal cycle (metoestrus),
therefore progesterone alone cannot be
used as a canine pregnancy test.
Relaxin is very specific to pregnancy and so can be used as
an accurate pregnancy test. Following conception relaxin rises
to detectable levels from about 21 - 28 days. It is advisable
to take blood samples at around 28 days post mating as this
will allow for the difference in conception dates. Small litter
size (=<3) may result in false negative results.
Sample required is 0.5mL HEPARIN plasma
(EDTA plasma MUST NOT be used).
Feline Pregnancy
There is no specific pregnancy test
for cats. Progesterone may be analysed but this will only indicate
if the cat is non-pregnant (Progesterone <3.0 nmol/L).
