FARM MANAGER’S GUIDE TO PROGESTERONE ASSAYS:
1. ESTABLISH OVULATORY STATUS OF MARES
.~ Routinely sample mares when they arrive at your farm.
.~ If Progesterone level is greater than 1.0 ng/mL, mare is
>>ovulatory.
.~ If Progesterone level is less than 1.0 ng/mL, mare is anovulatory >>or should be in heat.
.~.Check foaling mares in which foal-heat Estrus was not observed.
.~.Check any mares not showing Estrous behavior at normal
>>intervals.
2. IDENTIFY MARES WHICH HAVE EARLY FAILURE OF THE
>>PRIMARY CORPUS LETEUM
.~ Sample at day 12 post-ovulation. Values should be greater than >>4.0 ng/mL.
.~ Mares with values less than 2.0 ng/mL may have luteal
>>insufficiency, which is most likely due to uterine infection. If mare >>is not pregnant when ultrasounded, reculture reproductive tract. >>Uterine lavage may be indicated.
.~.Mares with values greater than 10.0 ng/mL likely double
>>ovulated and should be checked carefully for twins.
3. REINFORCE TESTING PROGRAM
.~ Determine status of mares missed by the teaser.
.~ Reduces amount of teasing necessary for good management.
4. DETERMINE MARES NEEDING PROGESTIN THERAPY TO
>>SUPPORT PREGNANCY
.~ Measure Progesterone levels at first ultrasound or manual
>>pregnancy check.
.~ Use Progestin Therapy in mares testing below normal for that
>>stage of pregnancy. Expect 8 to 10% to test below normal.
.~ Retest at various intervals of pregnancy to determine if mares
>>that were low in Progesterone have now become normal and
>>can be taken off progestin therapy.
5. IDENTIFY LOW PROGESTAGEN LEVELS DURING
>>PREGNANCY.
.~ Test at various stages of pregnancy. When levels are below
>>normal, retest to confirm and place on Progestin Therapy.
.~ Do not ship mares with low serum levels of Progestagens. If
>>possible, wait until at least 100 days of pregnancy before
>>shipping. If Progestagens levels are still low, place mare on
>>Progestin Therapy prior to shipping
.~ If Progestagens levels are low prior to weaning, place on
>>Progestin Therapy before weaning.
.~ If mare colics or is otherwise seriously stressed, measure
>>Progestagens.
NORMAL SERUM LEVELS OF PROGESTAGENS
AS DETERMINED BY RADIOIMMUNOASSAY
