NORMAL LEVELS OF TOTAL ESTROGENS DURING PREGNANCY IN THE MARE:


Total Estrogens test is valid after 110 days of pregnancy and its levels reflect the viability of fetal-placental unit.

DAYS OF PREGNANCY	TOTAL ESTROGENS Mean concentrations (pg/mL)
BARREN / OPEN	5-50
90 - 100	75
100 - 110	205
110 - 120	356
120 - 130	469
130 - 140	857
140 - 150	1,040
150 - 320	GREATER THAN 1,000

Normal Total Estrogens in donkeys are approximately 20% lower than Normal Total Estrogens in horses.

Approximately 2 weeks before foaling, Total Estrogens levels fall rapidly to around 300 pg/mL.