Pregnant Mare Urine (PMU)

• The estrogen compounds contained in Hormone Replace Therapy drugs such as Premarin are sourced from the urine of pregnant mares.
• Urine is collected by ranchers and then purchased by pharmaceutical companies to make estrogen based drugs.
• The pharmaceutical corporation Pfizer is the producer of the PMU brand Premarin 

PMU Technology and Knowledge

Urine from pregnant mares is collected for 160-180 days. The urine collection system is suspended from the ceiling and is a funnel-like device positioned under the tail and between the rear legs.

The mares are stand tied in stalls limiting the chance of disconnecting the urine collection system (Houpt & Waran, 2003)

Ranchers’ contracts are in grams of estrogen, not unit volume of urine (NAERIC, 2015) and mares may produce between 90-100 gallons per collection season. A draft mare may produce more than other mare breeds per day and per season. Following parturition, the mares are returned to field with their foals and become pregnant again in the following season.