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Horses - Premarin

premarin foal hoistedA Premarin foal hoisted for slaughter
Photo Courtesy: Horse Aid
Hormone replacement drugs Premarin (Pregnant Mare's Urine) and the Premarin family of products, which include Prempro, Prempak-C and Premphase, are used to treat menopausal symptoms in women. Manufactured by Wyeth Pharmaceuticals (part of Pfizer since January 2009), Premarin uses conjugated equine estrogens (CEEs) as the hormonal component.

Harvested for their urine, the horses suffer terribly for the production of this drug. They are kept continually pregnant in stalls too small for them to even turn around in order for their urine to be collected by filthy, bulky tubing attached to their bodies. When they can no longer reproduce quickly they are sent to the slaughterhouse. Their meat is then sold for human consumption or dog food.

Pfizer reported over $1 billion in worldwide sales of the Premarin family of drugs in 2010. Due in part to falling sales and the controversy over Premarin and its side effects (the Women's Health Initiative has done numerous studies on the health impacts of Premarin products); Pfizer is conducting clinical trials on another hormone replacement drug called Aprela, which if approved. Aprela is a combination product composed of the SERM (selective estrogen receptor modulator) Bazedoxifene and CEEs. Bazedoxifene has been approved in the EU and Japan but its approval by the FDA in North America has repeatedly been postponed due to complications of stroke and venous thrombotic events. It is estimated that there will be the same amount of CEEs in Aprela as there is in Premarin.

The number of pregnant mare urine (PMU) farms in North America decreased in 2010, from 400 farms at the peak of manufacture in 2003, to 26 ranches, but this news is tempered by rumors of PMU farms emerging in places where horse slaughter is generally accepted such as China, Kazakhstan, and Poland.

premarin urine collectionMare with a urine collection device strapped to her bodyLiving Conditions

At PMU farms –- found in Canada and North Dakota -- mares in their third or fourth month of pregnancy are placed alone in narrow stalls. They are fitted with a short rope or chain, a harness, and a urine collection bag which scrapes their legs, causing sores. As a result of these restrictive devices, the mares are made virtually immobile. They can take only a step or two in any direction and are unable to turn around or lie down comfortably.

Because farmers find sufficient bedding costly and bothersome to clean, the animals frequently have no protection from the cold concrete floor. Moreover, farmers restrict the amount of water given to the mares because water dilutes the concentration of their urine, making it less profitable. Their food supply is similarly inadequate, and they do not receive sufficient veterinary care. Most mares are never removed from the stall and allowed to graze. Deprived of exercise, they cannot utilize their natural athleticism and sociability, kick up their heels, stretch their muscles, or flex their joints.


The vast majority of Premarin mares give birth to a foal every year. Afterwards, they are almost immediately impregnated again. If they fail to become pregnant, they are sent to slaughter. If they do become pregnant again, their foals are taken from them at the premature age of just three to four months. Most mares naturally resist separation from their babies so they are often whipped, kicked, or beaten with an electric prod until they finally allow their foal to be taken.

prem foal carcassFoal carcass at a slaughterhouse FoalsFoals

Some foals are killed immediately after birth. A few of the females will be raised to be "Premarin mares" and join the production line. Most will be sold and sent to feedlots to be fattened for slaughter, then transported by trailer to slaughterhouses and killed. Their meat will be shipped off to Japan, France, or other parts of Asia and Europe for human consumption.


Like other "food animals," mares and foals are typically deprived of food and water during transport to the slaughterhouse. They do not have an opportunity to rest, nor do they receive veterinary care. Instead, they are crammed onto trailers so crowded that the smaller ones, particularly the foals, are sometimes crushed under larger animals. Those that are too weak to stand will literally be dragged off of the truck along with the animals that have died en route.

Corporate Greed

Thousands of horses suffer to produce Premarin even though several humane estrogen replacement therapies exist (see below under "What You Can Do" for alternatives). Why don't Premarin manufacturers switch to a cruelty-free alternative? Because they say it would cost them more money.

The Law

Animal cruelty laws and government regulations do not apply to the treatment of mares on Premarin farms. Instead, the standard of care is dictated only by an inadequate "code" which is poorly enforced. Thus the horses receive virtually no legal protection.

prem overgrown hoovesOvergrown hoovesHealth Problems Common to Mares Used in Premarin Production

  • Dehydration
  • Hoof injuries
  • Leg injuries, sores, and lacerations
  • Swollen joints
  • Edema
  • Liver disorders
  • Kidney disorders
  • Premature death

Behind the Scenes Video

premarin video auctions premarin video butchering premarin video feedlots
premarin video foals to slaughter premarin video lagoon premarin video peebarns
premarin video slaughter corrals    

What You Can Do:

  • Make the Switch
    If you currently take Premarin, Prempak-C, or Premphase, ask your doctor about equally effective synthetic or plant-based alternatives such as:
    • Cenestin
    • Estrace
    • Estraderm
    • Ogen
    • OrthoEst
    • Estratab
    • Menest
    • Estinyl
    • Estrovirus
    • OrthoDienestrol
    • Tace
    • Climara

  • Make Some Noise –
    Contact Ian Read, Chairman & CEO of Pfizer. Demand Pfizer produce a more humane product!
    Ian Read
    Chairman, CEO
    Pfizer Inc
    235 East 42nd Street
    New York, NY 10017
    Phone: 1-212-733-2323

    Please send a copy of the letter to LCA's Campaigns Department at our mailing address, fax, or via email at This email address is being protected from spambots. You need JavaScript enabled to view it.

    Write a letter to your local newspaper about the cruelty of Premarin production, and the safe alternatives available to women.
    Educate others about the suffering inherent in Premarin production.

  • Go Vegan
    A healthy vegan diet can reduce menopausal symptoms, especially those diets supplemented by soy products containing plant-based estrogens.

For More Information:


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