Stallions and the Law: Impregnation, Castration, Importation

In an earlier post I shared the story of a rescue mare that had been used as a test mare for imported stallions.  The method raised some issues: was it really best practices to breed healthy mares to the imported stallions as the means to test for venereal diseases (more specifically, CEM)?


Dr. Knopf castrating a donkey patient named Eeyore

I briefly mentioned the controversy to (Ribbons and Red Tape's resident veterinarian!) Dr. Knopf (see her blog posts here and here).  Prior to private practice Dr. Knopf helped perform foreign stallion entrance exams at the U.C. Davis CEM quarantine facility.  Dr. Knopf told me that:


1. Spayed mares under hormones are used for the testing (so there is no chance of pregnancy) 
2. There is no blood test for the disease
3. The stallion and the bred mare are cultured several times to ensure no evidence of the  bacteria 
4. The disease is highly contagious and could be severely damaging to the equine industry if spread through breeding
5. It is treatable, and a horse that is CEM positive can eventually be certified CEM negative.

Testing for CEM:
"Contagious equine metritis is a transmissible venereal disease of horses caused by the bacterium Taylorella equigenitalis. Undetected carrier mares and stallions are the source of the organism for acute outbreaks. Clinical signs of CEM are only manifest in the mare, never in the stallion. Because infection is often asymptomatic in mares, the disease can be difficult to detect and control. Initial infection in mares results in a period of temporary infertility, with or without signs of genital inflammation." (emphasis added)



Testing of imported stallions is legally required and is governed by the United States Department of Agriculture (USDA).  ALL imported horses (mares, geldings, etc.) are required to be in a minimum of 72 hours at a USDA quarantine facility at the port of entry (Miami, New York, or Los Angeles).  And secondly:

"[A second quarantine is not required if a stallion hasn't been in a country] where CEM is known to exist, nor have had any contact, breeding, or otherwise with horses from such country for the 12 months immediately preceding exportation. Intact horses that do not meet this requirement AND are older than 731 days of age must enter a second quarantine for CEM testing."

Eeyore after surgery, a changed man


I think the root of the controversy from this story is that it seems like the mares are being used (as one blogger noted), "like lab rats."  However, we can't fail to overlook the enormous importance of testing for this disease.  Some stallions breed to upward 100 mares a season, and if the stallion were to carry the disease, the results would be absolutely devastating to the equine community.  There was an outbreak of CEM in Kentucy in 1977, with an effect of nearly $4 million in losses to the Thoroughbred breeding industry.  The spread of equine influenza in Hong Kong in 1986 resulted in an approximate $1 billion impact on the equine industry.

Secondly, I think there is controversy over the case because after the mare was no longer a test mare, she was intended to be sent to slaughter.  Slaughter strikes a chord in horse aficionados.

And finally, I think there is controversy over the story because it seemed outrageous that this girl's horse would disappear without her consent, be sent into testing, and recovered only by chance 6 years later.  That is a horse owner's nightmare!  More on this last point in my next post (would you have to give the horse back to the original owner?)



Great information received from the UC Davis information booklet on quarantine of imported horses, which can be read online here.