The Journal of Animal Science has published a review article on the magnitude of the problem of unwanted horses in the U.S. The article* authored by Katie Holcomb and colleagues at the School of Veterinary Medicine University of California at Davis estimated that 100,000 horses are either abandoned or unwanted each year.
The capacity of the 326 registered nonprofit equine rescue organizations is 13,400 or approximately 14% of the annual requirement. The problems necessitating relocation of unwanted horses concern health and age since 50% of the relinquished animals show illness, injury, lameness or suboptimal body condition and their median age is 12 years.
The statistics relating to disposal of horses assembled in the JAS article illustrate the Law of Unintended Consequences. HSUS and kindred organizations have pressed for closure of horse abattoirs, precipitating the current problem that will intensify in magnitude and severity unless domestic slaughter facilities are available.
* J.Anim. Sci 88:4142-4150