FORTCOLLINS, COLO.—While about three quarters of equine operations vaccinated their horses in 2005,veterinarians performed the task on just half
of those farms.
TABLE 1: Percentage of equid deaths (6 months or older)
The data came from the U.S. Department of Agriculture's National Animal Health Monitoring System's (NAHMS) latest findings
of the nation's equine industry in the report, "Equine 2005: Part II: Changes in the U.S. Equine Industry, 1998-2005."
The report provides an in-depth look at vaccine use, equine census, management issues and biosecurity.
"This part of the NAHMS study allows practitioners to compare clients' equine management with national and regional estimates,"
says Josie Traub-Dargatz, DVM, professor of equine medicine and epidemiology at Colorado State University College of Veterinary
Medicine and Biomedical Sciences, who contributed to the report.
"For example, not all operations vaccinated horses. That may indicate an area where veterinarians may be able to expand (veterinary
care) to operations that didn't vaccinate."
Part II is divided into three sections:
Section I highlights demographic changes in the U.S. equine population from a historical perspective, based on data from the
National Agricultural Statistics Service (NASS),Census of Agriculture and the U.S. Census Bureau.
Section II provides data on various diseases, including equine infectious anemia (EIA),West Nile virus (WNV) and vesicular
In Section III, results from the two NAHMS studies (Equine 1998 and Equine 2005) show the evolution of U.S. equine management
Here is a synopsis of the latest (2005) report:
Section 1: Demographics
In 2002, the total number of equids on farms in the United States was 3.7 million, compared with 4.9 million in 1850. The
3.7 million represent a 19.3 percent increase from the number in the 1997 Census.
A total of 552,900 farms had equids in 2002, a 10.2 percent increase from 1997.
For comparison, the number of equid farms is three-fourths the number of farms with beef cows, six times the number of farms
with milk cows and seven times the number of hog and sheep farms.
Texas led all states with 10.2 percent of the total horses and ponies (372,300 head on 62,800 farms), followed by Kentucky,
Oklahoma and Tennessee (with about 150,000 head each).
Section II: Disease surveillance
The number of equine infectious anemia (EIA) tests performed increased to more than 2 million in 2005, attributed to greater
disease awareness, changes in testing regulations, more animal transport requiring testing and the increase in equine numbers.
The number of positive EIA tests has been declining, from approximately 4 percent in 1972 to 0.1 percent in 2005.
West Nile virus cases dropped sharply after the vaccine was fully licensed in 2003 – from 15,257 reported cases in 41 states
in 2002 to 5,181 reported cases in 2003.
Besides the vaccine, other factors contributing to the reduction include changes in the virus' ecology, increased vector control
efforts and acquired immunity by some horses.
In 2004, WNV cases dropped to just over 1,000, led by California (more than 450 per year),followed by Arizona, Nevada, and
Texas. By 2005, only Idaho and California had more than 100 cases.