United States Department of Agriculture • Animal and Plant Health Inspection Service • Safeguarding American Agriculture 

Veterinary Services 

Centers for Epidemiology and Animal Health March 2007 

_________________________________________________________________________________________________________________________ 

Trends in Biosecurity Practices 

on U.S. Equine Operations 

Biosecurity practices are vital to the health of domestic 

animals. Biosecurity practices include measures that 

reduce risk of disease introduction on an operation, such 

as controlling insect and animal vectors and isolating 

animals when they arrive or return to the operation. 

One priority in the U.S. Department of Agriculture’s 

(USDA) National Animal Health Monitoring System’s 

(NAHMS) Equine 2005 study was to compare changes 

in the equine industry from 1998 to 2005 in relation to 

biosecurity measures practiced on equine operations. 

For the Equine 2005 study, NAHMS collected data on 

equine health and management practices from a 

representative sample of operations with 5 or more equids 

in 28 States within 4 regions.* The 28-State target 

population represented 78.0 percent of equids and 78.6 

percent of operations with 5 or more equids in the United 

States. Interviews were conducted from July 18 through 

August 12, 2005, and 2,893 equine operations provided 

data on equine health and management. 

Some estimates in this information sheet are 

compared to estimates from Equine ’98, NAHMS’ 

previous study of the U.S. equine industry. For the 

evaluation of changes and trends, the data used to 

generate estimates based on the Equine ’98 study were 

re-analyzed to represent operations with five or more 

equids present on January 1, 1998. Therefore, estimates 

for comparing the two study periods are based on three 

points of commonality: same 28 States, data collection 

performed by National Agricultural Statistics Service 

enumerators, and same reference population of 5 or 

more equids. 

The percentage of operations identifying their 

primary function as “farm/ranch” increased from 30.1 

percent in 1998 to 40.3 percent in 2005, while the 

percentages of operations identifying their primary 

function as “residence with equids for personal use” 

were similar, with 38.3 percent in 1998 and 37.0 percent 

in 2005. A resident equid was defined as an equid that 

spent or was expected to spend more time at the 

operation, its home base, than at any other operation, 

whether or not it was present at the time of the interview. 

____________________________________

*Regions: 

West: California, Colorado, Montana, New Mexico, Oregon, 

Washington, and Wyoming

Northeast: New Jersey, New York, Ohio, and Pennsylvania

South: Alabama, Florida, Georgia, Kentucky, Louisiana, 

Maryland, Oklahoma, Tennessee, Texas, and Virginia 

Central: Illinois, Indiana, Kansas, Michigan, Minnesota, Missouri, 

and Wisconsin. 

General Practices 

General management practices that affect 

biosecurity on equine operations include contact with 

other animals, potential contamination of feed and water, 

and insect control. 

Contact with other animals 

A few diseases are transmitted to equids via other 

animal species. Awareness of contact between equids 

and other animal species can lead to preventive 

measures and a more timely response to a disease 

outbreak. 

The percentage of operations where poultry had direct 

contact with resident equids or their feed increased from 

13.4 percent in 1998 to 18.6 percent in 2005 (table 1). The 

percentage of operations where cattle had direct contact 

with resident equids or their feed increased from 34.1 

percent in 1998 to 43.2 percent in 2005. The increase in 

equid contact with cattle and poultry may be a result of the 

higher percentage of operations with farm/ranch as a 

primary function in 2005 compared to 1998. 

Table 1. Percentage of operations where the listed 

animals had physical contact with resident equids or 

their feed: 

Percent Operations 

1998 2005 

Animal Percent Percent 

Poultry 13.4 18.6 

Pigs 3.7 4.7 

Cattle 34.1 43.2 

Sheep/goats 11.4 13.9 

Llamas/alpacas 1.5 2.4 

Emus/ostriches 1.0 1.2 

Dogs 77.9 76.9 

Cats 67.7 66.4 

Feed and water management 

Contamination of feed and water by outside sources 

is a potential route of infection for equids. The 

percentage of operations that fed grain 

concentrate/energy source beyond hay or pasture during 

the previous 12 months was slightly higher in 1998 than 

in 2005 (95.9 percent and 90.1 percent, respectively). 

For operations that fed grain concentrate/energy 

source during the previous 12 months, the percentage of 

grain/concentrate by feed source was averaged over all 
United States Department of Agriculture • Animal and Plant Health Inspection Service • Safeguarding American Agriculture 

operations. The highest percentage was purchased in 

bags from a retail source in both 1998 and 2005 (82.5 

percent and 79.1 percent, respectively). Intact bags 

should provide a layer of protection against possible 

contamination. Other sources of grain 

concentrate/energy source included bulk delivery from a 

retail source (6.3 percent in 1998 and 9.6 percent in 

2005) and home-grown (7.4 percent in 1998 and 7.9 

percent in 2005). 

The percentage of operations that stored 

grain/concentrate in a manner to prevent fecal 

contamination by mice or rats increased from 77.6 

percent in 1998 to 85.0 percent in 2005. In 1998, the 

questionnaire asked if feed was stored in rodent-proof 

containers, and the change from more-specific to lessspecific wording might account for some of the increase. 

The main sources of drinking water for equids were 

similar in 1998 and 2005, with well water being the 

predominant source of water for equids on more than 

half the operations in both 1998 and 2005 (table 2). 

Surface water presents the greatest concern of 

disease exposure because it is difficult to control water 

quality; about one-fifth of operations in each study used 

surface water as the primary water source for equids. 

Table 2. Percentage of operations by predominant

source of drinking water for resident equids during the 

previous 12 months: 

Percent Operations 

1998 2005 

Source Percent Percent 

Well 58.9 57.5 

Public/municipal 

water supply 17.2 18.9 

Spring 5.2 5.4 

Surface water 

(pond, stream, river, 

or cistern) 18.2 18.1 

Other 0.5 0.1 

Total 100.0 100.0 

Insect control 

Insect control is vital to the health of equids. Insects 

transmit disease agents, and large infestations of insects 

can weaken an equid’s immune system. For both 

studies, approximately 9 of 10 operations practiced 

some form of insect control. The listed methods of insect 

control were not mutually exclusive, as operations could 

have used various combinations of insect control. 

The most common method of insect control reported 

in both studies was repellents applied to equids, 

although its use decreased from 86.5 percent in 1998 to 

73.1 percent in 2005 (table 3). The percentages of 

operations that used insecticides applied in or near 

equine housing area and insecticides applied on 

pastures increased from 1998 to 2005. Several methods 

of insect control that were common “write-in” methods in 

1998 were added to the 2005 questionnaire: bug zapper, 

fly sheet on equids, mosquito treatment in drinking 

water, water container emptied at least weekly, frequent 

removal of manure and weeds from premises, and 

screened-in stalls. Two of these options—water 

container emptied and refilled with fresh water at least 

weekly and frequent removal of manure and weeds—

were the second and third most frequently used methods 

of insect control in 2005. The methods added in 2005 

probably account for the decrease from 1998 to 2005 in 

the percentage of operations that listed “other” as a 

method of insect control. 

Table 3. Percentage of operations where the listed 

insect-control methods were used during summer: 

Percent Operations 

1998 2005 

Method Percent Percent 

Repellents 

applied to equids 86.5 73.1 

Insecticides applied 

in or near equine 

housing area 26.1 36.0 

Insecticides applied 

to pasture areas 1.2 5.5 

Regional control 

program, such as 

aerial spraying 2.5 4.1 

Sticky tape 26.7 20.9 

Bug zapper N/A 8.4 

Parasitic wasps 

specifically brought 

onto operation 2.4 3.1 

Face mask on equid 32.3 27.2 

Fly tags attached 

to equine halters 3.5 4.1 

Fly sheets on equid N/A 7.3 

Insect control product 

in feed, such as 

using Equitrol® 2.8 5.6 

Mosquito treatment 

in drinking water 

(mosquito dunks) N/A 6.3 

Water container 

emptied and refilled 

with fresh water at 

least weekly N/A 58.5 

Frequent removal of 

weeds and manure 

from premises N/A 51.3 

Screened-in stalls N/A 2.4 

Other 13.1 5.9 

Any method 91.3 88.9 

Practices Related to Introduction of Equids on 

the Operation 

Contact between resident and other equids is one 

means of disease transmission. The percentage of 

operations that introduced a new animal—either a 
United States Department of Agriculture • Animal and Plant Health Inspection Service • Safeguarding American Agriculture 

nonresident and/or a new resident—during the previous 

12 months decreased from 50.4 percent in 1998 to 33.6 

percent in 2005. A nonresident equid was defined as an 

equid that visited the operation for fewer than 30 

consecutive days during the previous 12 months. A new 

resident equid was defined as a purchased animal, a 

new boarder, or other acquired equid considered from 

that point on to be a resident. For operations that 

introduced equids in 1998, about 0.80 nonresident or 

new resident equid was introduced for each resident 

equid; in 2005, approximately one (0.95) nonresident or 

new resident equid was introduced for each resident 

equid. The increase in introduced equids relative to 

residents—despite the decline in the percentage of 

operations introducing a new equid—might reflect the 

decrease in the percentage of large operations (20 or 

more equids) from 39.4 percent in 1998 to 29.7 percent 

in 2005. 

Nonresident equids 

The percentages of operations with 0, 1 to 9, and 10 

or more nonresident equids that stayed fewer than 30 

consecutive days were similar in 1998 and 2005 (table 

4). Approximately 8 of 10 operations in 1998 and 2005 

had no nonresident equid visitors during the previous 12 

months. For operations that had nonresident equids, the 

majority had fewer than 10 nonresident equids visit 

during the previous 12 months. 

Table 4. Percentage of operations by number of nonresident equids that stayed on the operation for fewer than 

30 consecutive days during the previous 12 months: 

Percent Operations 

1998 2005 

Number 

Nonresident 

Equids Percent Percent 

0 79.1 81.0 

1 to 9 15.4 14.7 

10 or more 5.5 4.3 

Total 100.0 100.0 

Methods that reduce the risk of nonresident equids 

introducing disease agents to an operation include 

evaluation of the health status of nonresidents (e.g., 

through exams, preventive treatments, and/or testing 

requirements), vaccination and deworming 

requirements, and quarantine or isolation prior to contact 

with resident equids. 

For operations that had nonresident equids that stayed 

fewer than 30 consecutive days, the percentages of 

operations that implemented the health requirements listed 

in table 5 for nonresident equids were similar in 1998 and 

2005. In both studies, the most common health 

requirements implemented at least some of the time for 

nonresident equids were a Coggins test for equine 

infectious anemia (EIA), vaccination, and deworming 

within the past year. In 2005, three choices were added to 

the health-requirement category: screening test for 

strangles or history of no occurrence in past 6 months, 

other past medical history, and quarantine prior to contact 

with resident equids. It is unlikely that these additional 

choices altered the response to the other choices because 

the choices for health requirements were not mutually 

exclusive (e.g., operations could implement more than one 

of the requirements for nonresident equids). 

Table 5. For operations with nonresident equids that stayed 

for fewer than 30 consecutive days during the previous 12 

months, percentage of operations by frequency that the 

following health requirements were always or sometimes 

implemented for the majority of nonresident equids: 

Percent Operations 

1998 2005 

Health Requirement Percent Percent 

Official health 

certificate (CVI) 31.9 24.8 

Veterinary examination 

other than CVI 30.7 18.4 

Coggins test 

(EIA test, swamp fever test) 50.2 45.3 

Vaccination within past year 43.5 36.3 

Deworming within past year 43.2 33.6 

Screening test for strangles 

or history of no occurrence 

in past 6 months N/A 9.7 

Other past medical 

history from owner N/A 21.8 

Quarantine prior to 

contact with resident equids N/A 17.2 

Other 10.6 3.8 

New resident equids 

The percentage of operations that added new 

resident equids and the percentage of resident equids 

added both decreased from 1998 to 2005 (table 6). 

Operations with primary functions of farm/ranch and 

residences with equids for personal use accounted for 

much of the difference, with a smaller percentage of 

operations with these primary functions indicating 

addition of new residents in 2005 compared to 1998. 

Table 6. Percentage of operations that added new 

resident equids during the previous 12 months and 

percentage of equids added, including foals not born to a 

resident mare (excluding births): 

Percent 

1998 2005 

Measure Percent Percent 

Operations 40.5 21.5 

Resident equids* 11.3 6.3 

*Total number of equids added to resident equine population x 

100/total resident equine inventory. 
United States Department of Agriculture • Animal and Plant Health Inspection Service • Safeguarding American Agriculture 

For both studies, operations that added new resident 

equids during the previous 12 months most commonly 

required a Coggins test for EIA for new additions at least 

some of the time; a similar percentage of operations 

required a Coggins test in each study (table 7). 

Vaccination remained an important requirement. The 

percentage of operations requiring deworming within the 

past year decreased, as did the percentages of operations 

requiring a CVI or other veterinary examination. As noted 

previously, three additional choices for health 

requirements were added in 2005: screening test for 

strangles or history of no occurrence in past 6 months, 

other past medical history from owner, and quarantine 

prior to contact with resident equids. The healthrequirement choices were not mutually exclusive, so it is 

unlikely that responses to the first five categories were 

influenced by the new choices. The percentage of “other” 

requirements decreased from 13.0 percent in 1998 to 5.0 

percent in 2005, likely because of the above-mentioned 

choices added to the 2005 questionnaire. 

Table 7. For operations that added new resident equids 

during the previous12 months, percentage of operations 

that always or sometimes implemented the following 

health requirements for new additions: 

 Percent Operations 

 1998 2005 

Health Requirement Percent Percent 

Official health 

certificate (CVI) 53.1 34.6 

Veterinary examination 

other than CVI 45.1 29.2 

Coggins test (EIA test, 

swamp fever test) 67.2 61.8 

Vaccination within 

past year 57.0 49.2 

Deworming within 

past year 65.8 48.9 

Screening test for 

strangles or history of 

no occurrence in past 

6 months N/A 14.2 

Other past medical 

history from owner N/A 36.3 

Quarantine prior 

to contact with 

resident equids N/A 32.0 

Other 13.0 5.0 

Practices Related to Contact with Equids Off 

the Operation 

The percentage of operations where resident equids 

left the home operation and returned after having direct 

contact with outside equids decreased from 87.3 percent 

in 1998 to 75.1 percent in 2005. Equids that leave the 

home operation and have contact with outside equids 

may be exposed to disease agents and introduce these 

agents to the home operation upon return. Isolating 

returning equids is one way to prevent this type of 

disease introduction. 

For operations that had resident equids that left the 

home operation and returned after direct contact with 

outside equids, the percentages of operations that 

routinely isolated returning equids were similar in 1998 and 

2005 (table 8). The percentage of operations that isolated 

returning equids due only to disease or exposure to 

disease increased from 15.8 percent in 1998 to 26.0 

percent in 2005. The percentage of operations that never 

isolated returning equids decreased from 72.3 percent in 

1998 to 60.6 percent in 2005. 

Table 8. For operations that had resident equids that left 

the home operation and returned after direct contact with 

outside equids, percentage of operations by infectioncontrol practice used for returning equids: 

Percent Operations 

1998* 2005 

Infection-Control Practice Percent Percent 

Routinely isolate 

returning equids 11.9 10.6 

Only isolate returning equids 

for a cause such as disease 

or exposure to disease 15.8 26.0 

Quarantine before arrival at 

home operation N/A 2.8 

Never isolate 

returning equids 72.3 60.6 

Total 100.0 100.0 

*Categories for 1998 were resident equine never leave premises, 

routinely isolated returning equine, isolated returning horses for a 

cause such as evidence of or exposure to disease, and never isolated 

returning horses. 

____________________ 

For more information, contact: 

USDA:APHIS:VS:CEAH 

NRRC Building B, M.S. 2E7 

2150 Centre Avenue 

Fort Collins, CO 80526-8117 

970.494.7000 

E-mail: NAHMS@aphis.usda.gov 

http://nahms.aphis.usda.gov 

#N474.0207 

____________________________________ 

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