Whether we like it or not, since 2020, the general public has become increasingly informed on the topics of bioexclusion and biosecurity practice. The primary focus of bioexclusion is to prevent or limit the introduction of disease-causing agents into a herd/flock below the threshold for infection or colonization. The Equine Disease Communication Center defines biosecurity as “precautions we take to limit spread of disease when working with horses.” When evaluating the implementation of a plan, it’s important to remember that prevention and response are key when handling infectious diseases. We can all remember diligent hand washing while donning a mask.
Unfortunately, asking our equine patients to wear a medical grade mask is often met with opposition. However, it’s important to remember that transmission of disease between animals (and humans) remains very similar:
- Direct horse-to-horse (nose-to-nose) contact
- Respiratory transmission by aerosol or droplet of an agent from one horse to another
- Oral (contaminated hay, grain, or water) or contact with contaminated surfaces (stall floor mats, wells, drains, stocks)
- Venereal transmission by live cover or AI
- Fomite exposure
- Transmission of infectious agents through advanced reproductive techniques such as embryo transfer, oocyte collection, or intracytoplasmic sperm injection (ICSI)
- Vector-borne transmission (insects, ticks)
With these routes of transmission in mind, a veterinarian or mare/stallion manager must be creative when embarking on preparing a plan.
Broodmare medicine is a unique practice which includes an astute awareness of a wide variety of diseases spanning equine herpesvirus to rotavirus and clostridial enteritis. Breeding farm facilities often include horse populations from varying walks of life such as the late-term wobbling pregnant mare, the robust stallion still competing between collections, the fragile newborn soaking in its environment, and the almost weanling straying farther and farther from its dam. Due to the wide variety of at-risk populations of equine patients, managing a breeding farm biosecurity plan has many challenges. This review will touch on the primary methods for instituting a biosecurity plan and how these have been implemented at the CSU Equine Reproduction Laboratory (ERL).
How we prevent disease transmission at the Equine Reproduction Laboratory
As mentioned above, prevention and response are the two main categories to address when implementing a biosecurity protocol. Let’s break down the various levels of prevention that are within our control and how the team at the ERL is implementing action plans for each.
Vaccination
The goal of a vaccine program is to protect individuals from disease and/or protect the next generation by limiting direct vertical transmission and enhancing maternal antibody transfer.
The veterinary team at the ERL requires a rotavirus and clostridium vaccination schedule for mares enrolling in our foaling program, and heavily recommends additional core and at-risk vaccinations:
- EHV-1 (killed virus: 2 milliliters) at five, seven, and nine months of gestation
- Rotavirus (killed virus: 1 milliliter) at eight, nine, and ten months of gestation
- Clostridium perfringens C and D (2 milliliters) at nine and ten months of gestation
- EEE, WEE, EIV, EHV-1, EHV-4, WNV, tetanus toxoid (1 milliliter) at ten months of gestation
- Rabies (killed virus: 1 milliliter) at ten months of gestation
Isolation
- Examine all new horses and foals entering the premise.
- The veterinary team at the ERL requires all foals born off property accompanying their dam for reproductive services be examined prior to admittance and free from signs of respiratory or gastrointestinal disease.
- Isolate new arrivals (especially pregnant mares).
- The veterinary team works closely with the animal care team to coordinate appropriate placement of new animals within a given barn.
- Immediately isolate horses on property suspected of having a contagious disease (respiratory infection, diarrhea, or fever of unknown origin).
- Any animal within our care that displays either respiratory or gastrointestinal disease will be carefully evaluated and transitioned to separate isolation areas on property while diagnostics, therapeutics, and recommendations are created.
Traffic Control
- Determine population separation per barn.
- Each barn on property is dedicated to a specific population of horse based on their risk for infectious disease (examples: newborn foals, pregnant mares, dry mares).
- Based on this risk category, each barn is equipped with personal protective equipment (PPE) that all staff and members of the animal care team must wear.
- Create a traffic pattern.
- A customized order for moving horses in and out of the stocks is based on this risk level (example: mares with newborns enter first, followed by single mares within the same barn, etc.); the stocks are disinfected before a higher risk population is brought back in.
- Horses are fed and barns are cleaned based on at-risk populations.
- Use PPE for at-risk horses.
- Each barn is equipped with a footbath that is cleaned and changed three times daily.
- Each barn is equipped with gloves, shoe/boot covers, and/or gowns based on the at-risk population housed within.
- Students exposed to additional equine facilities must change clothes/shoes prior to working with horses at the ERL.
- Practice pest and vector control.
- Fly traps are placed within barns and examination stock areas.
- Rodent control is achieved through careful containment of feed material, strategic placement of traps, and our in-house rodent officer, Dutton, a cat.
- Limit access of visitors.
- Outpatient appointment trailers are directed to a separate examination stock area and exit through gates without travelling through the property.
- Visitation of patients is encouraged but our staff will guide owners through use of the appropriate PPE needed to interact with their newborn foals.
Sanitation
- Newborn foal population
- Upon initiation of labor, each late term pregnant mare and her neonate will be assigned a new “foaling kit” containing a garbage bag, new thermometer, umbilical dip, gloves, and hand sanitizer.
- Gowns, gloves, and overboots are required to enter the stall and interact with a newborn foal for up to five days following birth.
- Barn cleaning and sanitation
- Each foaling stall is stripped, cleaned, and disinfected completely prior to fresh shavings and a new “mom-to-be.”
- Each barn has a separate set of tools to decrease cross contamination.
- Our animal care team utilizes fresh new shavings and separate clean versus dirty buckets on skid-steer to manage waste from dirty stalls.
- Our core animal care team utilizes an “all-in, all-out” strategy at the end of the season with thorough cleaning, decontamination, and chemical disinfection when the facility is empty for every box stall on the property.
- Surveillance and monitoring
- The biosecurity team is comprised of veterinary staff, technical staff, and animal care team members working together to ensure all members are up to date with protocols and when changes are implemented.
- Any stall containing an animal(s) diagnosed with an infectious disease is fully disinfected and tested to determine the remaining presence of infectious agents.
As described above, the team at Colorado State University’s Equine Reproduction Laboratory is dedicated to keeping both this generation and future generations safe from potentially life-threatening infectious disease. With these prevention guidelines in place, the team is ready to implement an effective response to potential infections if necessary. Additional protocols are in place in the event of disease identification to minimize transmission as much as possible. None of this is possible without the dedication and collaboration between our veterinary staff, technical staff, animal care team members, and students on a daily basis.