8 Colo. Code Regs. § 1201-19, pt. 11

Current through Register Vol. 47, No. 22, November 25, 2024

Part 11 - Equine Viral Arteritis

11.1. Definitions

11.1.1. "Approved laboratory" means a laboratory approved by the State Veterinarian to conduct official testing for equine viral arteritis.

11.1.2. "Book" or "booking" means the contracting or scheduling of a mare to be bred to a stallion.

11.1.3. "Carrier" means a stallion that has a positive EAV virus isolation test or polymerase chain reaction (PCR) test from semen.

11.1.4. "EAV" means equine arteritis virus, the organism that causes the disease equine viral arteritis.

11.1.5. "Equidae" means all members of the genus Equus which includes but is not limited to horses, asses, hinnies, mules, donkeys, burros, ponies, and zebras.

11.1.6. "EVA" means equine viral arteritis, a communicable disease in equine resulting in abortion in pregnant mares, illness and death in young foals, and potential establishment of the carrier state in stallions.

11.1.7. "Isolated" means the protocols to prevent the transfer of EAV through the appropriate separation, movement controls, and biosecurity procedures approved by the State Veterinarian.

11.1.8. "ISO compliant microchip" means a microchip used to identify individual Equidae that are compliant with the International Organization of Standardization and the USDA's animal disease traceability requirements.

11.1.9. "Owner" means any person with the legal right of possession or having legal control over any Equidae, and shall include but not be limited to agents, caretakers, and other persons acting on behalf of that person.

11.1.10. "PCR test" Polymerase chain reaction test to detect EAV in samples.

11.1.11. "Semen" Secretion or ejaculate from the reproductive tract of a stallion containing spermatozoa and seminal fluid from the accessory sex glands.

11.1.12. "Sero-negative test mare" means a mare that has been tested sero-negative (SN titer < :4) and has been isolated from other horses for 21 days prior to being bred.

11.1.13. "Sero-negative" means a horse that has tested negative (SN titer < :4) to a blood test for antibodies to EAV.

11.1.14. "Sero-positive" means a horse that has tested positive (SN titer >=1:4) to a blood test for antibodies to EAV.

11.1.15. "Shedder" or "shedding" means an Equidae has been determined to have EAV in its body and has potential of transmitting the EAV to other Equidae.

11.1.16. "Stallion" means a sexually intact male Equidae.

11.1.17. "Standard insemination volume" means 10 ml of semen.

11.1.18. "Test breeding" means breeding a suspect carrier stallion to 2 sero-negative mares a minimum of twice a day for two (2) - to four (4) days in the same estrus period.

11.1.19. "Vaccinated" or "vaccination" means an Equidae has been vaccinated with the approved EVA modified live virus vaccine and the vaccination status has been kept current in accordance with the manufacturer's recommendations.

11.1.20. "Vaccinated sero-positive stallion" means a stallion that was sero-negative prior to being vaccinated against EVA and which has a positive titer (>1:4) post vaccination.

11.2. General EVA Information

11.2.1. All laboratory samples pertaining to this rule shall be submitted by an accredited veterinarian to an approved laboratory.

11.2.2. It is recommended that all breeding stallions be tested for EAV prior to use as a breeding stud or collection for artificial insemination.

11.2.3. It is recommended that frozen semen or semen from unknown stallions be tested negative by virus isolation or PCR prior to being used for artificial insemination.

11.3. EVA Shedding Stallions

11.3.1. A stallion is considered to be a carrier if any of the following apply: the virus can be cultured from his semen, if the virus can be detected in his semen by PCR test, or if sero-negative mares seroconvert to sero-positive status within 28 days following breeding or insemination.

11.3.2. A stallion known to be a carrier shall not be permitted to breed or be collected for artificial insemination until the State Veterinarian determines that the stallion does not pose a risk of transmitting EAV. In making this determination, the State Veterinarian shall consider whether the requirements of Parts 11.3.2.2. and 11.3.2.3. of this section will be complied with by the premises on which the carrier stallion is located. The following restrictions shall apply to a carrier stallion that is permitted to breed or be collected for artificial insemination:

11.3.2.1. The owner or agent of an EAV carrier stallion shall notify in writing the owner or agent of a mare booked or seeking to book a mare to that stallion that has been classified as an EAV carrier. A written copy of the booking confirmation shall be sent to the State Veterinarian.

11.3.2.2. A carrier stallion shall be housed, handled, and bred or collected for artificial insemination in a facility isolated from non-shedding stallions.

11.3.2.3. A carrier stallion shall be bred to a mare(s) that:

11.3.2.3.1. Have been vaccinated against EVA at least twenty-one (21) days and not more than 1 year prior to being bred; or

11.3.2.3.2. Has an existing EAV titer from vaccination or natural exposure to EAV, if the serological test for EVA was performed prior to date of breeding.

11.4. Sero-Positive Non-shedding Stallions

11.4.1. A stallion may be considered to be a 'vaccinated sero-positive stallion' if a blood sample collected within 10 days prior to administration of an approved vaccine was negative (SN titer < :4) for antibodies to EAV. See Section VIII for recommended vaccination protocols.

11.4.2. It is required that a sero-positive vaccinated stallion that did not have an EVA negative test prior to vaccination comply with one of the following testing procedures to ensure that the stallion is not at risk of transmitting the virus:

11.4.2.1. A standard insemination volume (10ml) of semen should be collected and either virus isolation tested for EAV or evaluated using a PCR test; or

11.4.2.2. The stallion should be bred to two (2) mares negative for EAV antibodies. The two (2) mares should have blood collected for an EVA test twenty-eight (28) days after breeding or artificially inseminated from two ejaculates, separately collected.

The sero-positive stallion would be considered a non-carrier if the semen virus isolation tested, semen PCR or test-breeding results are negative.

11.4.3. A stallion may be considered a 'non-vaccinated sero-positive stallion' if the stallion has seroconverted following a natural exposure to the virus. It is required that a non-vaccinated sero-positive stallion be tested as outlined below prior to breeding to ensure that he is not at risk of transmitting the virus.

11.4.3.1. Semen should be collected and either tested by virus isolation or evaluated using a PCR test for EAV; or

11.4.3.2. The stallion should be bred to two (2) mares negative for EAV antibodies. The two (2) mares should have blood collected for an EVA test twenty-eight (28) days after breeding or artificial insemination.

11.4.3.3. The sero-positive stallion will be considered a non-carrier if the semen by virus isolation, PCR, or test breeding results is negative.

11.4.4. A stallion previously classified as a carrier stallion may be re-classified as a non-carrier stallion if the following criteria are met:

11.4.4.1. During the first breeding season following the stallion's classification as a non-carrier, the first five (5) sero-negative mares bred or artificially inseminated using semen collected from separate ejaculates from this stallion shall be test negative to a blood sample collected for an EVA test twenty-eight (28) days after breeding or artificial insemination.

11.4.4.2. During the second breeding season, the stallion shall be bred to two (2) mares negative for EAV antibodies that will be tested twenty-eight (28) days after breeding or have its semen collected and be virus isolation negative for EAV or have the semen tested negative by PCR for EAV. If the semen virus isolation test or PCR test and blood samples are negative for EAV, there shall not be restrictions placed on a future breeding season.

11.4.5. The final determination that a stallion is not an EAV carrier shall be made based on scientific procedures described in this section and approved by the State Veterinarian. Until this determination is made the stallion shall be considered as an EAV carrier.

11.5. Requirements for Breeding Mares to a Carrier Stallion or Inseminating Mares with Known EAV Infected Semen

11.5.1. The following guidelines are required when breeding mares to a carrier stallion or inseminating mares with known EAV infected semen.

11.5.1.1. If a sero-negative mare is to be bred to a carrier stallion for the first time.

11.5.1.1.1. It is required that the mare be vaccinated a minimum of twenty-one (21) days prior to the first breeding or artificial insemination by an EAV carrier stallion and subsequently isolated a minimum of twenty-one (21) days after the first breeding or artificial insemination.

11.5.1.1.1.1. During isolation, the mare shall be physically separated from other Equidae in a separate isolation area approved by the State Veterinarian or designated personnel.

11.5.1.1.1.2. After the isolation period, the mare may move without restriction.

11.5.1.2. Mares that have been vaccinated against EAV or have been bred to an EAV carrier stallion within the previous two (2) years may be re-bred to a carrier stallion but should be isolated for a minimum of twenty-one (21) days after breeding as noted above.

11.5.1.3. When a mare bred to a carrier stallion is returned to the premises of origin within 21 days of breeding, it shall be in a transport vehicle or trailer by herself or with other sero-positive Equidae. Upon returning to the premises of origin, the transport vehicle or trailer and equipment used to move the mare must be immediately cleaned and disinfected according to procedures approved by the State Veterinarian.

11.6. Actions for Newly Diagnosed Sero-positive Stallions

11.6.1. A stallion infected with EAV during the breeding season shall immediately cease breeding or immediately cease having semen collected for artificial insemination or semen collected and stored for future use. Since EVA is a reportable disease in the State of Colorado, the State Veterinarian must be immediately notified in the event of clinical EVA disease demonstrated by a positive laboratory test on serum or semen. An owner or agent with a mare booked or bred to a stallion that became infected with EAV during the breeding season shall be immediately notified in writing by the stallion's owner or agent. A copy of the written notification shall be sent to the State Veterinarian. A stallion infected with EAV during the breeding season shall be classified as an EAV carrier and shall be handled according to the requirements of this rule. Following the stallion's classification as a carrier, the State Veterinarian may reclassify the stallion as a non-carrier in accordance with this rule.

11.7. Equidae Vaccinated Against EVA

11.7.1. Following are the recommendations that will provide for a more effective program for mares or stallions to be vaccinated for EVA in Colorado:

11.7.1.1. The Equidae owner's facility should have a premises identification number (PIN).

11.7.1.2. The mare or stallion receiving EVA vaccine should have an ISO compliant microchip implanted according to USDA's animal disease traceability requirements.

11.7.1.3. That mares be tested for antibodies to EAV prior to an initial EVA vaccination.

11.7.1.4. Testing for antibodies in blood of mares be submitted to an approved veterinary laboratory.

11.7.1.5. A certificate documenting the mare has been vaccinated be sent to the State Veterinarian within seven (7) days of the vaccination date.

11.7.1.6. The EVA vaccination certificate for mares should be on a form prescribed by the State Veterinarian.

11.7.1.7. The prior negative EVA test and vaccination of intact colts between 6-12 months of age and of adult teaser stallions.

11.7.2. Following are the requirements for mares or stallions to be vaccinated with EVA vaccine in Colorado:

11.7.2.1. Testing of stallions for antibodies in blood or evidence of EAV in semen shall be submitted to an approved veterinary laboratory.

11.7.2.2. Stallions vaccinated for the first time against EVA shall be test negative to a blood sample collected by an accredited veterinarian prior to vaccination.

11.7.2.3. Stallions vaccinated for the first time against EVA shall have the EVA vaccine administered by an accredited veterinarian within ten (10) days after the sample collection date.

11.7.2.4. A certificate documenting that the stallion has been vaccinated shall be sent to the State Veterinarian within seven (7) days of the vaccination date.

11.7.2.5. The EVA vaccination certificate for stallions shall be on a form prescribed by State Veterinarian.

11.7.2.6. All Equidae vaccinated for the first time against EVA shall not have direct exposure to an EVA affected animal or a pregnant mare for twenty-one (21) days after vaccination.

11.7.2.7. A vaccinated stallion shall not be used for breeding or artificial insemination within twenty-eight (28) days after vaccination. A vaccinated mare shall not be bred within twenty-one (21) days of vaccination.

11.8. EVA Test Mares

11.8.1. An EVA test mare shall be isolated from the other Equidae and under the supervision of the State Veterinarian if the mare becomes:

11.8.1.1. Clinically affected with EVA after breeding or artificial insemination; or

11.8.1.2. Sero-positive after breeding or artificial insemination.

11.8.2. An isolated mare shall be released from isolation by the State Veterinarian after:

11.8.2.1. Twenty-eight (28) days in isolation and providing test results are negative; or

11.8.2.2. The spread of EAV is no longer a risk, whichever is longer.

8 CCR 1201-19, pt. 11

37 CR 23, December 10, 2014, effective 12/30/2014

39 CR 13, July 10, 2016, effective 7/30/2016

40 CR 23, December 10, 2017, effective 12/30/2017

44 CR 10, May 25, 2021, effective 6/15/2021

46 CR 15, August 10, 2023, effective 9/15/2023