State Veterinarians Discuss Key Health Threats at Annual WSLHA Meeting26 August 2014
US - Animal health officials have stressed the importance of diagnostics in disease-management programmes.
More than 100 veterinarian health officials and staff, laboratory personnel, invited speakers and sponsors participated in the Western States Livestock Health Association (WSLHA) Annual Meeting July 15-17, 2014, at South Lake Tahoe, Nevada.
This year, the WSLHA meeting was held with the International Livestock Identification Association Conference, which allowed both groups to meet jointly to discuss common issues concerning animal disease traceability.
According to event organizer, Kent Fowler, D.V.M., animal health branch chief, California Department of Food and Agriculture, this year’s presentations and expert-panel discussions covered diseases affecting a variety of animal species. Key topics included equine disease updates, porcine epidemic diarrhea virus, USDA-APHIS-VS reorganization update, cysticercosis, electronic Certificates of Veterinary Inspection, bovine tuberculosis, animal disease traceability, brucellosis in the Greater Yellowstone Area and trichomonosis (trich).
“It is critical for state veterinarians to meet face to face to discuss common regulatory livestock health issues, listen to different viewpoints and express opinions affecting livestock disease and movement issues,” said Fowler. “As is the case with most conferences, a lot of important discussions and business take place in the hallways between and after the meeting sessions.”
Important Role of Diagnostics
Many pressing topics involved the monitoring and management of disease, and the important role of diagnostics in optimizing health programs.
“There have been spectacular advances in biochemical technology involved in diagnosing disease, especially in the use of PCR (polymerase chain reaction) testing,” explained Fowler. “PCR technology amplifies a single or a few copies of a piece of DNA across several orders of magnitude to generate thousands or millions of copies of a particular DNA sequence, which allows increased sensitivity and specificity. When hours are critical in eliminating a highly infectious disease, a PCR diagnostic test can provide rapid diagnosis, enabling a quicker response to manage the disease.”
Jeff Baxter, senior product manager at Thermo Fisher Scientific, told the gathered state veterinarians that U.S. agriculture is so far ahead of the rest of the world in every aspect of production because U.S. farmers and ranchers have always embraced and implemented cutting-edge technology. “For example, Trich testing with the culture method is out of date, the old way of doing things,” said Baxter. “With real-time PCR methods, we can now work more effectively and efficiently in testing samples which has a significant impact on the reproduction of cow herds.”
With prices for all classes of cattle at historically high levels, Baxter says cattle producers and veterinarians must do everything they can to reliably protect these valuable investments. “Recent auction prices for calves to be delivered this fall range from $1,400 to $1,600 a head as weaned calves,” said Baxter. “The American Angus Association sold over 40,000 bulls in the past year averaging almost $5,000 a bull. So, it is clear that a positive trich bull can be very costly to producers and the industry as a whole.”
Life Technologies, a Thermo Fisher-Scientific brand, currently offers the VetMAX-Gold Trich Detection Kit, the first and only USDA-licensed, real-time PCR test to detect trich on the market.
Harmonization of trich regulations
The WSLHA devoted one morning of the meeting to lively discussion among state veterinarians around the ongoing movement to harmonize state trich regulations and procedures throughout the nation.
“Currently, there is no federal program for the control of trichomonosis, leaving it to individual state rules and regulations,” explained Fowler. “Harmonizing regulations to facilitate interstate commerce is difficult and, at times, frustrating due to varying livestock demographics and disease prevalence, along with different points of view among special-interest groups and state livestock boards.”
Though complicated, Fowler says the WSLHA has made significant progress in finding common ground in more uniform requirements for the states’ trich programs in areas such as:
• The minimum age of bulls requiring testing
• The diagnostic tests run at various laboratories
• Whether to accept pooled samples and protocols for pooled sample
• The length of time a negative trich test is valid
“Accurate, science-based diagnostic tests that are affordable are important for controlling trichomonosis and for the harmonization of cattle movement requirements,” said Fowler. “Producers must be confident that test-negative bulls purchased from any state are truly free from disease.”
Laboratory Consistency Vital
Fowler added that regulatory personnel need to be confident laboratories provide consistent, accurate results that are repeatable at laboratories in other states.
“The type of test and the specific sample-handling rules may vary depending on the availability of laboratories, prevalence of infection, the frequency of testing and the regulations for retesting, but we all need to have confidence in the test results,” said Fowler.
He explained that for many regulated diseases, USDA’s national laboratory sets the diagnostic standards that all approved state laboratories then adopt.
“Under this system, it should not matter which laboratory a sample goes to,” said Fowler. “The testing procedure is the same and the laboratory has been evaluated for competence based on uniform standards. So, one piece of the ‘harmonization challenge’ is resolved.”
Fowler pointed out that in the case of trich, there is no national laboratory, so unless all laboratories can agree on testing procedures to produce equivalent results, it will be hard for veterinarians, cattle buyers, cattle owners and animal-health officials to know exactly what a positive or negative test in different states means.
He said development of “check-test kits” that could be used to demonstrate that testing laboratories in all states provide consistent results would be helpful in harmonizing the trich program.
“Good communication between diagnostic laboratories is also important to harmonize the laboratory standards for this program that does not have national standards,” said Fowler.
Genome Sequencing Potential
Another hot topic at the WSLHA’s annual meeting was the value of whole-genome sequencing and how genetic evolution can help epidemiologists better understand the spread of disease.
“We expect to see many more advances in this area in the years to come,” said Fowler. “The knowledge we’re gaining has significant potential for evaluating the relative risk of certain production practices. Knowing how diseases spread is key to stopping that spread.”