Fall beef cattle disease screening

Sep 27, 2013
by WLJ

The Oklahoma Animal Disease Diagnostic Laboratory (OADDL) remains actively involved in disease surveillance for the cattle businesses of Oklahoma. OADDL is the only veterinary laboratory in the state accredited by American Association of Veterinary Laboratory Diagnosticians and routinely proficiency tested by US- DA/National Veterinary Services Laboratory for most cattle diseases in the World Organization for Animal Health (OIE) classification.

As the time for fall herd checks, pregnancy testing, and production sales approaches, we wish to offer owners and practitioners reduced rates for “herd survey” of some important bovine diseases.

The summer of 2013 has provided an escape from previous years of severe drought and many producers may contemplate retaining heifers or expanding herd size. This is an opportune time to screen incoming replacement animals or survey existing herds for Bovine Virus Diarrhea Virus, Bovine Leukemia Virus and Johne’s Disease. These “chronic” or debilitating diseases can affect over-all herd health, production and annual profits.

OADDL Fall 2013 Screening Initiative:

OADDL is offering this screening panel at a 40 percent discount! ELISA Panel for BVDV, BLV and Johne’s for only $10/head. Program requirements:

• Sample: 2.0 ml clear serum or 6.0 ml clot tube (RTT).

• Quantity: 11 animals or more on a single accession. Screening fewer than 10 animals will be charged at normal rates.

• The testing will be performed daily (Mon-Fri) in order received. Typical turn-around time for results will be 2-3 working days. Prior notification of the lab for large volume may improve efficient turn-around.

Bovine Virus Diarrhea Virus

Bovine Virus Diarrhea Virus (BVDV) generally produces either respiratory or reproductive diseases in cattle, however there are a variety of detrimental clinical outcomes when this virus is present in cattle herds. The main issue with BVDV infection a general compromise of the animal’s immune system that makes them more susceptible to other diseases.

BVDV is also unique in the “persistently infected” or “PI” animal. These animals result from being infected with BVDV during early gestation. Therefore, the PI calf is born immunotolerant and produces/ transmits abundant BVDV virus to other animals in the herd. Economic estimates for loss during acute BVDV infection in a herd vary from $50 to $100 per cow, and screening for BVDV has already become routine for many seed stock and commercial operations. Removing both PI and acutely infected animals prior to introduction to a herd is critical for positive economic and herd health impact.

Bovine Leukemia Virus (Bovine Leukosis)

Bovine Leukemia Virus (BLV) screening tests indicate high levels of exposure to BLV world-wide, although eradication efforts have been successful in cattle herds in Western Europe. USDA surveys report 13-51 percent prevalence in BLV antibodies in beef cattle operations in the U.S. BLV is best known for causing malignant lymphoma in cattle; however only 5-10 percent of BLV-infected animals develop this condition.

More importantly, the virus is associated with increased susceptibility to other infectious agents that results in decreased survival and production. This affects upwards of 30 percent of infected cattle and results in estimated losses of $59 per head in endemic areas.

In 2013, BLV antibody screening at OADDL identified 44 percent positive in individual animal screening and 73 percent positive in herd screening performed on larger groups. BLV remains an initiative for the National Cattlemen’s Association for development of control measures (CH 8.14 vaccine development). Both screening (cELISA) and confirmatory (AGID) testing are available through OADDL.

Johne’s Disease

Johne’s Disease, caused by Mycobacterium avium ssp paratuberculosis, is an infectious bacterial disease of livestock that primarily affects the intestinal tract. Cattle, sheep, and goats are most commonly affected. This chronic, generally debilitating to fatal disease is most common in Dairy cattle, but USDA prevalence data from 1997 identified 7.9 percernt of 380 beef herds tested positive for antibody. Screening at OADDL in 2013 identified 16 percent positive for antibody and 24 percent positive by PCR on feces. Submissions to OADDL probably reflect samples submitted by practitioners on cases for purposes of disease confirmation. The cooperative National Johne’s Education Initiative (NAIA, USDA, APHIS, USAHA) is endorsed by the National Cattlemen’s Association and both screening (cELI- SA) and confirmatory (PCR) testing is available at OADDL.

The lab can be reached by mail at Oklahoma Animal Disease Diagnostic Laboratory, 1812 Farm Road; OSU Campus, Stillwater, OK 74078, or by phone at 405/744-6623. — Grant B. Rezabek MPH, DVM; Pathologist, Oklahoma Animal Disease Diagnostic Laboratory