Herd Health: Biosecurity Review for Cattle Producers

Biosecurity

All producers aim to maintain the health of their herds. Because losses from sickness and death take a toll on cattle and producers alike, it can be helpful to review farm biosecurity practices periodically.

Recently, two farms sent beef cattle for necropsies (autopsies) to the state veterinary diagnostic laboratory (Clemson Veterinary Diagnostic Center) to determine the cause of death.

Farm #1 purchased some cattle and “separated” them from the main resident herd. About one week after arrival, numerous resident cattle became sick — several very sick. Some of these animals became sick overnight and died before treatment could be started. A few days later, several of the recently purchased cattle became sick, and some were lost.

Farm #2 purchased a bull from a known source with a similar, good herd health program (vaccinated against blackleg and 9-way (IBR/PI3/BVD/BRSV/Lepto5)). The bull was placed directly with the cows that had recently calved. About two weeks later, calves displayed respiratory signs “overnight.”

What could have happened to contribute to disease introduction in these two instances?

It was realized that the “separation” on Farm #1 was a fence that could allow nose-to-nose contact between the new arrivals and the home herd, so it did not provide true isolation. Unfortunately, because there was no vaccination history for either the new arrivals or the home herd, these unvaccinated cattle were not protected from the major viral diseases. Both Bovine Respiratory Syncytial Virus (BRSV) and Mannheimia haemolytica (bacteria that causes severe acute lung damage) were detected in the necropsy case.

Farm #2 purchased from a known and trusted farm but did not take an extra precaution of isolating the newly arrived bull from the resident herd. Although in this instance, the cattle on both farms had been vaccinated against the major disease players, it is important to remember that there are other known viruses and bacteria for which a vaccine is not available. Although this bull appeared healthy, he may have been “subclinical” — incubating a virus and/or bacteria that the resident cattle had not been exposed to or vaccinated against.

The COVID-19 event teaches us the importance of personal biosecurity: avoiding close contact (social distancing), washing hands often, cleaning and disinfecting surfaces, avoiding contact with sick people, and staying home if we’re sick.

In cattle health, the greatest risk is introducing new cattle and traffic between farms/operations.

It is a good time for all cattle producers to review biosecurity practices:

1. Keep a closed herd as much as possible, purchasing bulls and all replacement animals from reputable sellers.
2. Quarantine new arrivals for 21-30 days before allowing them contact with your cattle.
   1. Design the quarantine area to prevent cross-contamination between cattle.
   2. Do not share water troughs or other materials between the new animals and resident cattle during the quarantine period.
   3. Consider a separate person to care for the new arrivals. If this isn’t possible, then care for the resident animals first, then the new arrivals.
   4. Monitor the new arrivals daily for signs of disease.
3. Keep all equipment, vehicles, and clothing clean to decrease the chance of microbial contamination.
   1. Keep a record of visitors to the farm, including feed trucks.
4. Prevent manure contamination of feed and feeding equipment
   1. Use different equipment to feed and clean pens.
   2. Never step in a feed bunk!
5. Develop a routine vaccination program
   1. Work with your veterinarian to determine what is needed for herd health in your area.
   2. Keep reminders for vaccines and all preventive care in your calendar.
6. Control Diseases
   1. BVD (Bovine Viral Diarrhea): many bull sales will test the bulls for BVD Persistently Infected (PI)
   2. Johne’s Disease: purchase from a producer who has been actively (annually) testing the herd with negative test results
   3. Bovine Leukosis: purchase from a producer who has tested the herd with negative test results

It is always a good idea to treat new arrivals like they do have a contagious disease!

Isolate (quarantine) new arrivals. This not only helps prevent disease spread but also helps the cattle adapt and be less stressed and less likely to shed.

When you visit other farms or locations with cattle and other animals, be sure to clean your boots/shoes/clothes after coming home and change into farm clothes before visiting your cattle.

Remembering all of these biosecurity steps will help us achieve our goals of having healthy resident herds and successful businesses in the Carolinas.

Sources:

BQA Chapter 3 Biosecurity- https://www.bqa.org/resources/manuals

SC Ag-Watch Manual, 2017 Update

Submitted by: Patty Scharko, DVM, MPH; Extension and Field Veterinarian; Clemson University Livestock Poultry Health

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