The recent hardships faced by European producers due to the spread of foot and mouth disease in 2001 and 2007 are prime examples of the importance of biosecurity for dairy farms.

The U.S. has not had foot and mouth disease since 1929 and an outbreak would devastate the livestock industry. There are other infectious diseases prevalent in the U.S. that are causing financial losses to dairies. This includes Johne’s Disease, a disease that progresses slowly and causes cows to lose body condition due to long-lasting diarrhea and weight loss. Research has shown that a cow with Johne’s Disease can cost a dairy over $200/year in reduced production and premature culling.

The prevention of diseases on a dairy is also usually less expensive than treatment. Initiating biosecurity plans on dairies has the potential to avoid the introduction of infectious diseases in a dairy herd. A biosecurity plan also reduces the spreading of clinical and subclinical diseases already present in the herd. A typical biosecurity plan should address the following issues:

• Vaccinate against disease, if a vaccine is available. Work closely with your veterinarian to establish an appropriate vaccination protocol and adhere to it. Almost half the producers do not adequately follow the vaccination routine that they have established.

• Provide adequate amount of colostrum to newborn calves. Avoid mixing colostrum from different cows to reduce the contamination risk of calves.

• Do not feed unpasteurized milk from sick cows to calves.

• Clean equipment used for non-feed purposes (loaders, shovels, etc.) prior to using for feeding. If possible, avoid using feed equipment for manure handling.

• Avoid manure contamination when pushing up feed.

• Monitor feeds for sign of mold contamination.

• Avoid stepping in the feed bunk and contaminating feed. This is very important in reducing the spreading of infectious diseases and microorganisms that incubate in the manure and that could be transmitted to healthy animals through the mouth.

• Monitor who comes onto the dairy. Utilizing a log form could be helpful in tracking down visitors. Clean and sanitize boots, equipment, clothes and hands of people moving between different facilities.

• Monitor what comes onto the dairy.

• Restrict animal access to surface water such as creeks, irrigation ditches and standing water. Surface water could be a harbor to different infectious diseases.

• Necropsy animals away from other animals, food commodities and employees. Perform the necropsy on a concrete pad that could be easily disinfected. If you do not have access to a concrete pad, use a dirt area that is exposed to sunlight for a long period of time each day to help kill the pathogens. If possible, put a fence to keep out wildlife that could serve as a carrier for the disease.

lways wear adequate clothing (coverall, gloves, boots, etc.) and use good hygiene practices when performing a necropsy. Some diseases can spread from animals to humans. Remember to clean your hands, clothing and tools before getting in contact with other animals or humans (including your family).

• Provide an easy access for rendering trucks so they don’t have to drive through pens or feed areas. Remember that some rendering companies use the same trucks to pick up animals from different dairies.

• Maintain a closed herd if possible.

• Deal with source herds and sellers that could provide pertinent history information of their herd as well as for individual cows that are purchased. It is important to know the risk for a disease before bringing in these animals so you can plan accordingly.

• Develop adequate treatment and observation protocols that allow early detection of infectious diseases before they spread and cause further damage.

• Minimize contacts with other species of animals. Pets, rodents, birds and wildlife can also be carriers of diseases.

• Keep adult manure away from calves and heifers.

• The addition of animals from external sources usually increases the risk for infectious diseases transmission. This is why it is important to establish a quarantine program when buying animals from other owners. A quarantine program would be effective in controlling infectious diseases that are characterized by a short incubation period. It will help identify animals that carry an infectious disease but that are not showing any symptoms of the disease at the time of the purchase. Quarantine is complicated for lactating cows because most dairies use the same milking parlor to milk the herd and quarantined cows, which could make the quarantine program less effective.

uarantine usually lasts 21 to 30 days and would not be effective against long incubation diseases like Johne’s or diseases that can remain at a subclinical level for a very long period of time. This is why other methods of biosecurity should also be implemented. It is also important to ensure that workers minimize movement between quarantined and resident animals to avoid contamination.

• Test lactating cows for Staphylococcus aureus, Streptococcus agalactiae, and Mycoplasma spp prior to purchasing them. Bulk tank cultures would provide valuable information on whether Streptococcus agalactiae and Mycoplasma spp are present in the herd because cows infected with them shed enough microorganisms that the bulk tank culture would come up positive. The case of Staphylococcus aureus is different because it could be shed in low numbers and intermittently.

hree serial individual milk samples need to be tested in order for the buyer to be 95% sure that the purchased cow is negative. The herd should be investigated before dry cows are purchased.

• Test purchased animals for bovine virus diarrhea (BVD) and bovine leukosis virus (BLV). These diseases can be spread by animals that look completely healthy but can be carriers of the virus.

• Inspect purchased cattle for signs of papillomatous digital dermatitis (hairy heel warts). Several dairies have reported an increase in the incident of hairy heel warts when new animals were purchased.  EL

Dr. Mireille Chahine
University of Idaho, Extension Dairy Specialist
Mireille can be reached at This e-mail address is being protected from spambots. You need JavaScript enabled to view it