Biosecurity on the Farm


A lot of farmers may view the recent increase in the use of the word ¡°biosecurity¡± in a lot of publications as one of those fads and $100 words.  However, biosecurity may be one of the concepts that can save you money and increase your ability to stay in business.


The word ¡°biosecurity¡± implies some reduction in risk caused by life forms.  This risk might come from such life forms as viruses, bacteria and fungi, or the risk might come from rabid raccoons or skunks, or even from coyote predation on a flock of sheep.  The security part of the word involves the management practices that each farmer uses to reduce or control the life forms that can affect the animals.  In short, how do you keep your animals healthy?  Another way of looking at biosecurity, is to consider ways of keeping disease organisms from affecting your animals, or if you have some disease, how to keep that disease in check. 


As our first example, consider some of the common diseases that can affect our livestock.  Many of the respiratory and reproductive diseases of cattle and sheep are caused by viruses (IBR, BVD, BRSV) which can be brought to the farm in a variety of ways.  Some are airborne, some can come in on the boots and clothing of visitors, but most probably arrive with animals which have been purchased.  Biosecurity would thus involve the steps you would need to take to reduce the risk of those diseases arriving, and the prevention practices to protect the animals already there. 


As our next example, consider one of the organisms that causes mastitis and is also contagious to other cows.  An organism such as Streptococcus agalactiae, commonly called Strep. ag., is one example.  These bacteria don¡¯t live in manure, water, or sawdust.  They live in the udders of cows!  When a cow from a herd of dairy cows suddenly becomes newly infected with Strep. ag. mastitis, it means that the milk from some other cow who was already infected came in contact with the teats of our newly infected cow.  That milk, with the bacteria, might have made contact as a result of milkers hands or inflations on the milking unit.  If the herd had never had this form of mastitis before, it is likely that an infected cow was brought into the herd from another farm.  In other words, you paid good money for the Strep. ag.!


Now, in both of the above examples, there are management practices that can reduce the risk of animals getting infected.  I¡¯ll outline some of the practices that apply for each example and then a group of general practices.


Example 1 - Disease entry to the farm


A. Vaccinate your animals

For most common diseases, there are vaccines that are available that will aid in the prevention of disease.  Consult your veterinarian and vaccinate according to the label.  Some vaccines require annual boosters, and in some high risk areas, many veterinarians are boostering animals every six months. Remember that most vaccines require refrigeration and have an expiration date.


B. Disease control with purchased animals

Many farms purchase breeding stock, cleanup bulls or rams or mature animals without taking the steps to control what they might be bringing in, or what they might catch from your animals.  Insist that any animal you bring to your farm have a vaccination series similar to yours, and that it be at least a month since those vaccinations.  If this is not possible, then you should have a separate facility to quarantine those animals away from your animals.


C. Control the sanitation of your visitors

On some farms, all visitors are required to wear those plastic disposable boots upon arrival.  This is a pretty good idea, particularly for those visitors who travel from farm to farm.  You should have those boots available and make your visitors wear them.  I know that this sounds tough, and you may not have the ¡°stomach¡± for it.  But, it makes sense.  Remember too, it helps keep your visitor from ¡°tracking¡± your disease to the next farm.  For example, if you help load an animal onto a trailer that contains animals from other farms, go wash your boots before going back in with your own animals.


D. Wild animal and airborne contamination

It is known that skunks, and raccoons can carry rabies.  It is also known that rats, mice and other wild animals can carry the organisms that can cause abortion, such as leptospirosis. Control the on-farm rodent populations, and again, vaccinate against those organisms that can be carried by wild animals.  Remember also that some of the airborne diseases may also affect animals right on the farm.  Older animals may pass organisms to very young animals.  Dr. D. W. Bates from the Univ. of Minnesota always used to say, ¡°keep the youngest animals upwind from the oldest animals.¡±


Example 2  - Contagious Mastitis


A. Know the mastitis history of purchased cows

Most farms that purchase cows who are already milking rarely check the history of that cow.  They should, but they don¡¯t.  Again, as with our first example, the disease history should be obtained.  With mastitis, in this case, that purchased cow should be sampled from each quarter and the milk should be cultured by the Mastitis Laboratory to see what she has.  Until you know what organisms, if any, that she has, that animal should be milked last so that the milker¡¯s hands and the equipment does not come in contact with the udders of other cows.


B. Keeping the disease from spreading

If you know that a cow has Strep. ag. mastitis, then you should treat the animal with antibiotic and reculture.  If treatment does not work, then the cow should be culled.  If that is not your choice, then at least milk those cows last in line.


C. Sanitation during milking

For contagious mastitis, it is important to recognize that the milk that you might strip out of the udder can have the bacteria in it.  Any cracks in milker¡¯s hands can trap bacteria and be passed on to the next cow.  Milker¡¯s hands should be washed and dried between cows if you have contagious mastitis.  Rubber gloves can be washed a lot cleaner than milker¡¯s hands.  It is something to consider.  Teat dipping was designed to control the so-called environmental forms of mastitis, and has little effect on the contagious forms.


General Biosecurity Measures

In summary, consider the following in establishing a good biosecurity program.  Remember that farms are food producing units, and that we have a responsibility to maintain high quality and safe food products.


A. Understand the diseases that can affect your animals and how best to prevent them by vaccination and sanitation.


B. Control the diseases you might bring to the farm by knowing the disease history of any animal you purchase.


C. Control the spread of disease on the farm by sanitation and vaccination.


D. Control the possibility of disease entry to your farm by insisting upon proper footwear for visitors.


E. Keep the food products leaving your farm safe and healthy through proper care of your animals and the raw food product that you sell.    


William E. Graves

Dept. of Veterinary and Animal Sciences

University of Massachusetts Amherst

Crops, Dairy, Livestock News. Vol. 3:2, Winter 1998-99

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