Good Biosecurity Didn’t Start With HPAI

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Fred M. Hall
Dairy Specialist
Iowa State University Extension & Outreach


With everyone’s focus on the implications on HPAI in the dairy industry, let’s remember that good biosecurity and best management practices have been the mainstay of a healthy dairy herd since we learned that illness and disease are transmitted by bacteria and viruses.

Biosecurity always starts with sanitation on the farm. Cleaning and disinfecting are imperative to maintain the wellbeing and health of high producing animals. Let’s consider four important hygiene areas around the dairy: Housing area, milking area, plus animal and people cleanliness.

Sanitation in the housing area is the reduction of bacteria in the immediate surroundings and reduces the opportunity for bacteria to gain access to the animal and cause diseases. While swine and poultry systems utilize the “all in, all out” stocking policy, where the terminal cleaning and disinfection of facilities is possible, dairy producers rarely have that asset to prevent disease. After daily maintenance, at some point all bedding and equipment must be removed before soaking and cleaning. The nature of the surfaces will influence the efficacy of the disinfection. Rough, porous surfaces are harder to disinfect than smooth surfaces. Porous surfaces are also harder to clean than smooth surfaces. Porous surfaces will therefore have heavier soil loads after cleaning, which further increases the difficulty of disinfection. A broad-spectrum disinfectant with penetration enhancers should be used.

It should be obvious that where the animals are milked carries a high risk of vectoring disease as this is where there is direct contact. The milking parlor or stall should be disinfected twice daily. Surfaces should be cleaned regularly to avoid multiplication of pathogens on exposed surfaces. As the milking machine is cleaned every day, it should be the same for the milking parlor itself. After each milking, rinse all surfaces with clean lukewarm (100-110°F) water to remove milk solids. When done properly, this rinse removes more than 70 percent of the soil load. After rinsing, use a chlorinated alkaline detergent solution in either liquid or powdered form to wash the equipment. Add your detergent to the wash water according to manufacturer specifications. Soak all parts of the milking machine in the detergent/water solution at a temperature of 120- 135 ºF for at least 5 minutes before scrubbing all surfaces, inside and out. Finally, rinse the whole milking equipment with cold acidified water for 2-3 minutes and drain.

Prior to the next milking, soak the milking equipment in a chlorine-based sanitizer in clean lukewarm water (100-110°F) solution and allow to drain dry.

It is always more enjoyable to work with clean animals, that where a curry comb and a brush come in handy, but I wan to focus on teat hygiene considering two of the most dangerous periods when animals are more vulnerable to mastitis causing agents are during milking and immediately after milking.

Pre-milking preparation with teat disinfection is a must: a detergent and disinfecting solution can be sprayed on the teats or applied with a dip cup as a liquid or foam, then the teats are dried with a single use paper towel or reusable cloth towel which are laundered between uses. Dip cups or spray bottles should be cleaned and disinfected after each milking.  Reusable cloth towels should be laundered with hot water, have chlorine added to the washing machine and dried completely to reduce the bacterial load on the towels. 

After milking the risk of contamination is high because the teat sphincter is open and can stay open for two hours or more after milking. The Food and Agriculture Organization (FAO) highlights the importance of the post-milking teat disinfection because it kills possible germs that get on the skin during the milking process (contagious pathogens which can result in mastitis). It is also important to cover the period between milkings. As teat dips are applied after milking on the skin of the animal, it is critical to use well tolerated formulations which will not cause dryness and cracking of the teat skin.

The milker and cattle handler must wear clean clothing during milking and when handling milk. Milkers must wash their hands and forearms thoroughly before milking. Wearing gloves is recommended and they must be kept clean during milking and milk handling.

Bacteria are everywhere: in soil, in water, on animals and on humans. The purpose of washing and disinfection is to decrease infection pressure and thus decrease disease prevalence.

For more information, contact the ISU Extension and Outreach Dairy Specialist in your area: in Northwest Iowa, Fred M. Hall, 712-737-4230 or; in Northeast Iowa, Jennifer Bentley, 563-382-2949 or; in East Central Iowa, Larry Tranel, 563-583-6496 or; in Ames, Dr. Gail Carpenter, 515-294-9085 or

Date of Publication: 
May, 2024