Is the Old Refrigerator at Your Cowpens or Barn Reducing the Effectiveness of Your Vaccines?

Gant Mourer, Beef Value Enhancement Specialist Oklahoma State University

Respiratory disease in cattle, also known as BRD, shipping fever or pneumonia may cost the U.S. cattle industry over $2 billion annually (Powell 2013). Management techniques can offset much of this cost, and having a good vaccination program can maintain the health of a calf all the way through the production system. A vaccine can cost over $3.00 a head, and if not stored properly that vaccine can be rendered ineffective. Producers cannot afford to overlook the importance of how they store vaccine and handle it prior to injection.

Biological products should be stored under refrigeration at 35 to 45⁰F, unless the nature of the product makes storing at a different temperature advisable (APHIS 2007). If vaccines are not stored within this temperature range, efficacy to the calf can and will be reduced. Killed vaccines are especially susceptible to freezing temperatures. Freezing a killed vaccine will alter the adjuvant or delivery system of a killed vaccine. This, in turn, negatively affects the immune response to the antigen in the vaccine. Modified live virus (MLV) vaccines are more stable, but can be in-activated if they are repeatedly cycled above or below the required temperature range (Gunn et al, 2013). Also, once activated by mixing, MLV’s effective life is reduced to 1-2 hours, and need to be maintained at the 35⁰ to 45⁰ F. This can be accomplished by only mixing the doses that you will use at that time, and the use of a cooler to maintain temperature while working cattle.

Researchers from the University of Arkansas and Idaho analyzed the consistency of temperatures for different types, ages and locations of refrigerators over a 48 hour period. They found that only 26.7% and 34.0% of refrigerators were within the acceptable temperature limit 95% of the time, respectfully. Refrigerator location can also effect temperature. Refrigerators located in barns (35.6 ⁰F) were colder than in mud rooms (41.72 ⁰F) and kitchens (40.82 ⁰F). (Troxel and Barham 2009). Temperature within a 24 hour period can also be highly variable for individual refrigerators. Troxel and Barham (2009) demonstrated some refrigerators may take up to 8 hours to cool down to the 45⁰F required, or temperature can drop below freezing and range from 28.4⁰F to 44.6⁰F, while others will remain too cold varying from 24.8⁰F to 35.6⁰F over that period of time.

Producers need to be aware of these variations in temperature so they are able to adjust refrigerator temperature as needed. Thermostats can also be very variable from unit to unit.  It is very important to keep a thermometer inside your refrigerator to monitor temperature and to make adjustments as needed. Simple indoor-outdoor thermometers work well to achieve this goal. The outdoor unit can be placed in the refrigerator while the LCD display can be hung with a magnet on the door. This allows temperature to be monitored without opening the door, and many models will record the high and the low temperature in a 24 hour period, so producers can adjust accordingly.

How a producer handles vaccine outside of the refrigerator is important as well. Coolers can easily be modified for syringes and are important to maintaining vaccine efficiency chute side. Using a 1 ½’ PVC pipe or sink tail piece purchased at any hardware store and a 1 ½’ hole saw, inserts can placed through the cooler and work well to keep syringes cool and out of light while in use. Either ice or freezer packs can be used as a coolant to maintain temperature for several hours depending on outside ambient temperatures. Make sure that enough coolant is used to maintain temperature while working cattle.  Extra ice may be needed if working cattle all day or on hot days. It may also take up to an hour for the cooler to reach the needed 45⁰F, so producers may need to plan ahead prior to processing cattle.  Detailed instruction on the construction of a chute side vaccine cooler is available in Oklahoma State University Fact Sheet ANSI-3300 “ Chute Side Vaccine Cooler”.

These are a few simple suggestions that can help ranchers get the full value of the vaccine that they purchase. More importantly, positively affect the health of their herd, decrease sickness, and increase profit.