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Needle-Free Injection Put To The Test

A research team at the University of Manitoba is investigating the potential of using a needle-free injection device (NFID) for delivering vaccines to beef cattle.

NFIDs use pressure to drive the vaccine though the hide into subcutaneous or muscle tissue. Mechanical pressure on the nozzle triggers the injection as it touches the skin, explains Michel Rey, a masters student on the project supervised by Dr. Kim Ominski.

The idea of using needle-free injections to vaccinate people originated in the 1940s, however, only in the most recent decade has the technology been revived and improved upon for use in human and animal health. Most of the research and uptake has been in the swine industry in the U.S. and Canada, while most of what little research has been done with cattle has been carried out at Kansas State University with dairy cattle housed indoors.

We know from previous studies that needle-free injections have many advantages, so our research will focus on investigating whether using a NFID to administer vaccines will generate an immune response capable of protecting the calves from disease and whether this is a piece of equipment that can be used year-round for delivering all types of vaccines or whether it is best suited for specific vaccine products administered under certain conditions, Rey explains.

The Manitoba study is looking at whether antibody response to two types of vaccines delivered with a NFID differs from that when the vaccines are administered by the conventional needle-and-syringe method. The second segment of the study will evaluate how the NFID stands up to use in cold weather as well as whether conditions such as the increase in hair coat and hide thickness will affect penetration of the vaccine.

Eighty spring-born calves were divided into three groups with 10 in a control group and two treatment groups of 35 calves each. One group was vaccinated with a NFID and the other with needle injections. The calves were 60 days of age at the time of the initial vaccination and boosted according to vaccine label directions.

Two vaccines commonly used in beef operations were administered on opposite sides of the neck: a clostridial, which is a killed vaccine that protects against certain bacterial infections such as blackleg; and a five-way respiratory vaccine, which is a modified-live product that also protects against bovine viral diarrhea (BVD). All calves were screened for BVD prior to the start of the study to ensure that none were persistently infected. Blood samples to be analyzed for antibody titres against blackleg and BVD are to be taken throughout the study.

This segment of the trial wraps up with final blood samples drawn when the calves are 201 days old and the trial will be duplicated with fall-born calves. Rey expects the results to be available sometime next summer.

His review of published studies reveals that use of a NFID potentially has more advantages than disadvantages when compared with needle injections. The most obvious and most important is that the NFID does away with the needle, thus eliminating the possibility for broken needles to end up in meat cuts, the need for used-needle disposal and accidental needle sticks to people. Some studies cite a reduction in disease transmission and others suggest that use of a NFID reduces the time it takes for producers to vaccinate their cattle. Needle-free and needle systems appear to be on equal footing as far as triggering an immune response. There have been mixed findings on injection site lesions in swine, however, there has been little to no research investigating site lesions in cattle vaccinated with a NFID. Likewise, there is no evidence to suggest that needle-free injections are less painful than those delivered with needles, primarily because there has been no research with livestock to measure pain and stress levels associated with either method. People participating in a study reported higher levels of pain when vaccinated with a NFID.

Rey, who hails from a cow-calf operation, says as far as his personal observations go, he didn t notice any real difference in animal behaviour between calves vaccinated by NFID and those vaccinated using a needle and syringe. The sound of the pressure when the NFID triggered didn t seem to bother the calves.

The straight-out disadvantage is the cost of NFIDs, which currently run in the neigbourhood of $2,500 to $5,000. They are more complex than a needle-and-syringe system, therefore, training to perform the injections and maintain the equipment might be an issue.

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