As dairy herd sizes increase, one way many farms have helped manage their costs is to do more routine veterinary work themselves such as vaccinations and treatment of common ailments; or they might be using rBST on selected cows.
Under the direction of a proper veterinary/client/patient relationship (commonly referred to as a VCPR) that establishes proper products and uses, this can be effective and cost efficient. This practice also exposes workers to an additional safety hazard, though accidental needle sticks.
Research has found that over 80 percent of livestock farm workers and 73 percent of swine veterinarians have at some time accidentally stuck themselves with a needle.
While dairy cattle may be a bit easier to control and work with than hogs, the hazard is there just the same. I remember a personal incident very well. Once, while vaccinating baby pigs during my own farming career, I accidentally vaccinated myself for erysipelas when a baby pig suddenly jerked its head over just as I was about to inject vaccine into its neck.
The Upper Midwest Agricultural Safety and Health Center (UMASH) at the University of Minnesota has developed a pair of factsheets that point out the hazards and suggestions for preventing this rather common injury. Most of the time, these needlesticks are harmless other than perhaps a bit of irritation, but there are some injectables that can cause severe reactions or even death. The most common injuries are skin infections, allergic reactions to the carrier, and occasionally deep tissue wounds requiring surgery.
Think about it for a moment.
If an animal has an allergic reaction, or the needle happens to carry bacteria into an animal injection site, what normally happens? The site swells up and might even develop an abscess that needs to be lanced to relieve pressure. Because an animal's skin is generally loose on top of the muscle tissue, that can be unsightly and damaging to tissue but not usually dangerous to the animal.
Human skin, however, it tightly attached to the muscle, though, so that same reaction process in the human body can create a major blood flow restriction or severe swelling that can only be relieved by creating an open wound subject to further infection and a long healing process.
Less common, but very serious, injuries can include miscarriages by pregnant women exposed to hormones, drowsiness or unconsciousness from sedatives, cardiac arrest from products like Micotil/tilmicosin, systemic infections from vaccines, and antibiotic reactions.