Animal Health Matters: A spoonful of sugar for you, a clean needle for the cow
When was the last time you encountered a gristly, inedible mouthful of beef while otherwise enjoying a nice roast or steak? Chances are it was a long time ago (or maybe never, if you’re not that old).
Those unchewable chunks in a piece of otherwise tender and tasty beef were often the end result of an injection given to the animal well before it wound up on your plate: the remnants of the body’s healing process from a vaccine, antibiotic or other injection. When these liquids are injected into muscle, the body starts absorbing them into the bloodstream to do their assigned purpose. The nature of these injections also creates tissue damage, however. The architecture of the muscles is disrupted, and sometimes the substance itself is irritating and inflammatory to the tissue. If bacteria are introduced, infections and abscesses can result. This disruption and inflammation heals over time with gristly scar tissue.
This scar tissue-forming healing process is why subcutaneous (under the skin) injections are preferred over intramuscular ones, as mentioned in my most recent column. Problems under the skin have less effect on the muscle – and therefore the meat – that will end up on our plates someday.
But these problems are nowhere near as commonly encountered as they once were. One of the many projects taken on by the beef checkoff is called the National Beef Quality Audit, a periodic checkup on all things that affect quality of cattle production’s end product. Charting the prevalence of injection site lesions in beef carcasses is one aspect of the survey.
The first survey in 1991 showed that a whopping 22.5% of beef carcasses harbored injection site reactions. In 2005, this percentage dropped to 2.5%, and the most recent survey in 2016 found less than a percent of carcasses with these problems.
What happened since that 1991 survey? It’s of special interest to me, since the surveys span my beef cattle practice career. Back in my early days of veterinary practice, producers (and yes, some veterinarians) would commonly give injections in the rear hip of a calf or cow – a prime example are of the bovine body for roasts and steaks.
Enter the Beef Quality Assurance (BQA) program. It was developed to address this unacceptable rate of injection site problems. Educational efforts ensued to move injections from the hip to the neck of the animal – a part of the carcass less likely to become a prized piece of beef. Animal drug and vaccine manufacturers placed more emphasis on tissue-friendly drugs and subcutaneous administration routes.
Injection site problems have not disappeared completely. They still represent a significant cost to processors who have to trim away these affected areas. And even if they’re uncommon, that one consumer that encounters a chunk of gristle in their roast might opt for pork or turkey next time. Anyone giving injections – especially intramuscular injections – to cattle can influence whether these blemishes occur or not.
Infected injection sites are particularly problematic causes of carcass blemishes. While barnyards and cattle chutes aren’t exactly sterile locations, there are some common-sense things we can do to minimize infections. Vaccinating or treating calves with wet hides during rainy weather is a surefire way to cause infections and abscesses; putting off the job for a drier day will pay dividends. Needles should be sharp and free from burrs or bends – meaning they should be replaced often during a chute job. Animals should be well restrained to prevent unnecessary jostling during injections. One should never fill a syringe with a needle that was used on a calf – that will just introduce bacteria to the whole bottle.
When giving antibiotics, which require a larger volume of medication than do vaccines, make sure that only 5-10 cc’s are injected into one spot: too much in one location will result in excessive tissue damage and will prolong the withdrawal time.
And when considering injections, maybe the best choice is to not use one at all. While we haven’t developed water, feed or pour-on vaccines for cattle yet, those administration routes are available (and very beef-friendly) for some antibiotics and other treatments.
While there are still some improvements to gain, the reduction in injection site blemishes in beef carcasses is a great example of how a problem can be sufficiently addressed once the various segments of an industry come together to solve it.
Russ Daly, DVM, is the Extension Veterinarian at South Dakota State University. He can be reached via e-mail at firstname.lastname@example.org or at 605-688-5171.