The author is a partner in the Maria Stein Animal Clinic, Maria Stein, Ohio.Drug abuse means to use a drug incorrectly or excessively. I’ve been pondering this article topic for years, and now many veterinarians have asked me to write it. Their frustration and mine is that some drug uses have the potential to damage our industry, and there are other drug uses that could be better directed.
Who determines the right use? Certainly the label indications are the correct use.
Not every situation that warrants treatment is covered by an approved drug. We need to be careful as we go down the path of using drugs beyond their label use. We must be sure their mechanism matches our expectations and that there are limited unintended consequences.
We journey into the land of those unintended consequences when we routinely ask, “What else can I give?” and presume it can’t hurt. Many drugs have consequences beyond the obvious and well known.
Some wild uses have come from veterinarians. I apologize if I offend you, but it may be time to reconsider your off-label recommendations. There is a developing consensus in treatment protocols that is largely influenced by veterinarian interaction on the American Association of Bovine Practitioners (AABP) list serve. Many of the drugs discussed have a more clear understanding of action than they did years ago.
I refer to a quote Steve Weisbrode, V.M.D., gave us just before veterinary school graduation. He said, “You have been given a tremendous education with a large amount of knowledge. Twenty percent of that knowledge is right and always will be right, and 20% is wrong and always will be wrong. The remaining 60% will change over the course of your career. Your challenge is to continue your education and engagement such that you are aware of which category a piece of knowledge is in and change when needed.”
Most practitioners do this well. The others put us all in jeopardy.
Preserve for human use
First and foremost, the mandate is to do no harm. This type of abuse is risked when withholds and restrictions are ignored and saving the animal is placed before maintaining the industry. I’ve lived through the times when gentamicin, florfenicol, enrofloxacin, spectinomycin, and tilmicosin were all used to treat various conditions in lactating cows. The time has passed long ago for this to be anywhere close to okay. The risk to individual humans and our market is too great to consider such use. If you are doing this, stop! If you don’t stop, you deserve the penalties that should come when you are caught.
We have also been asked to not use ceftiofurs in an extra-label manner. This is due to preserving efficacy of this class of drugs for human diseases. Problematic is those who were once advised that Excede could be given anywhere other than in the base of the ear. That’s where it goes or you don’t get to use it.
More harm than good
There are a few drugs that are used in ways their mechanisms of action do not support. Vitamin K is appropriately used when factors in the clotting cascade have been blocked, especially in the case of coumarin created by moldy sweet clover. This situation is very rare on modern dairies.
Injections with vitamin K may be common because they have always been given whenever there is bleeding. There may be little harm in that, but more than once, I have seen caregivers not address the bleeding because they had expectations of vitamin K that weren’t possible. Vitamin K cannot stop bleeding when a vessel has been severed. The vessel needs to be clamped or ligated.
Giving intravenous (IV) calcium to standing cows can do more harm than good. There was a time this was standard practice in well-managed herds, but we now have great oral products that do a better job of improving calcium status. IV drugs are rescue drugs, and standing cows rarely need to be rescued.
Normal blood calcium is around 10 milligrams per deciliter (mg/dL). IV calcium can raise this number to near 20 mg/dL. Homeostatic mechanisms then kick in to lower the calcium level, but it overshoots the normal and settles to around 8 mg/dL for a day or two. At this level, immune function is impaired by reducing the margination and capacitation of white blood cells.
Giving IV glucose to cows that are only mildly ketotic depresses appetite and gastrointestinal (GI) motility. We want appetite and GI motility for cows to eat their way out of ketosis. IV drugs are rescue drugs, and severely ketotic cows that need to be rescued show better responses when they are IV’d once with a glucose product followed by oral glycol or glycerine. Mildly ketotic cows usually respond better to the oral products because they don’t have high levels of glucose telling the satiety center of the brain that they are not hungry.
I see herdsmen use hypertonic saline very causally. That product is designed to be used aggressively to move fluids from the extracellular space to the vascular space when a cow is in shock. That means giving 2 liters IV in a dehydrated adult cow as fast as you can. The depleted extracellular space then needs to be replenished. I always do this with oral fluids. Some expect the cow to respond by drinking adequate fluids. Almost none do. They end up more dehydrated than if they had not received hypertonic saline at all.
Producers have told me that they have been advised to give all indigestion cows magnesium sulfate (pink) boluses. Those pink pills are a very strong base. They can move an acidotic rumen to a more neutral environment. Off-feed cows have a reduced fermenting mass in their rumen that creates acid. So, they are no longer acidotic. Giving them pink pills creates a more basic environment, reducing the activity of the fiber digesting organisms we are trying to promote. Probiotics, prebiotics, and yeast might be better choices to encourage appetite.
Product and cost savings
Dexamethasone is the perfect drug. Inexpensive and with no withholds, it makes cows feel better temporarily. The only downside is abortions. But wait. This drug is used to create immunosuppression in experiments. It does a great job of that. Is that what you want in your recently fresh cow? You need the cow’s immune system working full steam. Its use in ketosis cases has limited results compared to energy supplementation.
For inflammation, flunixin might be a better choice. Nerve injury or diphtheria cases may have a special place for dexamethasone, but this drug should be used sparingly. That’s not because it might help, but because we know it can hurt.
It might be time to evaluate your treatments with your veterinarian to be sure you are not a drug abuser. Your cattle will respond better and there are probably some savings involved.