Friday, January 31, 2014
Balancing cure rate, economics, welfare and antibiotic resistance
At the moment I am on my way back from the NMC (National Mastitis Council) annual meeting, that was held in Fort Worth, TX. At this meeting I was invited to give a talk on this topic, in the session: “Analytical approaches to managing mastitis”, a session preceding the session entitled “Treatment and non-treatment approaches in tackling mastitis”.
The title of my presentation was: "Treating mastitis: Balancing cure, welfare, money and resistance". As always I have made my presentation available through slideshare. In the presentation I show some results that I found in literature, mainly on economic balancing (optimization), but given the session I had to talk in, my presentation also explained how you can make economic calculations on different treatment options and how you can optimize treatments (for instance by the use of linear programming).
But the whole thing of balancing might be novel of thinking and therefore a good topic for an entry on this blog. It has been too long since my previous entry anyhow.
Naturally, veterinarians and many other animal health professionals are aiming at the highest cure rate. We strive for healthy animals. The situation with regard to mastitis is no exception on this rule: Let’s treat an animal with the best possible treatment. That is good for the health and welfare of a cow. In fact there is not much balancing between cure rate and welfare, at least not in my opinion. I would argue that a better cure rates is approximately equal to better welfare. But what about economics and antibiotic resistance? Let me give an example of an e-mail debate I had last year about selective dry cow therapy.
It started with a question of a representative of a pharmaceutical company to a number of mastitis experts (I was among that group). The question was about proper criteria to select cows for dry cow therapy. There was a quick answer from a renowned mastitis specialist that it was silly to do this, because it is proven that the risk of clinical mastitis is higher when dry cow therapy is skipped. And this specialist is right. For whatever group of cows, in whatever situation (also the situation in many Nordic countries where hygiene for dry cows is very good), when dry cow therapy is omitted there is a (sometimes slightly) higher risk of mastitis in the next lactation. So to minimize the risk of clinical (and subclinical) mastitis in the first 100 days after calving, you should use blanket dry cow therapy.
Now, when you toss economics in the equation, things might change a bit. The costs of treating each cow with antibiotics at drying off to prevent a small proportion of cows to get clinical mastitis, is not cost efficient. So, depending on the risk for a farm system or a certain group of cows within a farm system, selective dry cow therapy might be economically profitable. And indeed, there needs to be a balance between the welfare (cure rate) and the economics.
If we take things a step further and toss the use of antibiotics into account, things differ again. In the Netherlands, we want to reduce the use of antibiotics and omit the preventive use antibiotics in animals. Than we might set for ourselves a limit in the amount of antibiotics that are used (expressed in “daily doses”). So when we limit ourselves in the use of antibiotics, it might go at the costs of the welfare of cows (more mastitis cases during lactation) and the economic results of the farm (higher costs for mastitis associated with the dry period). Linear programming might help us finding the economic optimum given a threshold of antibiotics to be used. We can also set a welfare threshold.
Using these type of methods, we can provide decision makers with the consequences of their decisions, we can provide tools. But it is in the end up to decision makers, farmers, regulatory bodies and governments how they balance animal welfare, economics and use of antibiotics .