Dry cow therapy

Starting a blog is one thing, maintaining it is yet another thing. The waiting time on airports when travelling is then an excellent reason to write another item for a blog. Many times the travel is done around interesting meetings in which some inspiration for a blog entry is fond. Friday I was at the DACH tagung which was held at the University of Zurich. The DACH tagung is a symposium for German language veterinary epidemiologists and the theme of this year was Tiergesundheit und Ökonomie. I had the honour to be the closing keynote speaker and was asked to give a presentation on economic analysis for different levelsof decision making. As always you can find the presentation at slideshare. Besides a classification of different types of animal diseases, levels of decision making and the decision makers involved I presented a few examples. One example was on dry cow therapy. This is an intervention aimed at a typical production disease and the, already 20 year old discussion on selective vs blanket dry cow therapy. We did publish a paper in 2007 and that was used as example. In another paper, published a little earlier we concluded the same. Note that the methods used in both papers differed (Monte Carlo simulation modelling and decision tree analysis), showing once more that there are more methods possible to tackle the same problem.

The papers showed that, on average, selective dry cow therapy is the cheapest option at the herd level, but a farmer does accept more clinical mastitis when applying selective dry cow therapy.  However, currently there is regained interest in dry cow therapy because of the discussion on the (preventive) use of antibiotics. Dutch dairy farmers have to reduce the use of antibiotics and drying-off antibiotics make up quite a large proportion of the antibiotic use. The question is then how to optimally use the limited amount of antibiotics a farmer may use. That is a typical optimization model and a student (Luuk Maas) dedicated his MSc thesis to this problem. He linked his linear programming model to data from a large trial of the AnimalHealth Service in Deventer.

The basic background of this work was that cows with an increased SCC before drying off (primiparous cows > 150.000 cells/ml and multiparous cows > 250.000 cells/ml) will be dried off with antibiotics. For the other cows you want to think about the most optimal level of use of antibiotics. It did show that it was most efficient to not treat all cows with antibiotics, even if there was no constraint (something we knew already), but Luuk also showed that when there is a reduction in the use of antibiotics of more than 35 %, there will be costs involved for the farmer. This limit is dependent on the farm.

This type of knowledge can be used when further setting thresholds for responsible use of antibiotics in dairy cattle. Yes: economics are important to support decisions. Moreover, decisions regarding production diseases are not alone a matter of the farmer. Since society and dairy processors are more and more interested  in production diseases, they also should take notice of the potential that animal health economics can offer them.

to the Netherlands. This trip was a bit of work and a bit of a holiday. Our son Erwin just did his high school exams (and he passed) and that was a good reason to combine an invitation to present at the Livestock Health and Production Group (LHPG) of the South African Veterinary Association (SAVA) with a bit of holiday together with Erwin. The meeting was very nicely organized, with good food, interesting people and a great place to keep it: Skukuza, which is the main camp of the Kruger Park. Having a meeting in Skukuza was something that had to be combined with a holiday.

This is written on my way back from Cape Town

 We did quite some gaming and saw the big five and a lot of other interesting animals. Thanks to Willem and Madaleen Schultheis, who were so friendly that we could use their car during the conference!! Some foto’s are attached.

But I do not write this blog to share holiday pictures. It is about management of animal health and I did give a number of presentations at the conference. The first was a generic presentation on new developments in the Dutch dairy industry that I thought are interesting for veterinarians in general: automation, abolishment of the quota system and the reduction in the use of antibiotics.

The second was on reproduction, where I presented quite some of the PhD work of Chaidate Inchaisri (I have written before about that work earlier) and some new material of Niels Rutten, who is currently doing a PhD. The third presentation was to replace somebody who unfortunately could not attend the meeting and the topic he was to present about was economics of mastitis, that was something I could do quite quickly, since I have a lot of material about mastitis readily available. In fact it was a presentation I gave before in Spain

The fourthpresentation was about Q fever. The organization asked me to present something on the Dutch goad and/or sheep sector. Luckily I was, together with Mirjam Nielen, one of the advisors of Maaike Gonggrijp, who did her MSc thesis on a quantified value chain analysis on the Q fever outbreak in the Netherlands in 2007-2009.

The final presentation was scheduled at 8.00 AM, after the night of the gala dinner and there was some good South African wine on that gala dinner. To my great surprise the room was well filled. My compliments for the discipline of the audience!! The presentation was an overview of the work ofMarjolein Derks, who will soon defend her thesis on Veterinary Herd Health and Management Programs (VHHM) in the Netherlands. In my opinion, these programs are of growing importance to the dairy industry. There is more and more attention of society for healthy animals and that in combination with a reduction in the use of antibiotics calls for more efforts in disease prevention. Recently Marjolein got two papers published in the Journal of Dairy Science. The first was a description of the participation of farmers in Veterinary Herd Health and Management Programs, where she related this participation with farmer characteristics, to see whether it is a specific part of the farmers that are participating in VHHM.  The most carried out activities in VHHM were (still) fertility checks and advice about fertility. The least carried out was advice on claw health and housing. Especially those farmers that use information and trust information were found to participate more often in VHHM. In the second paper, the information on participation in VHHM was related to the data of CRV (the work was financed by CRV, for which I gratefully want to acknowledge them!!).  

Farmers who participated in VHHM produced 336 kg of milk/cow per year more and their average milk somatic cell count (SCC) was 8,340 cells/mL lower than farmers who did not participate in VHHM. Participating herds, however, had an older age at first calving (+12 d), a lower 56-d nonreturn rate percentage (−3.34%), and a higher number of inseminations per cow (+0.09 inseminations). They also had more cows culled per year (+1.05%), and a lower age at culling (−70 d). A distinction was made in the level of participation. Participants in the most-extended form of VHHM (level 3) had a lower SCC (−19,800 cells/mL), fewer cows with high SCC (−1.70%), fewer cows with new high SCC (−0.47%), a shorter calving interval (−6.01 d), and fewer inseminations per heifer (−0.07 inseminations) than participants in the least extended form of VHHM (level 1). Level 3 participants, however, also had more cows culled per year (+1.74%) and a lower age at culling (−103 d).

So from these data, it seems that VHHM is associated with, very important, a better milk production level and udder health . Reproductive performance is not necessarily better and there is some more culling. The questions is now how these variables can be weighed (economically) against eachother. We have carried out some economic analyses. These are shortly summarized in the presentation and papers on these analyses are out there somewhere, waiting to be published (the MSc work of Isioma Ifende is recently accepted for publication) and hopefully accepted. So you will hear more about this topic.

Economics of veterinary herd health and management programs

In 2012, the World Buiatrics Conference was held in Lisbon, Portugal. As you might know from one of my previous posts, I was there as keynote speaker on the economics of production diseases. During these type of conferences, main sponsors are often allowed to organize a mini-session on a topic they want. The contents are the responsibility of the sponsor and not of the scientific committee of the conferen. So the three main sponsors of this conference (Pfizer; now Zoetis, Hipra and MSD) had all three a mini conference. During the Pfizer/Zoetis minisymposium, Miel Hostens and Bonny van Ranst (Ghent University) gave a presentation on The future of cattle veterinary medicine: a challenge or an opportunity. Their message was clear: the vet is the most suitable person to give advice to farmers. And many of us agree with that statement.

So there lies an enormous opportunity for veterinarians and these opportunities go through Veterinary Herd Health and Management (VHHM) programs. Hostens and van Ranst presented an interesting tool they developed that can be used in veterinary herd health and management programs. The tool is web-based and can be used this type of work, to analyse data and have these analyses available through a website: www.dairydatawarehouse.com.

In their lyrical presentation about the benefits of VHHM, there was a little dissonant. Reference was made to a discussion on Veeteeltforum (an internet forum connected to the Trade journal Veeteelt in which I publish quite a lot) about the economic value VHHM. The topic was based on an interview that I gave, together with Sake Kooistra of Alfa Accountants on advisory services to dairy farmers. 

Conclusions of an MSc thesis study, using accounting data of Alfa Accountants, was that the economic results of farms with VHHM are the same than on farms without VHHM. Farms with VHHM do have better milk production and better udder health. But they also have higher veterinary costs. And although in theory the advantages should more than outweigh the additional costs of the VHHM, in these data it did not show. The economic results of the farms in a VHHM program are equal to the farms without a VHHM program. Interestingly, the farmers’ trade journals all had very negative interpretations of this news. Becasue of these negative headings, Miel Hostens and Bonny van Ranst reacted also negatively on this research, as if we should not publish it. And yes, if you are advocating VHHM programs it is disappointing that VHHM does currently not lead to better economic results (at least not in the Netherlands). At the moment we are analyzing these data more thoroughly, so you will hear more about them in the near future.

 In my opinion, however, we should look at ourselves. How good are veterinarians in VHHM. They are good in the routine things, pregnancy checks, treatment protocols etc. but how good are they really in advising? Their knowledge is superb, no doubt about it. Moreover, in my opinion they often see the areas of the farmer’s health management that need to be improved but are they able to get that message to their farmers?

An interesting study of one of my PhD students, Marjolein Derks, revealed that the objectives of the farmer often deviate from the objectives that the vet thinks the farmer has (oops), that advisory talks are not really open (no or hardly space for questions) and that the consulting technique is quite bad. The scientific paper on this is recently published in The Veterinary Journal.

Now let’s combine the these two issues. There is a huge potential of VHHM. Obviously this potential is not utilized in practice. Let’s work on that utilization. Vets: learn how to become a successful consultant and farmers: you pay the vet, so make sure you tell the vet what you want him/her to do.

And about the economic results: my interpretation is as follows: with VHHM you have a smoother running farm, potentially higher milk production level and lower disease levels. That is good for the farmer (more fun if your farm runs smoothly) and good for the cows (better welfare because of less diseases). And all that without costing money!! That is a quite unique selling point I would say. 

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 .