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Jacob Dahl: Preparing for pig feed challenges in the EU

August 5, 2019

Using zinc in pig diets can impact crop yields and develop antibiotic resistance for some bacterial types. Are there more sustainable alternatives to antibiotic reduction?

By the year 2022, pig diets in the EU will be free of zinc oxide thanks to a recently passed ban. Jacob Dahl, chief nutritionist of Vilofoss, an international feed company, discusses the negative effects of using zinc oxide in pig feed and how the company is working to provide solutions for the future. How will pig producers face these new challenges?

The following is an edited transcript of David Butler's interview with Jacob Dahl. Click below to hear the full interview. 


David:            I'm here with Jacob Dahl, chief nutritionist at Vilofoss. Hello, Jacob.


Jacob:            Hello.


David:            How are you today?


Jacob:            I'm fine, thanks, and you?


David:            Good. Recently, in the EU, they passed a ban on using zinc oxide in pig diets, correct?


Jacob:            Correct, yes.


David:            So, tell us a little bit about how that came about and how it will affect farmers.


Jacob:            Yeah. When we're talking about the ban of zinc oxide, of course, it has to be understood as a pharmacological means, and it's been used effectively for decades to minimize the need for the use of antibiotics just after weaning in piglets. The different member states had different approaches — where Denmark has maybe been one of the countries where it was most widely used but is probably also the country with the lowest or one of the lowest consumptions of antibiotics — but now, through authorization and, then, withdrawal of this authorization, the use of zinc oxide for this purpose is coming to an end.


David:            Okay, and what's the deadline for that?


Jacob:            Well, the deadline would be in 2022 at the latest, as it's mentioned. Actually, the individual member states have the option of effectuating earlier, if they feel that it's possible.


David:            I see. Have the allowable levels been — are they reduced up to that point gradually, or is it all wide-open right now and then it just stops in 2022?


Jacob:            Well, it's been by prescription only. You can exceed the normal, what we call the nutritional levels, to a maximum of 2,500 ppm of zinc. It's been recommended to try to reduce, but there's no plan to slowly phase out the levels.


David:            You touched on something important there. Of course, zinc is a nutrient, so, of course, you have to provide that mineral. It's part of the diet anyway, so what we're really talking about here is the pharmaceutical use of zinc.


Jacob:            Exactly, yes.


David:            Why is it an issue? Why is it needed for weaning?


Jacob:            Well, zinc has been used and shown several times to have a diarrhea-reducing effect and also, somehow, a bacteria-modulating effect, thereby reducing the post-weaning diarrhea impact.


David:            Okay, and why is post-weaning diarrhea such an issue for pigs?


Jacob:            Well, first of all, it has a tremendous impact on the pig's health and survivability but also on the ability to convert feed, so it's an economic impact, but it's also a welfare impact.


David:            Yeah. I guess what I was trying to get at is: Why are the pigs very vulnerable to getting diarrhea at the time that they're weaning?


Jacob:            Well, at the time of weaning, the pigs are not used to what we would call mainly vegetable-nutrient feed, and this means that they have to convert, in a very short time, from mainly getting the nutrients out of milk into mainly vegetable-based feeds. This requires a tremendous change in the digestive system of the pigs, which challenges them, and they need to really adapt, which can be very difficult.


David:            So it's a pretty critical time on the farm for those livestock and can really affect the profitability of the farm if they don't get the pigs past that critical stage. So why is zinc being regulated? What is the downside of it?


Jacob:            Well, there are basically two downsides. There was an estimate calculated for Denmark alone where probably about 94% of the zinc added to pig feed in general is also excreted with the manure. This is way more than is then, afterwards, removed by the crops, so, over time, there will be a buildup of zinc in the soils. That's one part. Eventually, if that development continues, we could potentially reach some levels that are sort of toxic in the soil, impacting the crop yields.


                        Secondly, also, there's some evidence that the use of high levels of zinc could actually also push the development into antibiotic resistance for some bacterial types.


David:            I did not realize there was a connection between that. Do you know the mechanism for why that happens?


Jacob:            Not in detail, but I think some researchers have been connecting some genes in some bacteria that is promoted by the use of zinc oxide, and they're connected to antibiotic resistance.


David:            Okay. If you end up with too much zinc in the soil, at some point, I assume it becomes like a contaminated field, and then you can't grow food on it. Would that be accurate? Is there also a possibility that that zinc could leach into the groundwater?


Jacob:            I've not read anything in relation to that, so I couldn't say that.


David:            Okay, but it's a serious problem for our children and grandchildren if we're contaminating —


Jacob:            There was a report concerning this in Denmark a couple of years ago, and they actually estimated that most sensitive soils could be at a critical level in only 50 years if we continued.


David:            That's not really that long.


Jacob:            It’s really not.


David:            Yeah. If zinc is being used in order to reduce the amount of antibiotics, and I know that antibiotics have been regulated very heavily in Europe, what's the solution? Are there other tools that can be used to get around this problem?


Jacob:            I think most people in the business agree that there's no quick fix. We probably will not find another single product that, just putting on top, will solve this problem. The solution probably will be to utilize all the good knowledge we do have on nutrition and management and combine that into a concept that could actually handle this challenge.


David:            Go into a little more detail — what do you think the combination of factors would be?


Jacob:            Well, from the work we've been doing, one of the key factors is the reduction of protein levels, as protein is the main challenge, from a nutritional point of view, to the gut. Also, try to work with feed components that have the lowest impact on the digestive system — meaning, we need high digestibility. We need to utilize the feed, the nutrients in the feed, the best possible way — if not for economical reasons, then to minimize the level of nutrients reaching the hindgut, because then, there will only be substrate for bacteria. And if we cannot control those bacteria, we can have a negative development.


David:            Okay.


Jacob:            So, that would be the main part, and then, also, we need to work with gut development, because the pigs we wean today, we wean them fairly early, so they do have that quite immature gut. So, adding specific fiber types helps us not only to modify the microbiome but, also, to physically stimulate the development of the gut wall.


David:            So you're talking about probably a pretty customized diet, and maybe it shifts over time as the piglet grows.


Jacob:            Yep.


David:            Okay. Tell me a little bit about the Danish Pig Academy that your company is involved in.


Jacob:            It's basically something that was set up to have common training facilities for foreign farm workers in Denmark and visitors. All the Danish companies in agribusiness have joined forces to have a showroom where you can have a concentrated introduction to the products and also a common place to do trainings on different levels.


David:            Okay. Do you see any other challenges for pig producers in the EU coming down the pipe?


Jacob:            There are a lot of challenges we have. There are constant general environmental challenges but, also, welfare issues increasingly are important, and we need to address that much more in the future.


David:            What are some of the methods that farmers are taking, or that the Danish Pig Academy is proposing?


Jacob:            Well, from the welfare point of view, it's widely accepted that there should be more space for pigs. They also discuss later weaning; that's a challenge for financial reasons for the producers. Also, lowering stress in general is important. Of course, we have to also handle castration and tail dockings. Those are the two most concrete examples that are in the public opinion currently.


David:            What challenges are you seeing related to climate change and greenhouse gas regulations?


Jacob:            Well, from a carbon footprint point of view, the pigs cannot compete with poultry or maybe fish, but, luckily, they are somewhat more efficient than the ruminants — but we need to continuously improve, especially the feed conversion. The feed utilization is of importance here. Of course, in general, efficiency in pig production will lower the carbon footprint per produced kilo of meat.


David:            What are the methods that you think we should be exploring to try to get that feed efficiency higher?


Jacob:            Well, a healthy gut that is able to utilize the feed at its best is important, so anything to support the health of the piglets (would help). Also, in general, to limit health issues, because immune responses take up energy, take up nutrients that otherwise could be used for growth. So, in general, health is very important and, yeah, we need to continuously improve both the efficiency on the sow side, because that's where part of the carbon footprint comes from — so more piglets per sow reduces the imprint per pig.


David:            Sure. I'm sure we're learning more and more all the time about how complex and how important the microbiome is. What are the best ways to ensure that you have a healthy microbiome?


Jacob:            It's a very difficult topic. It's very complex, and I think there's still a lot to learn, so, from my point of view, I'm trying just to look at the pig and see, does the feces look all right? Do we have diarrhea or not? But also, trying to work with some of the mechanisms that we know influence the microbiome in a positive way, using the fibers of the prebiotics and some of the organic acids that we can add — but it's actually also some of the metabolites coming out of some of the bacteria in the microbiome.


David:            Okay. Can you tell me a little bit about your role at Vilofoss and what the company does and how you help farmers?


Jacob:            Yeah. Vilofoss, actually, you could say it's a multinational company coming out of Denmark but with activities in Germany, France, Sweden, and sales in most countries in Europe. We are active in Russia as well and do have some activities in China. Lately, we're also starting up in Spain. We have a big organization that consists of technical people in the local countries and then, based on these people, we have formed an R&D group where we work together to develop our concepts and, also, from the national point of view, try to have a common practice but also try to adapt to the local or national markets. My role is being responsible for Denmark on the pig side, both for R&D and technical support, and also as a part of the coordinators coordinating our international activities. I do support technical support to our sales force — mainly in Denmark, but also in China and Russia — and technical discussions amongst the colleagues in Europe.


David:            All right. Thank you very much, Jacob. I appreciate you spending some time with us.


Jacob:            Thank you.


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