Contents

1. Principles and Strategies for Success
   
2. Biosecurity, Pig Flow, and Introduction of Stock
   
3. Breeding Herd
   
4. Farrowing
   
5. Nursery and Grower
   
6. Diagnostics and Veterinary Services
   
7. Vaccinations and Tests
   
8. Quick View Pathologies Table
   
9. References

“Something is being lost.” This statement has come out more than once from the farmers and veterinarians who contributed to this guide, Managing for Herd Health in Alternative Swine Systems. The kind of management that makes these systems succeed is becoming rare as the number of hog farmers in Iowa has dropped by two-thirds in just the last decade, the greatest losses among small and moderatesized operations. Yet there are producers and veterinarians who not only retain the old husbandry skills but are bringing 21^st century science into the picture. Take this guide as an invitation to join them.

If the guide were computer software, it would be version 1.0. There will be updates, corrections, and ideas for revisions. So check with a vet to confirm what you read here. And as changes are made, the current version of chapters will be posted on the Farming Systems Program website at www.pfi.iastate.edu/pigs.aspx (or reach it through the Programs section of the Practical Farmers of Iowa website at www.practicalfarmers.org). There you will also find a place for entering your own comments and suggestions. Or contact us directly (515-294-5486, [email protected]). We would like to hear from you!

As this herd health guide was being created, a companion guide focusing on managing for production was also being written at Iowa State University. The Niche Pork Production Handbook deals with management topics not covered here (www.ipic.iastate.edu/publications/IPICNPP.pdf).

The acknowledgements on the following page show many people contributed to this guide. Veterinarians were particularly important in sections on biosecurity, vaccinations, and disease details. Both vets and producers had a hand in the case study examples. These appear alongside the main text and provide real-life illustrations of points raised. Finally, producers get much of the credit for the “words of wisdom (WoW)” quotes that also appear throughout the text. These are lessons learned, sometimes the hard way, and although they may be humorous are worth keeping in mind.

Acknowledgement and Thanks

This herd health guide is a product of The Research Alliance for Farrowing: The Weak Link in Alternative Swine Systems, a project carried out from 2003-2007 with support from the North Central Region SARE Program (Sustainable Agriculture Research and Education) of the United States Department of Agriculture under a cooperative agreement with the University of Nebraska. Since 1988, SARE has advanced farming systems that are profitable, environmentally sound and good for communities. (www.sare.org)

The need for the Research Alliance for Farrowing (RAF) project was first voiced by farmers participating in the Pork Niche Market Working Group (PNMWG), a diverse collection of marketing businesses, organizations, academics, and producers working to advance value-added opportunities. Those farmers identified the early life of their pigs as a stage whose health problems were cutting into their success and preventing additional farmers from adopting alternative systems. The roots of the RAF project and of this herd health guide are in PNMWG, which is led jointly by Practical Farmers of Iowa and the Leopold Center for Sustainable Agriculture. The Leopold Center has also aided the RAF project through its Value Chain Partnerships for a Sustainable Agriculture, funding project evaluation and production of some of the case studies appearing in this herd health guide. Finally, encouragement and ideas have come from a parallel project on herd health and farmer records funded by the National Research Initiative (NRI).

RAF undertook intensive evaluation of a number of alternative swine systems. It also worked to develop discussion about alternative systems among veterinarians. At a project workshop for vets in 2004, Iowa State University veterinarian Patrick Halbur recognized the need for a herd health guide for alternative production systems. In what became a three-year process, drafts of this guide have received comments and invaluable contributions from ISU vets, field veterinarians, and producers. Special credit is due Dr. George Beran, whose deep understanding of the human-pig relationship always brought us back to the basics, and Dr. Kurt Van Hulzen, who contributed much practical and current knowledge. The people named below have contributed ideas or text or have reviewed drafts of this guide.

R.B. Baker, D.V.M., ISU Dept. of Vet Diagnostic & Production Animal Medicine

Arthur H. Behrens, D.V.M., Templeton Veterinary Clinic, Templeton, IA

George Beran, D.V.M., Distinguished Professor of Preventive Medicine, Emeritus, ISU College of Veterinary Medicine

Robert Bryant, D.V.M., Natural Pork Systems, Aurelia, IA

Ronda Driskill, Practical Farmers of Iowa/ISU Extension

Rick Exner, Practical Farmers of Iowa/ISU Extension

Tom Frantzen, Alta Vista, IA

Patrick Halbur, D.V.M., ISU Dept. of Vet Diagnostic & Production Animal Medicine

Tracy Harper, Harper Consulting, Mindoro, WI

Mark Honeyman, Director of ISU Outlying Research Farms

Gary Huber, Practical Farmers of Iowa

Philip Kramer, Niman Pork Company, Latimer, IA

Vic Madsen, Audubon, IA

Allen Moody, LaFarge, WI

Lyle Rossiter, Manager, ISU Allee Research Farm, Newell, IA

David Stender, ISU Extension Swine Field Specialist, Cherokee, IA

David L. Striegel, D.V.M., Animal Health Center, Sac City, IA

Kurt Van Hulzen, D.V.M., Suidae Health and Production, Algona, IA

Paul Willis, Niman Pork Company, Latimer, IA

Dan and Lorna Wilson, Paullina, IA

Principles & Strategies for Success

Swine success comes in many forms. What do successful producers have in common? They have strategies that work for them. A strategy pulls together practices into a package that works. As a pork producer, you have herd health strategies, production strategies, marketing strategies, and more. And of course, these strategies have to interlock, to work together.

When you are around farmers who have been doing this for a while, you begin to pick up the strategies that they believe are key to success. They have put the pieces together in a way that things work on their farms. And those pieces are based on basic principles. In this herd health guide, you are going to read a lot about the pieces – the practices – but keep in mind that success is more than a collection of practices; it is strategies based on principles, in other words practices-with-a-purpose.

What are some fundamental principles of herd health? In the last four years of working with producers and vets, we have heard the following enough to place them on the level of principle:

• “Control exposure of swine to both normal and pathogenic microbes.” Controlling exposure is absolutely key to success in alternative systems. You need to have control over exposure to the world outside the farm. A disease outbreak can even be triggered by introducing a healthy animal in the wrong way, to say nothing of infected livestock and contaminated people and equipment. Also control exposure of young pigs to organisms already on the farm until their immune systems are ready. That includes exposure to pigs older than they are.
  
• “Maximize the natural resistance of your swine through environment and stress control.” Sanitation is more than public relations. Manure harbors what was ailing the animals plus whatever the flies have added. Beyond that, it can contribute to an air quality that promotes respiratory problems. If the manure gets ahead of the bedding, animals may lack a dry sleeping area where they can maintain body temperature. Poor sanitation lowers animals’ vitality and resistance to disease, killing profits if not animals. And are you ready for this? Bond with your pigs! If they get riled up every time they see you, it contributes to stress levels that are measurable in the blood – theirs and yours. Stress depresses the immune response as well.
  
• “Enhance the disease resistance of your pigs with timely vaccinations and other practices.” In your operation there is a constantly changing balance between pathogens and the resistance that your pigs have to those microbes. You want to enhance that resistance without overwhelming the animal. You protect newborn pigs from pathogens and parasites as much as possible, but you expose their mothers to some pathogens prior to farrowing to maximize resistance. That way newborn pigs acquire temporary, “passive” immunity to those diseases with their first mother’s milk (colostrum). You build immunity in the sow through vaccinations and by the feed-back of manure from the farrowing and production areas of the operation to gestating sows and gilts. Gestating stock also benefit from back-feeding placentas and mummified fetuses from the farrowing barn.

So, given the basic principles of herd health, what are some successful strategies that build on the strengths of alternative swine systems? Here are some candidates; you may have additional strategies.

Some of these principles and strategies may seem to depend on control and barriers, bringing to mind conventional, confinement swine systems. In some ways, the design of conventional systems does make it easier to separate pigs from the outside and from animals of different ages. Alternative livestock systems, because they are more integrated into the whole farm environment, present unique challenges in applying some herd health basics. But it isn’t impossible to manage for these principles and strategies in alternative swine systems. Successful producers are meeting that challenge, and this guide shows that.

Have a Plan and Implement It

There are many, many practices you can use to further your herd health strategies. Decide which ones you are going to implement. It won’t hurt to put it on paper; that may help your thought process, and it gives those around you the opportunity for input. This is the time to get a vet involved if they aren’t already. If you draw up your plan when things are going OK in the swine operation, the plan will describe how you intend to keep it there. If your plan comes out of a crisis, it is the road map for getting back to normal and a set of strategies for maintaining things that way. Plans can be changed, but having a written plan helps you know what there is to change. And remember, we all have great plans, but successful plans are the ones that get implemented.

Review of Managing for Herd Health in Alternative Swine Systems

Part of this swine herd health guide is laid out in the way that you are likely to have questions – by age and type of animal. Each of these overlaps with the others because topics like vaccination, diagnostics, and parasites are not restricted to a single type of pig.

The text of this section previews specifics found in later chapters of this guide. Following this management section is a chapter on biosecurity, pig flow, and introduction of new stock. After that are sections focused on breeding stock, on farrowing, on nursery and grower/finisher pigs, and on vet and diagnostic services. Along the way are examples illustrating points made in the chapters. Also, scattered throughout are quotes from other producers to stimulate your thinking. In addition, near the back of this guide you will find: a table of the most significant swine diseases in alternative systems; a summary of recommended diagnostic tests and vaccinations by pig life stage; results from the NRI on-farm swine health study of alternative systems in Iowa; and a listing of additional references and resources.

Biosecurity, Pig Flow, and Introduction of Stock

Biosecurity

You want to maintain your herd free of specific bacterial, viral, and parasitic diseases. Make the most of isolation; isolation from outside the farm and isolation of different groups of pigs on the farm from each other. It’s easy to see potential contamination in the trailer used to haul pigs to market, the feed truck, the new load of feeder pigs or gilts, or the curious visitor. Your own farm may not seem like another source of disease, but it can be just that.

• Pigs coming onto your farm are a risk. Make it a calculated risk (see the text below on livestock introduction) or find alternatives.
  
• Nursery pigs do not have the immune system to handle all the organisms on your farm, so isolate them from older animals other than their sows. This is another reason to keep the age range of the nursery group tight. Make the most of the passive immunity available through the sow’s colostrum, which you can enhance through vaccination and feed-back of feces and placentas during gestation. (See the sections on breeding herd and nursery pigs.)

• There is a reason veterinarians put on clean coveralls and disposable boots when they come to your farm. Anyone from off the farm entering your swine pasture, barn, hoop, or swine yard should do the same. Farmers too should have a separate pair of coveralls and boots for dropping pigs off at the sale barn/collection point as well as for visiting areas of high swine traffic.
  
• If possible locate your swine facilities and pastures away from neighbors’ swine units and from roads highly traveled by trucks that have been on other swine farms.
  
• If you have feed delivered, know where the truck has been prior to coming to your farm. Seriously consider on-farm grinding.
  
• Rats, mice, birds, and even cats can carry swine diseases. You may conclude that rodent control makes cats worth the hazard as long as they don’t visit other operations. But cats mostly just make the rodents harder to find. Avoid leaving feed bins and feed wagons uncovered. Clean up feed spills promptly. Bird mesh is standard in conventional curtained buildings, and it can also be installed in hoops and barn windows.
  
• Do not feed any food scraps or garbage.

We have summarized several tried-and-true strategies for increasing herd health through managing the movement of livestock. A review of these is an opportunity to expand on the reasons for each:

Closed Herd

The pig is the primary source of all infections, so closing your herd to outside introductions is one way to minimize introducing disease. PRRS (Porcine Reproductive and Respiratory Syndrome) is a recent reminder that disease can get into your system by many routes. That includes animals you bring onto the farm – gilts, boars, and feeder pigs. That is the reason a number of alternative swine farmers are going to a “closed herd” in which animals do not routinely enter the system. This isn’t to say multi-site systems are a bad idea; you just need to define what is “in the system” and what is outside it.

How do you maintain and improve your genetics in a closed herd? Artificial insemination (AI) is an indispensable tool. AI gives you access to almost any genetics you want to utilize. You can even breed some animals for production and others for maternal characteristics that you want to add to your breeding herd. While there are things to know about AI, it is not rocket science. True, it may mean you spend more time observing your sows and gilts. Most farmers moving to a closed herd consider this an acceptable investment for the increased breeding control and biosecurity. Be sure you purchase semen that is certified free of PRRS.

Additionally, you can improve genetics by selecting within your herd. For example:

• One of the most heritable and most important traits is the behavior of the sow. A good sow, with strong maternal traits will raise more pigs. A good sow has nine pigs, and raises eight. This trait is passed on to your gilts, so select your gilts from your best sows. Strong maternal traits in your gilts will improve “pigs out the door” quicker than selection based purely on production genetics.
  
• Select the fastest growing gilts in your herd. The rate of growth is a highly heritable trait, compared to the number born alive.
  
• Gilt selection should begin in their first week of age. By identifying gilts with an ear notch, you can track which gilts came from your best sows. You can also track the age of the gilt to determine which gilts are growing the fastest. The largest gilts in a group may not be the fastest growing, they may just be older. Identification of the gilts will let you quickly determine the age and how fast the gilt grew.

All-in-All-Out (AIAO)

AIAO gives your animals isolation on the calendar. You farrow a large enough group of sows/gilts together that you can fill your nursery and finishing facilities with just those offspring, or maybe you purchase a similarly-sized group of feeder pigs. (Buy them all from one source, and don’t mix them with farm-born pigs.) When that group is ready for market, they all go out the door, and you clean the place up.

• If you have surfaces that you can steam clean, so much the better.
  
• Hoophouses should be scraped down to the dirt and a layer of ag lime spread before new bedding is added. Some producers only completely clean out the hoops once a year, simply removing wet spots and re-bedding for the other batch. Of course if you clean out a hoop in winter, re-bed immediately to prevent the ground from freezing.
  
• Leave the cleaned facility empty for at least two weeks to further reduce the pathogen load.
  
• Holding back the runts and putting them with the next group of pigs is exposing those pigs to the sickest animals of the previous batch. If you keep tailenders, do so in a spot well away from other production facilities. Visit them last in your round of chores.
  
• You are going to have many other questions as you move to AIAO. How big a group of sows should I breed to fill my facilities? How many boars do I need? What is the ideal farrowing window? How do I set up a production schedule and work back from there to breeding dates and weaning dates? Any swine vet or Extension swine specialist will have extensive production knowledge of pig flow, record keeping and analysis, and business planning.

See also the forthcoming Niche Pork Production Handbook from Iowa State University Extension (http:// www.pnmwg.org).

Separation by Age

There are production reasons to have age and size uniformity in a group of pigs, but there are herd health reasons as well. How do you manage a nursery group when some animals are young enough to have passive immunity from the sow’s colostrum and others are vulnerable? Or if some are too young to vaccinate while others are at the stage it should be done? Additionally, maternal antibody decay is organism dependent¹. That is why timing of vaccination is so critical. If you make up a nursery group or a finishing group from batches of different aged pigs, then the older pigs, which have had time to acquire germs and parasites, share those all at once with the younger pigs. Keep grower pigs away from gilts and dry sows as well.
¹For example, passive immunity to PRRS lasts about five weeks. Passive immunity to swine influenza persists 9-12 weeks. Every time baby pigs double their weight, their passive antibody levels are reduced by half.

Production experts suggest a maximum age span of 7-14 days for a group of pigs, and this is also desirable for the health of the herd. There is evidence a one-week spread is best, although that may be difficult to manage practically. However, limiting your sows’ exposure to a boar to a maximum of 30 days after they wean, is an easy thing to incorporate that will help reduce the age spread of the pigs. In a 30- day period, a weaned sow will have two opportunities to be bred. Her first opportunity will be 4 to 7 days after weaning. A majority of the sows will cycle in this period. This will be the first group to farrow, and their pigs can be grouped together. The second period the sow has in which to be bred will occur approximately 25 to 30 days after weaning (18 to 21 days after her first cycle). If she does not get pregnant during either opportunity, she is likely not going to get bred. Also, sows that do not get bred within the two cycles after weaning have significantly smaller litters. Leaving a boar in for more than 30 days only results in a bigger spread in your baby pigs, which means more stress and a higher pathogen load.

AI workshop, Research Alliance for Farrowing project.

Even if you raise your own gilts, they may have a lower gastrointestinal parasite load or lower parasite immunity than the sows that have been around for years. You can alleviate the infection potential by treating sows and gilts with a wormer one week before they farrow. (Certified organic swine producers can treat breeding stock only before the third trimester.) In any event, you want to avoid a situation in which naive animals are hit immediately with a parasite load from their mother or their environment. Your strategy as an alternative producer is to expose pigs gradually to parasites and microbes as their growing immune systems strengthen.

Separation of Units and Multiple Sites

Separation might seem impractical on a diversified farm where cropping and different livestock enterprises carry on in close proximity, where one hoophouse is 10 feet from the next, or where Cargill-type pens are lined up side-by-side along a concrete pad. Again, you can make sunshine and fresh air work for you. Ten feet of separation is far better than none at all. If you don’t fill every Cargill pen, you can break that nose-to-nose contact down the line.

Make sure that a fence is really a fence. This isn’t easy with pigs, but all it takes is one little pig wandering all over the operation to share every germ around. There is another equally sinister side when this becomes common, and that is cross-fostering. The wandering pigs find a nursing sow, displace her newborns, and move in. They live high on the hog on milk they don’t need, while the sow’s piglets starve to death in the straw. At the very least, make sure that nursing sows and their litters are securely fenced. A problem like this is minimized with a two-week farrowing window.

As mentioned above, some alternative systems are using multiple sites to help ensure biosecurity. In some cases two farmers accomplish this by working together. One only farrows; the other finishes. The finisher never steps foot in the farrowing-only operation, and vice versa. Together they accomplish something that would take a much larger single operation. Wherever you set the boundaries, do not allow employees to own or contact pigs outside of the system, and establish procedures for movement within the system.