N O. 3 I N N O V A T I O N S A N D P R A C T I C A L A D V I C E F O R S U C C E S S F U L F L O C K C A R E POULTRY H E A L T H TODAY p o u l t r y h e a l t h t o d a y. c o m S h r e w d M o v e S Like a chess match, anticoccidial rotation is a game of strategy at wayne Farms It s back: Zoamix adds flexibility to rotation plans 6 Specialists share ideas on antibiotic-free production 12 Got Maxima? New sampling procedure aids detection 25 7 U S e d i t i o n ZP130608
I N N O V A T I O N S A N D P R A C T I C A L A D V I C E F O R S U C C E S S F U L F L O C K C A R E POULTRY H E A L T H TODAY w h a t s i n s i d e c o v e r S t o r y w o r d s & N u m b e r s 10 4 7 54300 Memorable quotes and figures from the world of poultry health s h r e w d m o v e s d i s c o v e r i e s 5 Like a chess match, anticoccidial rotation is a game of strategy at Wayne Farms Rotating anticoccidials is a lot like playing chess, says Mark Burleson, DVM, head veterinarian at Wayne Farms. Your next move might address an immediate need, but it also could determine what pieces are still standing later in the match. It is, after all, a game of strategy. Study shows benefits of classic reovirus vaccine Zoamix returns to help US producers battle coccidiosis p o u l t r y h e a l t h t o d a y. c o m Sponsored by
3 s o u N d s c i e N c e 23 N o w o N l i N e 30 S P e c I a L r e P o r t 12 Sericea lespedeza found ineffective for coccidiosis control S. Heidelberg colonization reduced with in-feed treatment Wet litter, footpad dermatitis hurt broiler performance d i a g N o s t i c s Got Maxima? New sampling procedure aids detection in broilers Reducing false positives pays in ELISA Mycoplasma testing 25 Poultry Health Today s redesigned website features even more news and information to help optimize the health and performance of your birds. t h e l a s t w o r d 31 Is it right or even ethical to ask poultry veterinarians to avoid using FDA-approved antibiotics solely for marketing reasons? Lloyd Keck, DVM, doesn't think so and he explains why. Raising poultry without antibiotics While the US poultry industry has responded quickly to growing consumer demand for birds raised without antibiotics, the trend has also led to increased pressure from enteric diseases, declines in feed efficiency and higher production costs. It has also created a dilemma for veterinarians. Poultry-health experts, pioneers in antibiotic-free production and opinion leaders recently met to share experiences and offer suggestions for managing this emerging market.
I N N O V A T I O N S A N D P R A C T I C A L A D V I C E F O R S U C C E S S F U L F L O C K C A R E POULTRY H E A L T H T ODAY w o r d s & N u m b e r s 56% 10 54300 Consumers who said they had no primary source for animal-welfare information in a Purdue University survey. Those who did relied mostly on animal protection groups. 1/3 Fraction of respondents in US consumer survey who believe that the agriculture industry is transparent SoUrce: wat tagnet Number of food-borne illnesses due to Salmonella and Campylobacter that USDA claims will be prevented by new poultry inspection system 5,000 I, too, want antibiotics to work. I also know that some bacteria are extremely adept at developing resistance, and not all antibiotics work for all bacteria. The discussion of antibiotic resistance should not be an emotional issue but rather one for the real experts. dr. yvonne vizier thaxton, director, center For Food animal well-being, UNIverSIty of arkansas 15% Ratio of DDGS in poultry feed associated with increased risk of severe necrotic enteritis in Auburn University study We need to own our industry and stand up for it If we don t own our own industry, and we don t start talking outside the bubble I can t blame the activists and detractors for telling our story for us. emily MeredIth, animal agriculture alliance 4
3 d i s c o v e r i e s Zoetis veterinarians initiated a study after a substantial increase in reovirus tenosynovitis occurred in several US broiler-producing regions during the winter of 2011-2012. impact of classic reovirus vaccine antibodies studied A recent study showed that broiler chicks receiving higher reovirus antibody levels from conventionally vaccinated hens had a lower incidence of tendon swelling and were protected from weight suppression caused by Variant Group-1 (VG-1), Kalen Cookson, DVM, director of clinical research, Zoetis Inc., said at the 2014 International Poultry Scientific Forum. 1 Zoetis veterinarians initiated a study after a substantial increase in reovirus tenosynovitis occurred in several US broiler-producing regions during the winter of 2011-2012. Previous research has indicated that live reovirus vaccines such as S-1133 given to broilers may have limited efficacy against VG-1, but a study of maternal antibody levels from commercial killed vaccines had not been reported, Cookson explained. In the study, investigators raised 400 Cobb-500 chicks from two breeder flocks, designated as Flocks A and B, on fresh shavings until 5 days of age, when they were commingled and placed into floor pens. The researchers then initiated three challenge treatment groups: One received classic S-1133 reovirus via footpad injection, the second group received VG-1 reovirus via footpad injection and the third group received VG-1 via intratracheal inoculation. A fourth group received saline only in the footpad and served as a control. Investigators measured bodyweight and footpads every 3 days until 21 days of age. They also tested serum for reovirus antibodies and confirmed that chicks had antibodies only to classic reovirus vaccines, not to VG-1. Flock A had reovirus antibodies that were about 50% higher than Flock B s. Weight gain only major difference The only substantial finding between flocks was that Flock A had higher weight gain after VG-1 challenge, and the difference was statistically significant (p 0.05), Cookson said. The incidence of tendon swelling was lowest in the group that received S-1133, followed by VG-1 administered in the footpad. It was highest 80% in broilers that received intratracheal VG-1, Cookson continued. Broilers challenged in the footpad had an incidence of hydropericardium a noninflammatory accumulation of watery fluid in the pericardial cavity that was low at 8%-12%, compared to 40%-46% in the group challenged with VG-1 via the intratracheal route, he said. Hardy virus There have been numerous field reports of VG-1 vertical shedding from hens to chicks but the high incidence of hydropericardium and tendon swelling in the intratracheal challenge group demonstrates that VG-1 is also quite infectious via horizontal, or chicken-to-chicken, exposure, Cookson noted. Therefore, once this virus is introduced, it is capable of sustaining itself on farms over consecutive flock placements. continued p o u l t r y h e a l t h t o d a y. c o m 5
I N N O V A T I O N S A N D P R A C T I C A L A D V I C E F O R S U C C E S S F U L F L O C K C A R E POULTRY H E A L T H T ODAY d i s c o v e r i e s The return of Zoamix could not be coming at a better time. D o N W A L D R I P, D V M, D A C P V impact of classic reovirus vaccine antibodies studied A properly chosen autogenous vaccine may be the most effective way to help protect against VG-1 challenge, but this study suggests that higher classic antibodies can also help provide a moderating benefit, Cookson concluded. 1 Cookson K, et al. Comparison of reovirus challenge viruses s-1133 and variant Group-1 in two commercial broiler flocks with different maternal immunity levels. abstracts, international Poultry scientific Forum, atlanta, 2014. it s back: Zoamix adds flexibility to rotation plans Zoetis Inc. has relaunched Zoamix (zoalene), a versatile synthetic anticoccidial for the prevention and control of coccidiosis in broilers and turkeys. The US poultry industry loses an estimated $600 million a year to coccidiosis, 1 so the return of Zoamix could not be coming at a better time, says Don Waldrip, DVM, DACPV, a senior technical services veterinarian with Zoetis. He notes that US poultry producers have not seen a new in-feed anticoccidial in 15 years, 2 and concerns remain about existing products becoming less effective over time. Having one more anticoccidial to use in a rotation program especially one like Zoamix, which has a unique chemical structure could help preserve the efficacy of other coccidiosis medications, Waldrip says. Versatile product Zoamix is a Type A Medicated Article that can be used safely year-round with no withdrawal. Because it is a synthetic compound, Zoamix is compatible with antibiotic-free or conventional production systems. As with all in-feed anticoccidials, Zoetis recommends resting the medication periodically to maintain good efficacy. According to Waldrip, Zoamix is unique in that it s a synthetic compound but works similarly to an ionophore by allowing some cycling of Eimeria, the parasite that causes coccidiosis. That cycling, commonly called leakage by poultry producers and veterinarians, allows the development of natural immunity against the disease, the veterinarian explains. Waldrip says the arrival of Zoamix would further strengthen Rotecc Coccidiosis Management, a science-based initiative Zoetis launched earlier this year to help poultry producers develop more strategic, cost-effective and sustainable programs for battling the costly parasitic disease. More uses In addition to preventing and controlling coccidiosis in broilers and turkeys, Zoamix can be used for the development of active immunity against coccidiosis in replacement chickens. Zoamix is also approved for use in combination with BMD (bacitracin methylene disalicylate), a feed medication used to manage necrotic enteritis in chickens and transmissible enteritis in turkeys. Formerly produced by Alpharma, Zoamix was used by the US broiler and turkey industries for more than four decades before leaving the market in 2005 due to the shortage of a key ingredient. Zoetis later acquired the product, saw the poultry industry s need for Zoamix, and worked with suppliers to resolve supply issues and relaunch the product. 1 Cracking down on poultry disease with egg yolk. agriculture research. 2012 July;60(6):9. U.s. department of agriculture, agricultural research service. 2 schering-plough animal health (now merck animal health) introduced Clinacox (diclazuril) to the Us in 1999. 6
c o v e r s t o r y s h r e w d m o v e s Like a chess match, anticoccidial rotation is a game of strategy at wayne Farms rotating anticoccidials is a lot like playing chess, says Mark Burleson, DVM, head veterinarian at Wayne Farms. Your next move might address an immediate need, but it also could determine what pieces are still standing later in the match. It is, after all, a game of strategy. On paper, Burleson says, it appears that poultry companies have a smorgasbord of options more than a dozen antimicrobials and six vaccines in the US alone for managing the costly disease, which in its subclinical form can take a huge bite out of feed conversion and growth rate. But in reality, the menu is pretty sparse, he says. continued p h o t o a b o v e : m a r k b u r e l s o N, d v m, w a y N e f a r m s p o u l t r y h e a l t h t o d a y. c o m 7
I N N O V A T I O N S A N D P R A C T I C A L A D V I C E F O R S U C C E S S F U L F L O C K C A R E POULTRY H E A L T H T ODAY The chemicals can be used only one cycle at a time with lots of rest time in between, so that cuts your options in half right there, the poultry veterinarian says. The ionophores can be used longer, but they have their limitations, too. One product can t be used if you're exporting to China, for example. Another one can t be used in the summer. Still, another product is not very good on Eimeria maxima, which is your big feed-conversion killer. So, when you take all those factors into account and consider that some products do better at different stages of the growth cycle, it starts bringing down the number of options pretty quickly. tools in the shed Vaccinating for coccidiosis is a good option for some operations, but getting good vaccine uptake and thereby ensuring good performance is sometimes a challenge. For some operations, supplementing the vaccine with a low level of an ionophore after vaccinal oocysts are done cycling is one option for providing added protection and thereby optimizing bird performance. Whether using chemicals, ionophores, vaccines or a combination of all three, the best solution is to plan long term, Burleson says. We have a lot of tools in the shed, but they re not all available at the same time or for the same job. And remember, most are antimicrobials, so resistance develops. You have to rotate them properly to keep them effective. Burleson says he plans his coccidiosismanagement strategy at least 12 months 8
s h r e w d m o v e s c o v e r s t o r y in advance on paper and even longer in his head. He has a strict rule about never using the same in-feed medication for more than two cycles in Wayne s larger birds, fed to 63 days, and up to three cycles for birds grown to 40 days. I try to be proactive and not wait for leakage to occur before I switch products, Burleson says. I feel like that s the best way to make your products sustainable and be available for use year after year. we have a lot of tools in the shed, but they re not all available at the same time or for the same job. and remember, most are antimicrobials, so resistance develops. you have to rotate them properly to keep them effective. m a r k b u r e l s o N, d v m knowing when to jump Chad Robertson, a grower for Wayne Farms who manages four houses with 68,000 broilers at his farm in Arab, Ala., agrees with Burleson s long-term, judicious approach to coccidiosis management. You definitely need to stay with a program and not be jumping around too much, he says. You also can get into trouble when you try to push the envelope on a program. It s very tempting to ride the train too long before it gets to the station, when in hindsight you should have jumped off. Robertson says his farm s daily weight gain has increased 15 points over the past two grow-outs by focusing more on anticoccidial-rotation patterns, as well as paying more attention to lighting over the feed pans and sanitizing the drinking-water lines. I also like to run vinegar or citric acid at certain ages in the grow-out to try to keep the gut in check, he says. coccidiosis calendar Wayne Farms coccidiosis-management calendar begins in October, when houses are closed up more to conserve heat, thereby increasing chances for wet litter and more coccidiosis pressure. Burleson kicks off the season with nicarbazin in the starter, sometimes feeding it for as long as 28 days in the colder months but always finishing the birds with one of the ionophores lasalocid, monensin, narasin or salinomycin. The chemical-ionophore shuttle continues until March, when Burleson switches to what he calls his spring clean-up with an all-chemical program from start to finish. This past spring, for example, he used decoquinate. continued p h o t o : m a r k b u r l e s o N, d v m ( r i g h t ) w i t h a l a b a m a g r o w e r c h a d r o b e r t s o N p o u l t r y h e a l t h t o d a y. c o m 9
I N N O V A T I O N S A N D P R A C T I C A L A D V I C E F O R S U C C E S S F U L F L O C K C A R E POULTRY H E A L T H T ODAY There s really good performance associated with knocking down the coccidiosis load with a chemical, he says. Gangrenous dermatitis really picks up in the spring. So the more you can knock back coccidiosis, the less dermatitis you re likely to see. two options Following the spring clean-up, Burleson has two options. He either rotates to a vaccine usually Inovocox EM-1, which is administered in ovo at the hatchery or he goes with a carefully orchestrated rotation of ionophores. He takes care not to rotate from one monovalent ionophore (monensin, narasin, salinomycin) to another so that Eimeria organisms are exposed to an anticoccidial from another molecular family. That could be a chemical or the divalent ionophore lasalocid. While anticoccidial rotation is standard practice on all commercial poultry farms, Burleson calls it one of the struggles of the industry. He adds, We need to be smarter about it. We like to use products when they re performing well, obviously, but too often we keep using them until they don t work anymore. For us, after years of using monensin, narasin and salinomycin, we felt like we needed a change of pace on the Gangrenous dermatitis really picks up in the spring. So the more you can knock back coccidiosis, the less dermatitis you re likely to see. m a r k b u r e l s o N, d v m ionophore side, he continues. Over the past 2 years, we ve used a lot of lasalocid and it s performed very well for us. The veterinarian is quick to credit Wayne s head nutritionist, Tom Frost, PhD, who recommended changing the electrolyte levels in the feed with lasalocid to avoid wet litter. So we ll use, say, salinomycin in the starter and then rotate to lasalocid, Burleson says. preventing burnout To prevent product burnout, Burleson keeps a close eye on bird performance, as well as the results of posting sessions conducted every 6 to 8 weeks. But even then, diagnostics only provide a snapshot. For instance, if I m at a posting session and see heavy cycling between 28 and 32 days and typically, we include only two flocks in that age range at a posting session I m then going to the field to look at more flocks in that age range and see if those two flocks were representative of the whole complex, he says. Litter management also affects the success of a coccidiosis program. Between cycles, Wayne Farms has had good results windrow-composting the litter. It heats up litter to around 130 F, which kills Eimeria oocysts and other pathogens. If you can manage that litter properly and bake out the pathogen load, you ll be much better off with your coccidiosismanagement program and make the products more sustainable, he says. As a production veterinarian, my goal is to be sustainable and to raise a healthy chicken. From an animal-welfare standpoint, I try to give our chickens all I can to make sure they re happy and healthy while they re under my watch. Antibiotics, when used judiciously to manage disease, help us to be more efficient, productive and sustainable. 10
s h r e w d m o v e s c o v e r s t o r y with more than a dozen antimicrobials and a half dozen vaccines available for coccidiosis, why are US poultry producers still having such a difficult time managing this costly disease? coccidiosis: why IS It So difficult to MaNaGe? One reason is that the organisms that cause coccidiosis the family of protozoan parasites of the Eimeria genus are highly prolific and remarkably resilient, says Don Waldrip, DVM, senior technical services veterinarian for Zoetis Inc. Coccidia reproduce quickly and in large numbers just one coccidial oocyst (egg) can produce over 500,000 progeny in just 4 to 7 days. The oocysts thrive in warm, humid environments, although coccidiosis is a threat to poultry farms year-round and in arid climates as well, he explains. Eradicating them from poultry farms has proved to be virtually impossible. No matter where you go throughout the world, coccidiosis is considered one of the top diseases of poultry. the oocysts thrive in warm, humid environments, although coccidiosis is a threat to poultry farms year-round and in arid climates as well. d o N w a l d r i p, d v m think ahead Acute outbreaks of coccidiosis can result in severe diarrhea and mortality, but these situations are rare on progressive poultry farms where anticoccidials are routinely used. On most commercial farms, the more common problem is low-level, subclinical coccidiosis. This form of the disease can easily develop when products gradually lose their efficacy and slowly erode growth rate, feed efficiency and flock uniformity, Waldrip says. In layers and breeders, egg production and quality also decline. Low-level coccidiosis is costly and also predisposes flocks to dysbacteriosis, necrotic enteritis, gangrenous dermatitis and other costly health problems, Waldrip says. Developing a long-term, strategic plan 12, 18 or even 24 months out and drawing on the strengths of all available tools is essential for a lasting, sustainable management program. p o u l t r y h e a l t h t o d a y. c o m 11
I N N O V A T I O N S A N D P R A C T I C A L A D V I C E F O R S U C C E S S F U L F L O C K C A R E POULTRY H E A L T H T ODAY s p e c i a l r e p o r t Raising poultry without antibiotics Meeting the challenge while maintaining flock health, welfare and sustainability h I G h L I G h t S o F a r o U N d t a B L e d I S c U S S I o N 12
3 The US poultry industry has responded quickly to growing consumer demand for birds raised without antibiotics. The trend has created several production challenges most notably, increased pressure from enteric diseases, the need for lower bird density, declines in feed efficiency and higher production costs. Questions have also been raised about the practice s long-term sustainability. To help the industry address these issues, Zoetis Inc. organized a roundtable discussion featuring poultry experts, pioneers in antibiotic-free production and opinion leaders to share their experiences and offer insights on this emerging trend. For more on the roundtable and a copy of the proceedings booklet, contact your Zoetis representative or watch for it on poultryhealthtoday.com. Antibiotic-free poultry production remains uncharted territory that s yielding varied results, a few surprises and an ethical dilemma for veterinarians, poultry experts said at an industry roundtable held in July 2014. The biggest stumbling block in antibiotic-free (ABF) systems is preventing necrotic enteritis (NE) without the use of in-feed medications, panelists said at the roundtable, Raising Poultry Without Antibiotics: Meeting the challenge while maintaining flock health, welfare and sustainability. Suzanne Dougherty, DVM, an independent poultry consultant based in Alabama, has been involved with ABF trials for the past 3 years. The results have varied with the geographic location, she reported, but overall, it s been a real challenge to find a program that doesn t lead to NE issues. A production veterinarian speaking anonymously said the experience at his company has been similar. We re finding ABF birds do not perform as well as conventional flocks on feed conversion or livability, and we typically see NE to some degree in trials so far, Practitioner 1 said. Good results For another major poultry producer, however, ABF flock performance has been almost as good and, in some cases, has surpassed conventional flock performance, according to Practitioner 2, who also needed to remain anonymous. continued p o u l t r y h e a l t h t o d a y. c o m 13
I N N O V A T I O N S A N D P R A C T I C A L A D V I C E F O R S U C C E S S F U L F L O C K C A R E POULTRY H E A L T H T ODAY s p e c i a l r e p o r t M o d e r a t o r : t i m c u m m i N g s, d v m, p h d s t e v e d a v i s, d v m c h a r l e s h o f a c r e, d v m, p h d In some cases, ABF flocks start off well, but then the wheels start to fall off due to NE mortality. s t e p h e N s h e p a r d The poultry industry needs to tell its own story and it needs a strategy now. s u z a N N e d o u g h e r t y, d v m It s been a real challenge to find [an ABF] program that g r e g m a t h i s, p h d doesn t lead to NE issues. Grouping ionophores in with other antibiotics for ABF production was a terrible mistake. Everyone is trying to find the silver bullet, but it doesn t exist. 14
3 continued from page 13 We thought our cost [for ABF flocks] in the long run might be 3 to 4 cents per live pound, but we got it down to 1.5 or 2 cents, which is pretty good, he noted. Stephen Shepard, a sustainability expert and director of poultry welfare and auditing at Farm Animal Care Training & Auditing, estimated the cost at about 2 to 3 cents per live pound. v e t e r i N a r y p r a c t i t i o N e r 1 * We re finding ABF birds do not perform as well as conventional flocks on feed conversion or livability v e t e r i N a r y p r a c t i t i o N e r 2 * When we choose not to use ionophores, we re making a decision to let birds die. Let s be frank about it. * Two production veterinarians from major US poultry companies participated in the roundtable with the understanding that their names and affiliations would be withheld in published reports. The University of Georgia s Charles Hofacre, DVM, PhD, said that on some farms ABF flocks start off well, but then the wheels start to fall off due to NE mortality. He hasn t been able to prove it, but he believes the problem is Eimeria, the cause of coccidiosis. As this parasite goes through its life cycle in the bird, it leads to a bacterial imbalance in the gut resulting in excess mucus, which feeds clostridia and leads to NE. Either the coccidia or clostridia build up after a few cycles, causing the ABF program to derail. To maintain success, it s sometimes necessary to move the ABF operation to a new location, off the farm that s having problems, he said. Careful management essential When roundtable moderator Tim Cummings, DVM, PhD, Zoetis, urged panelists to pinpoint keys to success for ABF production, they emphasized that careful attention to flock management is essential. Although his company s ABF program is new and doesn t include an entire complex, Practitioner 2 credited two factors for the early success. First, the company always starts ABF flocks with a new, clean slate, including fresh litter, and it adheres to the Global Animal Partnership program, a five-step program for rating animal-welfare standards. continued 15
I N N O V A T I O N S A N D P R A C T I C A L A D V I C E F O R S U C C E S S F U L F L O C K C A R E POULTRY H E A L T H T ODAY s p e c i a l r e p o r t Dougherty said, when it comes to ABF birds, It s got to be back to basics. Brooding those first 7 to 10 days whether it be density, clean litter, feed and water availability all those things are critical. Diets must consist of high-quality ingredients. Consider the age of the corn since there is a higher risk that older corn will contain mold and mycotoxins, which can damage the gut and increase the risk for NE. Feed form and particle size are important too, she said. A coarser diet is better for ABF broilers, Practitioner 2 said. When it comes to feed form and particle size for ABF birds, the bigger, the better. His company also dumbed down the starter diet to include less protein since high protein has been associated with the development of NE. Pulling animal protein reduces the likelihood of clostridial contamination and spores in the feed. Hofacre agreed that diet is key in ABF production and said he has also noted a move away from animal byproducts toward an all-vegetable diet for ABF flocks. Practitioner 1 added that it s especially important with ABF flocks to have good ventilation and to keep litter moisture to a minimum, while Davis said his research indicates that one way to help decrease NE mortality is by warming birds to slow feed consumption. It s like the heavier they are, the harder they fall. Steve Davis, DVM, of Colorado Quality Research, said, There s no doubt that high protein in the diet can definitely have an adverse impact. But he doesn t think it s simply due to gut irritation caused by animal byproducts. I think poor-quality animal byproducts are actually a good source of clostridium, the pathogen linked to NE. Managing NE No silver bullet The panelists shared their experiences with alternative products for managing NE, such as essential oils, acidifiers or probiotics. Greg Mathis, PhD, founder of Southern Poultry Research in Georgia, said that in some cases these products just aren t going to do it. They may perform well in a trial, he added, but they don t in the field where there are more variables. Davis defines high protein as levels above 20% to 22% and says this can greatly increase the incidence and severity of an NE outbreak. It appears that getting broilers on grower feed that s 18% or lower before they hit the critical age of 17 days reduces the incidence and severity of NE that can be produced in models. Dougherty added, Most producers raising ABF flocks have had to switch to an all-vegetable diet with no animal protein, which is less likely to contain clostridium and other bacteria. Davis said, Everyone is trying to find the silver bullet, but it doesn t exist. In fact, in his experience, there are more alternative products that make NE worse than there are alternatives that make it better. He and Hofacre pointed out that clostridia that cause NE can vary significantly from farm to farm; an alternative product might modify gut flora and look good in a challenge study but just won t work the way an antibiotic does. continued on page 18 16
3 Keys to successful ABF production Panelists offered these suggestions for successful ABF production: a b f p r o d u c t i o n 1 2 3 4 5 6 7 8 9 Pay careful attention to flock management. Lowering bird density and ensuring good access to food and water are especially important the first 7 to 10 days of life. Start with clean litter and control litter moisture to minimize coccidiosis pressure; make sure ventilation is adequate. Feed a coarse diet with high-quality ingredients and not too much protein; make sure to avoid mycotoxins. Warm birds to slow down feed consumption, which can help reduce necrotic enteritis (ne). Beware of unproven feed additives. there is no silver bullet product that will prevent ne, although enzymes that increase the digestibility of starches can be beneficial for abf flocks on an all-vegetable diet. Inspect hatchery equipment to make sure all chicks are vaccinated effectively. try to use coccidiosis vaccines well before their expiration date. Preserve efficacy of synthetic anticoccidials by using them sparingly; never rotate to a synthetic that s in the same class as the one you were using. Stay flexible. if birds in abf programs start experiencing ne problems, it may be necessary to move the operation to another location. Have a back-up plan. if abf birds get sick, it may be necessary to switch them to conventional production so they can be treated effectively with antibiotics. p o u l t r y h e a l t h t o d a y. c o m 17
I N N O V A T I O N S A N D P R A C T I C A L A D V I C E F O R S U C C E S S F U L F L O C K C A R E POULTRY H E A L T H T ODAY s p e c i a l r e p o r t One exception is enzymes, which have been shown to benefit ABF flocks on all-vegetable diets. In these situations, Davis explained, nutrients are not highly digestible by the bird but are digestible by bacteria. Enzymes can increase the digestibility of nutrients so they don t get farther down into the intestines, toward the ceca, and change gut flora to an environment that s favorable to clostridia and the development of NE, he explained. flocks broke with NE, though in some cases it occurred in only one house on a six-house farm. Mathis emphasized that for successful coccidiosis vaccination, product quality and vaccine application are important. As you get closer to the vaccine s expiration date, quality declines, he said, noting that he would like to see higher levels of coccidial oocysts in vaccines. Coccidiosis management Experience with coccidiosis and ABF flocks has differed just as it has with NE. While Mathis said he considers ABF production synonymous with coccidiosis, Dougherty said she has found the disease isn t always the primary problem. For coccidiosis management, the use of vaccines instead of synthetic anticoccidials, which are allowed in ABF production, has proved to be unpredictable. Sometimes vaccines work fabulously, and sometimes they don t, Dougherty said, adding that more work needs to be done to ensure better vaccine application and uniformity. We have a long way to go with vaccines in ABF production. Practitioner 1 said his company used coccidiosis vaccines in trials designed to mimic ABF production. Nearly every time, he added, Vaccines are fine if all the birds get it. If you made sure every single bird were inoculated, you d never have an issue with coccidiosis. But that s not the way it is, he said. Mathis emphasized the importance of preserving synthetic anticoccidials, particularly in ABF production schemes that prohibit the use of ionophores. He expects nicarbazin to be around for a while despite his own reports of some slippage, which he attributed to sampling at the end of winter. Sampling in the fall likely would have produced better results, Mathis explained. All the synthetic anticoccidials should be used sparingly, and, if new ones become available, their efficacy really needs to be protected by rotating products. We screwed up with Clinacox [diclazuril], which was overused by the US poultry industry when it was introduced in 2003. That led to resistance issues, he said. A B F FACTS & FIGURES 1 2 % t o 1 5 % o F U S P r o d U c t i o n i S n o w e S t i m At e d t o B e A B F. a b f p r o d u c t i o N i s e x p e c t e d t o d o u b l e B y 2 0 1 9 A n d m A k e U P o n e - t h i r d o F U S P r o d U c t i o n ; S o m e t h i n k i t w i l l t r i P l e o r q U A d r U P l e. 18
3 Vaccines are fine if all the birds get it. If you made sure every single bird were inoculated, you d never have an issue with coccidiosis. But that s not the way it is. g r e g m a t h i s, d v m Gangrenous dermatitis One pleasant surprise with ABF production has been a decrease in gangrenous dermatitis, a disease that s been a non-issue in ABF flocks, Dougherty said. Ethical dilemma All panelists lamented the mandatory exclusion of ionophores from ABF programs. While ionophores are used solely for managing coccidiosis, a parasitic disease, they are still classified as antibiotics and, therefore, cannot be used in ABF programs. Grouping ionophores in with other antibiotics for ABF production was a terrible mistake, Mathis said, adding that it is difficult to manage the disease effectively and ably without having them in a rotation. In addition, more pressure from coccidiosis makes birds more susceptible to NE. I never thought we d surpass the Europeans in forgoing ionophores, Practitioner 2 said, adding that they are still widely used in Europe even though the EU banned the use of other feed antibiotics in 2006. That s been a big surprise for me. Davis, who has worked extensively with NE models, said, It s very interesting. I ve never seen a broiler farm break with NE early, then break later with dermatitis. The panel agreed that the trend toward ABF production was creating an ethical dilemma for veterinarians charged with ensuring the health and welfare of broiler flocks. Hofacre likewise reported seeing less gangrenous dermatitis in ABF flocks, even in complexes that seemed prone to the problem. He suggested that a change in the intestinal microflora might explain the phenomenon. On one hand, they noted, veterinarians took an oath to use [their] scientific knowledge and skills for the benefit of society through the protection of animal health and welfare, the prevention and relief of animal suffering, the conservation of animal resources, s y N t h e t i c a N t i c o c c i d i a l s ( c h e m i c A l S ) A r e n o t c l A S S i F i e d A S A n t i B i o t i c S A n d A r e S t i l l U S e d e x t e n S i v e ly i n A B F P r o d U c t i o n, U S U A l ly i n r o t At i o n w i t h v A c c i n e S. u s d a i N s p e c t s F o r A n t i B i o t i c r e S i d U e S t o e n S U r e t h At A l l m e At i S A n t i B i o t i c - F r e e r e g A r d l e S S o F h o w P o U lt r y w A S r A i S e d. p o u l t r y h e a l t h t o d a y. c o m 19
I N N O V A T I O N S A N D P R A C T I C A L A D V I C E F O R S U C C E S S F U L F L O C K C A R E POULTRY H E A L T H T ODAY s p e c i a l r e p o r t the promotion of public health, and the advancement of medical knowledge. Yet, some poultry companies are asking their veterinarians not to use antibiotics that FDA has said are safe and effective. In particular, they were concerned that they cannot use animal-specific antibiotics that are not important to human medicine, such as ionophores and other antibiotics that help maintain good intestinal health in poultry. Tough decisions Call for public education Hofacre noted that activist groups have taken control of messaging to consumers and we in animal agriculture have not done a good job responding. Other panelists said restaurants are driving the ABF movement, believing they can differentiate their product and attract more customers if they advertise their meats as antibiotic-free, said Practitioner 1. Raising flocks without ionophores, Practitioner 2 said, creates both animal-welfare and public-health issues. We know ionophores are safe, yet we re not using them in ABF systems. When we choose not to use ionophores, we re making a decision to let birds die. Let s be frank about it, he said. Dougherty said it s ironic that consumers who want ABF poultry are often the same people who insist on good animal welfare. There s a big disconnect there about understanding what the removal of antibiotics from poultry production truly means, she said. It s a real challenge to balance ABF with animal welfare. Davis called it a dilemma driven by consumer ignorance. He added, It s a fact that organic and ABF birds have a higher incidence of pathogens such as Salmonella and Campylobacter and a higher 7-day mortality. We re actually producing a product that s not as safe for people or as good for birds. It s in direct conflict with the oath we ve taken as veterinarians. If we were in the business of raising puppies and were allowing them to die, it would be easy to educate the public and stop whatever practices were causing the deaths, he said. If it were the public or consumers who felt their health was truly at risk because of our use of antibiotics, that would be one thing, he added. But I feel like a lot of this [movement] comes from businesses and it s a business decision aimed at making more money. That s my frustration. Asked by Cummings exactly how the poultry industry can get its message out, panelists offered several ideas. Dougherty said more careful consideration needs to be given to the way poultry and poultry products are labeled and to terminology. For example, it s well documented that some antibiotics improve intestinal health and thereby result in better feed conversion and growth rate. In hindsight, calling some antibiotics antibiotic growth promoters wasn t the smartest thing to do, Dougherty said, and the public probably isn t going to understand what the judicious use of antibiotics means. Although they don t have the money activists do to conduct campaigns, veterinarians are the best ones to deliver messages to the public about poultry production because they are one of the most respected and trusted professions, she said. Davis suggested poultry veterinarians consider forming an organization devoted to promoting the welfare of chickens; continued on page 22 20
3 what poultry is really raised without antibiotics? A variety of terms are used to describe poultry raised without antibiotics. Some are USdA approved and verified, but others are not. here s a look at what consumers are seeing in their meat cases: Never Ever 3 No antibiotics added No antibiotics ever No antibiotics administered Raised without antibiotics Antibioticfree Never Ever 3 is a USDA-verified and -monitored marketing claim that means No Antibiotics Never Ever, No Growth Promotants Never Ever and No Animal Byproducts Never Ever. Animals that have received any of the Never Ever 3 prohibited substances must be identified as nonconforming and removed from the program. Under this program, poultry cannot receive antibiotics in feed, water or by injection from birth to slaughter, including low-level or therapeutic doses, sulfonamides and ionophores. However, ionophores a type of antibiotic shown to be effective against Eimeria, the parasite that causes coccidiosis may be administered as anticoccidials. Programs requesting approval to use ionophores as anticoccidials must provide a parasite-treatment and -control plan as part of their quality-management system and must meet the USDA Food Safety and Inspection Service (FSIS) labeling requirements specific to the use of ionophores as anticoccidials to prevent parasitism, according to USDA. Fish byproducts and vitamin and mineral supplementation are permissible. No antibiotics added and No antibiotics ever are phrases permitted by USDA s FSIS and may be used on labels for meat or poultry products if sufficient documentation is provided by the producer to the agency demonstrating that the animals were raised without antibiotics. No antibiotics administered and Raised without antibiotics are general claims that imply that no antibiotics were used in the production of a food product and are considered acceptable by USDA, which is accountable for proper use of these claims. However, there is no verification system in place. Antibiotic-free is not a phrase authorized by USDA, which inspects all meat for residues of antibiotics, chemicals and other substances. No meat sold in the US is allowed to have antibiotic residues, so technically, it s all antibiotic-free. p o u l t r y h e a l t h t o d a y. c o m 21
I N N O V A T I O N S A N D P R A C T I C A L A D V I C E F O R S U C C E S S F U L F L O C K C A R E POULTRY H E A L T H T ODAY s p e c i a l r e p o r t Hofacre concurred but suggested adding poultry farmers to the group. To me, that s the way to go, the professor said. Have young farmers go hand-in-hand with veterinarians to put a face on the poultry industry and get across the point that farmers want to take good care of their animals and don t want them to die. Need specific guidelines There s a big disconnect there about understanding what the removal of antibiotics from poultry production truly means. s u z a N N e d o u g h e r t y, d v m Hofacre thinks it would also be helpful if the American Veterinary Medical Association (AVMA) established a vehicle for countering activist marketing pressure. The AVMA could establish more specific guidelines about when to initiate antibiotic treatment, perhaps based on increased morbidity or mortality. Then poultry producers could say to customers that they are following AVMA guidelines, he said. One panelist suggested a public-education campaign that has shock value by showing the consequences of removing antibiotics from poultry production. Pictures of sick chickens, for instance, might get the public s attention and really make a difference. Shepard urged the poultry industry to be more proactive and transparent on the antibiotic issue. it s clear they have misconceptions just like many consumers; some mistakenly think chickens are raised with hormones and steroids. The industry also needs to have a meaningful discussion with food vendors, Shepard said. To illustrate his point, he told of one retailer who called to ask how much cage space a certain broiler producer provided for its birds. When Shepard replied, There are no cages, the caller couldn t believe it. Hofacre said educating the media was equally important, adding that he recently met with an agriculture reporter who had never met a farmer. I think the ball s in our court and needs to start within poultry operations, he said. Upon talking to poultry company employees, The poultry industry, Shepard concluded, needs to tell its own story and it needs a strategy now. 22
3 s o u N d s c i e N c e The results of this study indicate that SL has no anticoccidial activity against Eimeria species in the chicken. t. r a t h i N a m Sericea lespedeza found ineffective for coccidiosis control in chickens Sericea lespedeza (SL), a warm-season legume shown to help control coccidiosis in lambs, 1 had no anticoccidial activity in chickens, according to a study conducted at the University of Arkansas. 2 Investigators fed different levels of SL in the diet of chickens after they were orally infected with Eimeria acervulina, Eimeria maxima or Eimeria tenella, three of the several Eimeria species that cause coccidiosis in chickens. They evaluated the effect of SL on the ability of coccidia to replicate in the intestines and its effect on bodyweight gain, feed intake and feed-conversion ratio (FCR). Chicks infected with a low, 500-oocyst dose of E. acervulina or E. maxima did not differ in the numbers of oocysts they produced in feces whether they were given 0%, 1%, 2% or 4% SL in the diet. In addition, investigators saw no significant difference in weight gain, feed intake or the FCR of birds infected with high doses of E. acervulina or E. maxima (200,000 or 100,000 oocysts/bird, respectively) whether 0%, 1%, 2% or 4% SL was included in feed. There were no significant differences in the numbers of oocysts in feces, in weight gain, feed intake or the FCR among birds infected with E. tenella at low or high doses when 4% SL was included in feed. The results of this study indicate that SL has no anticoccidial activity against Eimeria species in the chicken, say T. Rathinam and colleagues in Veterinary Parasitology online. S. Heidelberg colonization reduced with in-feed combination treatment Broilers that received bacitracin methylene disalicylate (BMD ) plus a probiotic selected for its ability to survive the feed-pelleting process had a markedly lower prevalence of Salmonella Heidelberg colonization, reported Charles Hofacre, DVM, PhD, of the University of Georgia, at the 2014 International Poultry Scientific Forum. 3 S. Heidelberg is the third-leading cause of human food-borne illness from Salmonella. Probiotics such as Lactobacillus administered in water can help reduce Salmonella colonization, but ease of use or consistency of application can be problematic, he explained. Therefore, Hofacre and colleagues tested the use of the spore-forming bacteria Bacillus spp., which can survive the feed mill pelleting process and be consistently and uniformly fed to chicken flocks. In their study, one group of broilers was vaccinated against coccidiosis and then received the probiotic Bacillus licheniformis. Another group received BMD in the starter/grower feed plus the probiotic and salinomycin. A third group served as a control and received no treatment. continued p o u l t r y h e a l t h t o d a y. c o m 23
I N N O V A T I O N S A N D P R A C T I C A L A D V I C E F O R S U C C E S S F U L F L O C K C A R E POULTRY H E A L T H T ODAY Broilers that received the probiotic or BMD s o u N d s c i e N c e plus the probiotic had a markedly lower prevalence of S. Heidelberg... S. Heidelberg colonization reduced with in-feed combination treatment Investigators took drag swabs in all pens on 1, 14 and 42 days of age, as well as 10 ceca samples at 42 days of age, Hofacre said. Broilers that received the probiotic or BMD plus the probiotic had a markedly lower prevalence of S. Heidelberg compared to controls. The odds of Salmonella detection was 77% lower in broilers receiving the BMD-probiotic treatment and 60% lower in broilers receiving only the probiotic. They also had a markedly lower feed-conversion ratio and high average bodyweight gain to 42 days of age, he said. this study has demonstrated that a pelleting-temperature-tolerant Bacillus licheniformis can be used to successfully reduce the prevalence of Salmonella Heidelberg colonization in broilers to 42 days of age, Hofacre said. wet litter, footpad dermatitis tied to reduced broiler performance Increased litter moisture not only led to severe footpad dermatitis (FPD) in broilers, it reduced other aspects of animal welfare and negatively affected performance and carcass yield, Dutch investigators say. 4 They conducted their study to determine if the high level of FPD in broilers caused by wet litter is accompanied by other negative effects on animal welfare, bird performance and carcass yield. Toward this end, they increased moisture by spraying litter with water when broilers were from 7 to 36 days of age; they then compared the results with a control group of broilers kept on relatively good-quality litter and with a low prevalence of footpad lesions. At 21 days of age, the broilers on wet litter had more FPD compared to controls; from 28 days of age onward, they had lower bodyweight gain, lower feed and water intake, higher feed-conversion ratios and more birds were rejected for commercial parts, the investigators say. The broilers on wet litter, furthermore, had more hock burns and breast irritations at 21 and 36 days of age, and locomotion as evidenced by a higher gait score at 36 days of age was negatively affected, the investigators reported in the Journal of Applied Poultry Research. 1 taking stock, Controlling Coccidiosis in Lambs. american society of animal science. dandra avant/usda-ars. http://takingstock.asas.org/?p=8261. accessed april 8, 2014. 2 vet Parasit 2014, January 31. epub ahead of print. http://www.ncbi.nlm.nih.gov/pubmed/24594212. accessed april 8, 2014. 3 hofacre C, et al. reduction in Salmonella Heidelberg shedding and colonization using a Bacillus licheniformis probiotic, optibac-l and an antibiotic Bmd in broiler chickens. abstracts, international Poultry scientific Forum, atlanta, 2014. 4 de Jong ic, et al. wet litter not only induces footpad dermatitis but also reduces overall welfare, technical performance, and carcass yield in broiler chickens. J appl Poult res 2014;23(1): 51-58. 24
3 g o t m A x i m A? n e w S A m P l i n g P r o c e d U r e A i d S d e t e c t i o n i n B r o i l e r S d i a g N o s t i c s Better diagnosis will, of course, enable more effective coccidiosismanagement rotation programs to be developed and, in the long run, will help maintain the economic performance of birds and help secure the long-term A modified sampling procedure developed by researchers at Zoetis Inc. has dramatically improved the detection of Eimeria maxima infection in broilers. In a recent study using the new sampling procedure, the researchers detected E. maxima in 39% of sampled birds, compared to only 1.9% when using the industry s traditional sampling method, reports parasitologist Stuart Andrews, PhD, a poultry veterinary manager for Zoetis who played a key role in the development of the new procedure. was frequently under-diagnosed using the industry s standard Johnson and Reid lesion-scoring system. The difficulties with E. maxima diagnosis have been a common topic of discussion with broiler integrators and their veterinarians, Andrews says, explaining why his group decided to explore a new sampling procedure for the elusive pathogen. t r A d i t i o n A l m e t h o d v A g U e future of the anticoccidials they use. S t U A r t A n d r e w S, P h d We ve found that to improve E. maxima diagnosis, fresh mucosal scrapings must be taken from the mid-intestinal region, even in the absence of small red petechiae, he says. This is in contrast to the traditional Johnson and Reid lesion-scoring method, when fresh mucosal scrapings are taken only when small red petechiae are observed. Zoetis routinely performs coccidial lesion scoring for major broiler companies to help them diagnose coccidiosis, identify the predominant species of Eimeria on specific farms and develop effective coccidiosis-management plans. Over the years, the company noted that E. maxima Diagnosing E. maxima is not difficult when there are numerous E. maxima lesions and other signs of coccidiosis damage corresponding to scores 3 or 4 according to the Johnson and Reid system, but extreme cases such as these are rarely seen, he explains. The problem has been identifying mild to moderate E. maxima infection in birds with scores of only 1 and 2. Although it s long been a valuable tool for coccidiosis management, the Johnson and Reid method for detecting these less severe E. maxima lesions leaves room for subjective interpretation, Andrews says. continued p o u l t r y h e a l t h t o d a y. c o m 25
I N N O V A T I O N S A N D P R A C T I C A L A D V I C E F O R S U C C E S S F U L F L O C K C A R E POULTRY H E A L T H T ODAY d i a g N o s t i c s g o t m A x i m A? n e w S A m P l i n g P r o c e d U r e A i d S d e t e c t i o n i n B r o i l e r S The difficulties with E. maxima diagnosis have been a common topic of discussion with broiler integrators and their veterinarians. S t U A r t A n d r e w S, P h d For example, he says, the definition of a score 1 for E. maxima with the traditional method is the presence of small red petechiae the spots caused by ruptured blood vessels that may appear on the serosal side of the mid-intestine. There is no ballooning or thickening of the intestine, though small amounts of orange mucus may be present. For an E. maxima lesion score of 2, the serosal surface may be speckled with numerous red petechiae, the intestine may be filled with orange mucus and there is little or no intestinal ballooning; there is thickening of the wall. m o d i F i e d m e t h o d If no endogenous stages such as gametocytes or oocysts are observed, the bird is scored negative for E. maxima, even if small red petechiae are seen, he says. To test the traditional system against their modified version, Andrews and colleagues first followed the traditional procedure when small red petechiae were detected. Then, in a departure from normal procedure, they took fresh mucosal scrapings from close to the yolk-sac diverticulum when any bird had either significant fluid or orange or pinkish mucus in the intestinal lumen or if the birds had intestinal wall ballooning even if no small red petechiae were seen on the serosal surface. With the traditional method for E. maxima detection, diagnosticians take scrapings of the mucosa only when petechiae are present in the mid-intestine. They then use a microscope at 100X magnification to look for the endogenous stages of E. maxima, such as gametocytes or the typical yellowish brown oocysts of E. maxima, Andrews says. The results were quite revealing, he says. Of 108 birds from 18 broiler farms that were evaluated using the traditional method, only six had small red petechiae, and of these, only two 33% were positive for E. maxima. In other words, only 1.9% of all 108 birds examined using the traditional system were positive for E. maxima. 26
3 F i g U r e 1. Percentage of mucosal scrapings positive for endogenous E. maxima based on examination of scrapings despite the absence of small red petechiae on the serosal surface When the researchers used their modified method and also took mid-intestinal scrapings from 42 of 58 birds evaluated, 72% from the same group of 108 were positive for E. maxima. This boosted the E. maxima detection rate to 39% (Figure 1), Andrews says. n o t e A S y t o S e e He points out that the presence of small red petechiae on the serosal surface of the mid-intestine, which is a sign of early stage E. maxima, isn t always easy to see under typical field conditions, even with a magnifying glass, or they may not even be present. In addition, the signs of dysbacteriosis, a commonly seen general imbalance of the normal intestinal flora, are very similar to those of late-stage E. maxima infection (Figure 2). For instance, dysbacteriosis can lead to significant fluid and orange or pinkish mucus in the intestine and intestinal wall ballooning, he says. F i g U r e 2. Significant orange or pinkish mucus in the intestinal lumen can be due to dysbacteriosis or E. maxima. Apart from dysbacteriosis, another source of confusion is the orange or pinkish mucus that can be present in the intestinal tract of birds that have been deprived of feed and water for any length of time, as might occur before thinning or transport. As such, signs of E. maxima infection can easily be overlooked or confused with other conditions, Andrews says. S t r i k i n g d i F F e r e n c e The improvement in detection with the modified method is striking, he says, adding that he and his colleagues now routinely use the modified method for E. maxima detection during posting sessions. Improved diagnosis of E. maxima is especially important considering that coccidiosis remains one of the most economically damaging diseases in chickens and that monitoring the disease relies mainly on lesion scoring, he says. Better diagnosis will, of course, enable more effective coccidiosis-management rotation programs to be developed and, in the long run, will help maintain the economic performance of birds and help secure the long-term future of the anticoccidials they use, Andrews says. Andrews colleagues in the study were Vasil Stanev, DVM; Dieter Vancraeynest, DVM, PhD; and Tony Grainger, all of Zoetis. 27
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3 r e d U c i n g F A l S e P o S i t i v e S PA y S i n e l i S A M Y C O P L A S M A t e S t i n g d i a g N o s t i c s Poultry producers should consider specificity when selecting a Mycoplasma ELISA test to avoid costs associated with false positives, advise researchers at Zoetis Inc. New studies, presented at the 2014 American Association of Avian Pathologists conference, compared the specificity, or the ability to detect true negative samples, of three tests approved for Mycoplasma gallisepticum (MG), M. synoviae (MS) and MG/MS combination testing. 1 In the first two studies, Kit A (ProFLOK MG/MS) was significantly more specific (p 0.05), meaning it yielded fewer false positives, than another commercial ELISA assay for MG/MS testing, Kit B. Positive tests were confirmed using hemagglutination inhibition (HI). The third study compared the specificity of Kits A, B and a third commercial ELISA test, Kit C, to HI. For MG, there were no significant differences between Kits A, B and C. There were also no significant differences for MS between Kit A and Kit C, but both were significantly more specific (p 0.05) than Kit B. For MG/MS combination screening, Kits A and B were significantly more specific (p 0.05) than Kit C (for detailed results, see Table 1). These differences in specificity have meaningful economic consequences for producers, says Dan Domingo, DVM, global director of diagnostic medicine for poultry at Zoetis. For each positive sample, separate HI assays must be performed. At this particular lab, HI tests cost $1 or $2 each, he says. Multiply that cost by the number of false positives for each test per year and we re looking at a substantial economic difference. 1 Zedek, a et al. Comparison of Commercially available mycoplasma Kit (abstract). Proceedings of the annual conference of the american association of avian Pathologists, 2014; 21-22. t A B l e 1. Specificity of three commercial Mycoplasma elisa kits compared to hi kit A (ProFlok mg) kit B mg e l i S A n e g At i v e S A m P l e S 611 608 elisa PoSitive SAmPleS 1 (0.16%) 8 (1.29%) SPeciFicit y 99.84 a 98.70 a kit c mg 614 3 (0.49%) 99.51 a kit A (ProFlok ms) 696 6 (0.86%) 99.15 a kit B ms 489 217 (30.74%) 69.26 b kit c ms 701 5 (0.71%) 99.29 a kit A (ProFlok mg/ms) 612 2 (0.33%) 99.67 a kit B mg/ms 615 2 (0.32%) 99.68 a kit c mg/ms 600 17 (2.75%) 97.24 b different superscript letters indicate a significant difference (p 0.05). 28
I N N O V A T I O N S A N D P R A C T I C A L A D V I C E F O R S U C C E S S F U L F L O C K C A R E POULTRY H E A L T H T ODAY N o w o N l i N e Poultry Health Today s redesigned website features even more news and information to help optimize the health and performance of your birds. Here s a sampling: p o u l t r y h e a l t h t o d a y. c o m EXPERT ADVICE Infectious bronchitis virus: New variants, cross-protection and control Infectious bronchitis (IB) is extremely difficult to manage because different types of the virus causing the disease do not cross-protect, says Mark Jackwood, PhD, an IB authority at the University of Georgia. Practical programs for achieving sustainable coccidiosis control As long as chickens are raised on litter, coccidiosis will remain a threat to the poultry industry, according to H. David Chapman, PhD, a coccidiosis specialist at the University of Arkansas. EDUCATING CUSToMERS Facing poultry s consumer trust challenge If we thought we just needed to tell consumers the answers to certain questions and they would get it, we are wrong, says Bruce Stewart-Brown, DVM, Perdue Farms. He joined four other panelists for a webinar discussion hosted by Watt Global Media and sponsored by Zoetis. HoUSING British vets question health, welfare of free-range chickens While activists tout the happier, healthier life of free-range chickens, veterinarians in Great Britain have expressed concern about the practice s safety and long-term sustainability. VIDEo Kinky back takes costly toll on broilers at 4 to 6 weeks Broiler producers should watch for signs of kinky back, an emerging bacterial disease that often leads to lameness and dehydration, says Drew Parker, DVM, Zoetis. Poultry disease prevention checklist Dr. Casey Ritz of the University of Georgia presents a checklist for poultry farmers to assess the biosecurity risk on their farm. 30
3 The animal doctor s dilemma t h e l a s t w o r d When you become a doctor of veterinary medicine, you take an oath to use your scientific knowledge and skills for the protection of animal health and welfare, [and] the prevention and relief of animal suffering. You also pledge to promote the advancement of medical knowledge and to uphold the principles of veterinary medical ethics. These are high standards, with no room for compromise. Yet today, some poultry veterinarians are being asked to avoid using antibiotics that have been reviewed, approved and licensed for use in poultry and other species by the US Food and Drug Administration. There s nothing wrong with these antibiotics. In fact, most are used strictly in animal medicine and not considered medically important to humans by FDA. Furthermore, many come with strict withdrawal times to prevent antibiotic residues from entering the food chain. Marketing, not medicine Even so, some veterinarians are now having antibiotics pulled from their tool chests not by regulatory agencies but by others in the food chain who think no antibiotics ever has a nice ring to it. Is it right or even ethical to ask veterinarians to avoid using FDA-approved antibiotics solely for marketing reasons? I don t think so. In fact, the American Veterinary Medical Association s Principles of Veterinary Medical Ethics clearly note, The choice of treatments or animal care should not be influenced by considerations other than the needs of the patient, the welfare of the client, and the safety of the public. The same AVMA document goes on to say, The medical judgments of veterinarians should not be influenced by contracts or agreements made by their associations or societies. Trusting veterinarians I have clients who raise broilers without antibiotics, but their costs are higher and, more importantly, fewer chickens get marketed due to poor health and higher mortality. To me, both outcomes are needless because the industry has proved it knows how to use antibiotics safely and judiciously. The bottom line is this: If you don t need antibiotics to address a certain health issue, then by all means, don t use them. Any veterinarian would agree with that. But to deliberately discourage the use of FDA-approved antibiotics solely for marketing purposes undermines the expertise and authority of the veterinary medical profession. As noted before, veterinarians take an oath to advance medical knowledge. It s therefore up to us to educate our non-veterinary colleagues and customers not just about the importance of antibiotics but also the importance of keeping all medical decisions in our hands. LLOYD KECK, DVM Technical Services Veterinarian, Zoetis Inc. lloyd.keck@zoetis.com POULTRY H E A L T H T ODAY Poultry Health Today is published by Pr works and sponsored by the US Poultry Business of Zoetis Inc. articles, comments and any other materials available through Poultry Health Today and its site do not reflect the opinions or analysis of the sponsor. Information available in this publication or on the site does not and should not be relied upon to replace the advice of your own animal-health advisors or the indications or safety precautions stated on product labels. Please send editorial comments and story ideas to editor@poultryhealthtoday.com. For subscriptions, go to poultryhealthtoday.com/subscribe. editor: JoSePh FeekS Managing editor: diana delmar News editors: MeGhaN FeekS, NataLIe knudsen digital editor: SUSaN SPIeGeL web engineer: JeSSe JeNIFer art director: SUSaNNa ronner Proofreader: ruth MISIewIcZ copyright, 2014. articles may be reprinted with written permission of the editor. Printed on recycled paper Sponsored by p o u l t r y h e a l t h t o d a y. c o m 31