Ear, tail and skin lesions vary according to production flow

The new study is authored by Alessia Diana, Laura Ann Boyle, Edgar García Manzanilla, Finola Catherine Leonard and Julia Adriana Calderón Díaz from the Teagasc Animal and Grassland Research and Innovation Centre, Cork, and the School of Veterinary Medicine at the University College Dublin.

The study investigated the association between production flow and tail, ear and skin lesions on a farm with an ‘all-in/all-out’ policy. The study was purely observational meaning pigs were managed according to routine farm practice – no treatment was administered and there were no changes to husbandry as part of the investigation.

A total of 1,016 pigs born within 1 week from the same batch were followed through the production stages and the presence or absence of welfare indicators was recorded at 4, 7, 9, 12, 16 and 24 weeks of age.

Three production flows were retrospectively identified:

  • flow one = ‘normal’ pigs that advanced through the production stages together ‘on time’;
  • flow two = pigs delayed from advancing from the 1st to the 2nd nursery stage by 1 week; and
  • flow three = pigs delayed from advancing through the production stages by > 1 week.

The trial results show:

  • The presence of ear lesions was highest in pigs in flow one, with pigs in flow two 4.5 times less likely to have ear lesions compared to flow one.
  • Pigs in flow one and flow three were more likely to have tail lesions compared to flow two.
  • The risk of skin lesions being present was dictated mostly by pig age in each production flow.

The study concluded that all production flows were associated with a high risk of lesions to ears, tails and skin, which raises concerns for pig welfare. Risks for lesions varied according to each production flow and the researchers believe this is likely due to the specific management practices inherent to each flow.

Read the full article here.

Replacement gilts and neonatal diarrhoea

The influence of replacement gilts on the severity or frequency of neonatal diarrhoea is not entirely clear, but farmers know that they have more problems in litters from first parity sows.

This has been shown by different studies: one study carried out in Sweden resulted in 81 percent of the farmers saying, when questioned, that the problem of neonatal diarrhoea was more common in first parity sow litters1. Other studies reported a higher presence of neonatal diarrhoea amongst first and second parity sow litters2.

Gilts tend to have a lower colostrum IgG content than other parity sows3, which could explain why their piglets are more prone to suffering diarrhoea. In fact, when the serum IgG concentrations of piglets affected by diarrhoea are compared with those of healthy piglets, those affected always have lower concentrations2.

© Sialelli et al, 2009

The correct management of replacement gilts will therefore be one of the points to be taken into account when monitoring this type of process. In order to reduce the risk of neonatal diarrhoea, the ideal would be not to have first parity sows, but we know that this is not possible, as sooner or later we have to replace the stock, so that constant renewal is preferable, whilst at the same time trying to work with the lowest percentage possible.

A farm’s gilt replacement rate depends on two factors:

  1. The maximum parity for culling.
  2. Involuntary culling (sows that are sent to slaughter before they have reached maximum parity).

The maximum parity of sows is based on the cost of production of their piglets. Although there are differences from one farm to another, it is generally considered that after parity 6, sows start to produce more expensive piglets and this is absolutely clear after parity 8. It is therefore common to establish parity 8 as the maximum parity, or even earlier on very strict farms: parity 7 or 6. As regards involuntary culling, this will depend on different factors:

  • Management of the gilt (age at first mating).
  • Health acclimatisation.
  • Reproductive management.

The better the management of the sows, and in particular the management of replacement gilts, the greater the retention rate will be and hence the lower the involuntary culling rate will be. When we looked at the data from different farms, we found that the average involuntary culling rate (average culling between different parities) is approximately 15 percent. Which means that the annual gilt replacement rate that is necessary to keep a constant number of sows on a farm with an average involuntary culling rate of 15 percent, and where the maximum parity for culling is parity 8, is about 50 percent. This means that in each group of sows mated (batch), the percentage of gilts will be approximately 20 percent, or what is the same thing, of the sows present on a farm, approximately 20 percent will be parity 1 sows (from first mating to post first-weaning).

Reducing the gilt replacement rate should never be done by extending the maximum parity for culling, but by reducing the involuntary culling of sows. For this it is essential to apply proper management and nutrition which should take account of the following points at least:

  1. Selection of a reliable source of replacement, with a health status that is superior or equal to that of the recipient farm.
  2. Regular introduction or production such that the policy of culling sows at maximum parity is not compromised.
  3. Proper adaptation by means of an appropriate vaccination plan that must include vaccination against the principal pathogens implicated in neonatal diarrhoea: E. coli and Cl. perfringens; and exposure to the pathogens present on the recipient farm. In order to achieve appropriate health acclimatisation, it is important to have separate units and sufficient space where the animals can be kept for at least 8 -12 weeks.
  4. Mating at the appropriate age for the genetics selected. But always prioritising their retention on the farm: mating at over 240 days of age and weight of over 140 kg.
  5. We should not forget that the nutrition of a gilt up to the first mating will be vital to enable her to develop her full potential for growth in a balanced way, paying special attention to mineral intake, as the soundness of her leg conformation will depend on this to a large extent.

The management of replacement gilts should be regarded as the greatest influence on the resultant output of a farm, but also on the manifestation of health problems, and neonatal diarrhoea is perhaps the most widespread problem on all types of farm, from those with a high health status to commercial ones.

Why is PRRS virus so genetically diverse?

A better understanding of the natural history of PRRSV can provide insights that can potentially aid in mitigating the impact of the emergence of new viral variants.

Porcine reproductive and respiratory syndrome virus, the etiological agent of PRRS, is one of the most important endemic viruses affecting the swine industry in the United States1and globally2. The economic impact of the disease in the United States alone was estimated at $664 million annually1.

PRRSV is divided into two major phylogenetic clades, PRRSV Type 1 (more prevalent in Europe) and Type 2 (more prevalent in North America)3. Genetic similarities between PRRSV isolates are often used as a tool to understand disease transmission and epidemiology4,5, and several strategies have been used for classifying isolates of PRRSV into epidemiologically meaningful groups. Restriction Fragment Length Polymorphism, commonly referred to as “RFLPs”, have been broadly adopted by the U.S. swine industry as a way to classify PRRSV isolates. However, shortcomings such as the unclear genetic relationship between RFLP types, the potential for two distantly related viruses to share the same RFLP type, and the instability of RFLP-typing when assessing isolates experimentally related to each other6 hinder interpretation of RFLP types.

In 2010, a classification system based on the phylogenetic relatedness of one portion of the PRRSV genome known as the open reading frame 5 (orf5) was proposed7,8. This classification system aggregates isolates into phylogenetic lineages based on the ancestral relationships and genetic distance among isolates. These lineages can be thought of as “ancestral families.” As compared to RFLPs, the relatedness among lineages are more intuitive and evolutionary trends across space and time can be tracked more easily. There are nine lineages known for PRRSV Type 2, each of which are approximately 11% different from one another in the average pairwise genetic distance7.

Despite control efforts involving improved biosecurity and different vaccination and exposure protocols, PRRSV continues to circulate and evolve. High levels of genetic and antigenic diversity are one of the foremost challenges in its control. Prior exposure to PRRS viruses results in varying protection against homologous and heterologous challenges, albeit the exact definition of what constitutes a homologous or heterologous challenge is often not clear, especially considering the genetic diversity existing within PRRSV Type 2.

Using more than 4,000 PRRSV orf5 sequences collected from 2009-17 from a single U.S. region curated by the University of Minnesota’s Morrison Swine Health Monitoring Project, we investigated how the occurrence of different lineages of PRRSV changed through time. We were able to document the sequential emergence of several PRRSV sub-lineages, including a sub-lineage containing most 1-7-4 viruses, which rapidly grew in prevalence to the point in which they were the most prevalent phylogenetic group occurring in the studied area at a given time. These emergence events appeared to occur every four or five years. Our group continues to analyze data to further understand

The diversification and temporal dynamics of PRRSV observed in our dataset is consistent with the hypothesis that PRRSV long-term evolutionary patterns are at least partially modulated by immune-mediated selection. Veterinarians in farms might choose to expose their breeding herds and incoming gilts to different PRRS viruses (either from different vaccines or from wild viruses isolated on each farm). These practices combined with relatively high prevalence of immunity resulting from natural exposure likely create pig populations with high rates of PRRSV immunity, even if cross-protection is only partial. While high levels of herd immunity potentially diminish the odds or severity of future outbreaks due to “homologous” viruses, we hypothesize that partial immunity may also create selective pressure that might select for viruses that can “escape” or evade host immunity. As a virus evolves, immune responses generated against a past variant become less effective, resulting in a complex system where different PRRSV variants influence one another via the partial cross-immunity that they generate in the host population9,10. Theory predicts that due to frequency-dependent selection among co-circulating viral variants, rare genetic variants are expected to spread more widely in the host population but then subsequently decline as herd immunity rises.

This has important implications in identifying patterns of emergence and re-emergence of genetic variants of PRRSV that have negative impacts on the swine industry. Although the data analyzed here come from a single U.S. region, the general pattern of emergence and turnover of different lineages over time reflect an evolutionary phenomenon that should also occur in other U.S. regions. A better understanding of the natural history of PRRSV can provide insights that can potentially aid in mitigating the impact of the emergence of new viral variants as well as serving as a basis for further work exploring the evolution of PRRSV and the effect this has on disease control, management and impact on the industry. To that end, constant surveillance on PRRSV occurrence is crucial. Further studies utilizing whole genome sequencing and exploring the extent of cross-immunity between heterologous PRRS viruses could shed light on immunological response against PRRSV and aid in developing strategies that might be able to diminish disease impact.

pigs at a feeder National Pork Board First five mitigants show promise protecting pigs from PRRS, PED, SVA

A separate FFAR-funded grant at Kansas State University will build on this research to test whether the additives can be added to feed to protect against African swine fever.

Initial results from a study conducted by Pipestone Applied Research have shown that five commercially available feed additives may stop the spread of three deadly viral diseases in pigs. Scott Dee, research director at Pipestone Applied Research, presented the results of the first phase of the study, supported through a Foundation for Food and Agriculture Research grant, during the National Pork Industry Conference in the Wisconsin Dells this week.

Porcine reproductive and respiratory syndrome, porcine epidemic diarrhea and Seneca Valley A endanger animal welfare, cost the U.S. swine industry hundreds of millions of dollars annually and threaten the global food supply. These diseases can also spread through contaminated animal feed.

In this study, the Pipestone team tested whether specific feed additives, or mitigants, can deactivate the viruses and reduce the spread of disease. Researchers introduced the three viruses into animal feed and then individually added five mitigants to the contaminated animal feed. The research team then tested the pigs at day 6 and day 15 for the presence of the three viruses and evaluated the animals for signs of disease. Despite the presence of PRRS, PED and SVA viruses in the feed, the mitigants protected almost all animals from becoming positive for infection by PRRS, PED and SVA and significantly reduced the number of animals that developed signs of disease.

This study is one of the first to produce results in a research setting that replicates commercial conditions. Dee and collaborators suggest that pork producers consider using these mitigants to protect herds against these diseases.

“These results are a huge step forward in helping swine producers protect their animals from devastating diseases,” says FFAR executive director Sally Rockey. “This research helps producers control the spread of these diseases and improve health outcomes, all without antibiotics.”

Later this year, a second phase of the research will test five additional mitigants to assess their effectiveness in protecting swine herds from PRRS, PED and SVA. A separate FFAR-funded grant at Kansas State University will build on this research to test whether the mitigants can be added to feed to protect against African swine fever, a disease without a cure, which has decimated the Chinese pork industry and was recently detected in Europe. ASF virus can cross continents in contaminated feed ingredients. Scientists hope to understand how to control, or even stop the spread of this deadly virus.

“Pipestone Applied Research is excited to collaborate with FFAR. We are working to deliver a solution to the risk of the domestic and transboundary spread of viruses in feed,” says Dee.

Dee’s team received a grant through FFAR’s Rapid Outcomes from Agricultural Research program, which deploys funds research funding in response to emerging or unanticipated threats to the nation’s food supply or agricultural systems. The grant is being matched by ADM Animal Nutrition, Anitox, Kemin Industries, PMI Nutrition Additives and Swine Health Information Center.

Enhancing DDGS value for pigs via pre-treatment, pre-digestion

Heat pretreatment can be an attractive method of improving the digestibility of whole stillage, and hence DDGS, for pigs because heat pretreatment is cheap.

Corn distiller’s dried grains with solubles is one of the most widely used feedstuff in formulating swine diets. Corn DDGS has a higher content of amino acids than corn, however, it also has a high fiber content. Since pigs digest fiber poorly, the use of dietary fiber degrading enzymes has been shown to alleviate the negative effects of dietary fiber. However, the use of exogenous enzyme supplementation has been variable with respect to improving the digestibility of DDGS for pigs.

Pretreatment of whole stillage (slurry material that remains after ethanol extraction from grain, and which is dried into DDGS) with heat, diluted acids or alkalis may improve the nutritive value of DDGS by disrupting fiber structures, thereby increasing the susceptibility of said fiber fraction to subsequent enzymatic hydrolysis. Thus, the pretreatment of WS instead of DDGS could be an attractive technology for improving the nutritive value of DDGS as this technology can be integrated into currently existing corn ethanol production facilities with minimal cost.

Recent research at South Dakota State University looked at the effect of pretreating WS with heat, diluted acids or alkalis; and of predigesting the untreated and pretreated WS with a blend of fiber-degrading enzymes (multi-enzyme) on digestion and fermentation characteristics of the WS using an in vitro (laboratory) porcine method that simulates digestion and fermentation of feed within the gastrointestinal tract of pigs.

South Dakota State UniversityTable 1. Effect of pretreatment and multi-enzyme pre-digestion on total content of fiber (non-starch polysaccharide; NSP) and individual sugars that form NSP of whole stillage,  and proportions of sugars that were released from the NSP

Effect of pretreatment and multi-enzyme pre-digestion on total content of fiber

The WS was obtained from a local ethanol plant. A portion of the WS was pretreated with heat, diluted citric acid, diluted sulfuric acid or diluted ammonia at 160 degrees C and 70 psi for 20 minutes. Half amounts of untreated and pretreated WS were predigested with multi-enzyme (1%) at 38 degrees C for 24 hours. The multi-enzyme used was from Canadian Bio-Systems Inc. in Calgary, Alberta, Canada, and contained a combination of xylanase, glucanase, cellulase, invertase, amylase, mannanase and protease activities. The predigested samples together with untreated sample and pretreated but not predigested samples were subjected to porcine in vitro digestion. Undigested residues were subjected to porcine in vitro fermentation.

South Dakota State University In-vitro digestibility of DM of pretreated and pre-digested whole stillage

In-vitro digestibility of DM of pretreated and pre-digested whole stillage

The pre-treatment of WS with heat, diluted citric acid, diluted sulfuric acid or diluted ammonia reduced fiber content by 10, 46, 20 and 23%, respectively. The reduction in fiber content of WS by the pretreatments was due to partial degradation of fiber into short fragments that can be easily fermented or into simple sugars that can be easily digested by pigs. Predigestion of untreated or pretreated WS with multi-enzyme reduced its fiber content by an average of 37%, which was due to the partial degradation of fiber within WS by the multi-enzyme. Pretreatment of WS with heat, diluted citric acid, diluted sulfuric acid or diluted ammonia increased in vitro digestibility of WS by an average of 17%, which could partly have been due to increased digestibility of sugars that were released from fiber by the pretreatments. Also, multi-enzyme predigestion of untreated and heat-, citric acid-, sulfuric acid- or ammonia-pretreated WS increased in vitro digestibility of WS by an average of 14%, likely due to increased digestibility of sugars that were released by the predigestion with the multi-enzyme.

In summary, the nutritive value of WS, and hence DDGS, for pigs can be improved by the pretreatment with heat, diluted citric acid, diluted sulfuric acid or diluted ammonia. However, heat pretreatment can be an attractive method of improving the digestibility of WS, and hence DDGS, for pigs because heat pretreatment is cheap. The nutritive value of WS, and hence DDGS, for pigs can also be improved by predigestion with multi-enzyme product used in the current study. Predigestion of pretreated WS with multi-enzyme product used in the current study can further improve nutritive value of the WS, and hence DDGS, for pigs.

Frequently asked questions about erysipelas

For the chronic form of swine erysipelas, clinical presentation includes swollen joints, sloughing of the discolored skin and growths on the valves inside the heart.

Swine erysipelas is a disease caused by a bacterial infection named Erysipelothrix rhusiopathiae. It has been around for well over 100 years. It is important to remember that this bacterium can cause disease within your breeding herd, as well as your growing pigs. Although the prevalence is low in the industry, it can have significant impact on your production, health and on the bottom line of your operation.

VanderPoel graduated from South Dakota State University with a degree in animal science, and then pursued his DVM degree at the University of Minnesota. He currently works as a swine veterinarian for Pipestone Veterinary Services and Pipestone System.

What are the symptoms?
This disease can be present either in an acute or chronic form. There is no clear distinction between the two forms, but please note for population health there may be animals in different stages of disease within your herd. The clinical presentation for swine erysipelas in the acute form can be sudden death, lethargy, high fevers, severe lameness and abortions. These sick animals often have reddened discoloration of the skin, and in the classic cases the animals will show raised diamond-shape lesions in the skin.

How can I prevent erysipelas?

For the chronic form of swine erysipelas, clinical presentation includes swollen joints, sloughing of the discolored skin and growths on the valves inside the heart. I was taught in school never to describe disease lesions with food descriptors. However, for producers willing to post their pigs, it is easiest to describe as a cauliflower growth on the inside of the heart.

No matter which form of this disease may be presented, it is very important that you detect this disease as early as possible because treatment of this disease has a high rate of success. However, due to a significant withdrawal period on the treatment of choice, and the success of the vaccine, the overall long-term goal should be to stabilize and prevent disease through vaccination of your herd.

Like previously mentioned, vaccines can be very effective tools we have to control this disease. It can be administered either orally or as an injectable vaccine and that would depend on factors specific to your operations such as cost, labor, medication management or equipment. For the sow populations, I always recommend that vaccine is given at least twice per year as risk management of your sow farm and downstream health. As for the growing animals, there are multiple approaches; all groups receive vaccine or a seasonal approach where you only vaccinate to protect animals during the summer months. This latter vaccination strategy is due to a cost benefit analysis and seasonal disease pattern where it can be more prevalent in the summer months. Whatever your strategy may be, I would encourage you to have an overall goal to control this disease and prevent it from infecting other pigs.

How does it spread?
Swine erysipelas is spread when infected pigs shed these bacteria at high levels in their feces and contaminate their environment. Other pigs become infected when they ingest the infected feed, water or feces, as well as have direct nose to nose contact with infected animals. Like many diseases, to reduce the risk of spreading this disease between barns you will need to have strict biosecurity protocols, thorough sanitation and disinfection protocols, all in/all out site or room practices when able, vaccinate and timely medication when needed.

If you are struggling on your operation with any of the clinical symptoms previously mentioned or are seeing the classic diamond-shaped lesions, work with your veterinarian to develop a plan to identify and stabilize your herd from this disease. Again, when it comes to swine erysipelas and the long-term success of your operation, you can control and prevent this disease through strict biosecurity, hygiene protocols, vaccination and medication when needed.

Genetics of swine functional teats

The number of functional teats can be estimated prior to farrowing or quantified at farrowing.

By Audrey Earnhardt and Mark Knauer, North Carolina State University
Piglet survival is of great importance for swine producers throughout the world due to its relationship with animal well-being and farm profitability. Recent data in the United States indicate piglet survival has perhaps decreased as litter size has increased (Figure 1). Yet production systems and geneticists alike are working fervently to reduce this trend.

North Carolina State UniversityFigure 1: U.S. trends for total number born, number weaned and piglet survival.

Figure 1: U.S. trends for total number born, number weaned and piglet survival.

 

Availability and accessibility of functional teats on a sow is essential for enhancing piglet livability. Yet this has been known for some time. In 1961, Enfield and Rempel reported an increase in one functional teat improved number weaned by 0.27 piglets per litter and litter weaning weight by 11.7 pounds per litter.

Building upon these results, North Carolina State University partnered with Smithfield Premium Genetics to evaluate the genetics and importance of functional teats in a modern genetic line. Teats from over 3,000 sows were classified as functional or non-functional. Total teats, functional teats and non-functional teats at farrowing for the population were 14.93, 13.90 and 1.03, respectively. Similar to Enfield and Rempel (1961), our results showed each additional functional teat at farrowing increased number weaned by 0.27 piglets per litter.

Heritability estimates the proportion of a trait that is explained by genetics. For example, if the heritability of a trait is 0.25 then genetics are thought to explain 25% of the variation in that trait with the remaining 75% being explained by environmental factors. Generally, heritability estimates for litter size in swine are low (~0.10), growth rate is moderate (~0.20) and age at puberty high (~0.30). The greater the heritability, the faster genetic progress can be obtained.

In our current study, estimates of heritability for total teats, functional teats and non-functional teats at farrowing were 0.26, 0.22 and 0.12, respectively. Hence functional teat number was moderately heritable.

Summary

  • Results suggest
    • It is possible to increase the number of functional teats on a sow at farrowing.
    • Increasing the number of functional teats at farrowing will enhance piglet survival.
  • We recommend cross-fostering based on the number of functional teats a sow has. The number of functional teats can be estimated prior to farrowing or quantified at farrowing and written on the sow to aid workers when cross-fostering.

TREATMENT AND CONTROL OF SWINE RESPIRATORY DISEASE

Introduction

Respiratory disease in swine, despite the exponential adoption of All-In/All-Out production within United States and Canada, remains a major constraint to profitability. Today I would like to describe some of the control and treatment methods available in a disease outbreak. To control and treat disease we should understand the pig’s protection mechanisms against respiratory pathogens and how this mechanism is broken down by contributing factors of respiratory disease. Through our discussion, we will understand how environmental and management practices are the most consistent means of control against repiratory disease.

Protective Mechanisms

The pig’s protection mechanism consist of both physical and cellular barriers which prevent entry of infectious agents or destroy the agents that have come in contact with the pig. Nasal airways and the mucociliary apparatus are two physical barriers. The nasal passage provides a physical barrier to particles greater than 5 um in diameter and smaller particles are handled by a mucociliary clearance apparatus. This apparatus is composed of fine hair-like structures which move the particles back up toward the mouth of the pig where the particles are then swallowed. Within the lung there exists a cellular defense mechanism called pulmonary macrophage cells. Macrophage cells act to neutralize pathogens (bacteria or virus). If this is not effective then the macrophage will recruit another cell-type, neutrophils, to remove debris and pathogens. Antibodies and T-cell production are triggered by the presence of pathogens. An immune animal is one which has previous exposure via natural infection or vaccination. A nonimmune animal is one that has no previous exposure to the pathogen. Maternal antibodies or passive immunity is the protection that piglets receive from drinking the sow’s colostrum. While the sow continues to be a major reservoir of pathogens, maternal antibodies transferred to the piglets prevents pathogens from penetrating the piglet’s system. Maternal antibodies tend to breakdown near the time the piglet is developing it’s own antibodies. Therefore there is a period at 3-5 weeks of age when the piglet has low levels of protection.

Transmission of Disease: 2 Primary Mechanisms

1) Pig to Pig: The nose, mouth and trachea is a habitat for many organisms. Organisms which do not promote an immune response are called commensal. Conversely, organisms which release toxins, destroy tissue or lower the immune system are deemed pathogens. Commensal organisms such as Haemophilus parasuis (Hpp) and Streptococcus suis (Strep. suis) can thrive when piglets are exposed while protected by maternal antibodies, without clinical signs of disease. However, nonimmune pigs (SPF or SEW pigs), not previously exposed to Hpp and Strep. suis may result in severe respiratory disease in the presence of primary pathogens.

2) Airborne Transmission: Organisms such as M. hyopneumonia (MH), Porcine Respiratory Coronavirus (PRCV), Swine Influenza Virus (SIV), and Pseudorabies virus (PRV) are capable of airborne transmission up to several kilometers in distance. Airborne spread is facilitated by prevailing wind velocity and direction, cloud cover and humidity.

Predisposing factors for Increased Risk of Respiratory Disease

  • Management systems which do not employ all in all out
  • Large number of pigs with large variation in age in one barn or air space
  • Frequent moving and sorting of pigs through the barn
  • Positive disease status of replacement or supplemental stock
  • Overcrowding and increased pen density
  • Changing weather patterns creating stressful conditions especially in outdoor or nonmechanical ventilation systems. During the winter months there is less air exchange.

Control Strategies

There are two primary goals to disease prevention:

Goal # 1) minimize the “dose” or number of pathogens to pigs by;

  • matching health status
  • reducing number of sources
  • early (between 14 and 21 days) and segregated weaning
  • proper ventilation and contaminant removal
  • maintain acceptable pig density

Goal # 2) to interrupt the natural build-up of pathogens within the pigs environment;

  • good hygiene
  • utilizing All-In/All-Out
  • partial depopulation
  • multi-site production

Treatment and Control of Disease

Management Strategies

  • Ensure adequate air flow from a fresh source, especially in the winter months. pre-warmed but not from a communal air chamber.
  • Reduce fluctuations in temperature and high humidity within the pig space
  • RH at 50 70%
  • Provide proper stocking density.
  • Provide All-In/All-Out from farrowing to finishing. No more than 3 weeks age variation per air space will reduce disease and improve growth performance.
  • Isolate all incoming replacements stock for at least 30 days prior to introduction to the rest of the herd. Introduce larger groups of replacements less frequently and avoid outside replacements if economical.

Actinobacillus pleuropneumonia (App)

Subclinical carriers of App are the primary cause of outbreaks. Serology (30 samples) from pigs at 7-8 weeks of age is important to determine if App carriers are present, isolate App serotype, and determine sensitivity to antibiotics. Positive results from serology taken from 7-8 week old pigs denotes; a recent infection, presence of carriers, and an active infection in the herd.

1) IF your herd is Positive on serology but negative for clinical signs.

Use serology to measure presence of other pathogens which are contributing factors such as PRRS, M. hyo, salmonellosis, and atrophic rhinitis.

2) IF your herd is Positive on serology and positive for clinical signs.

Use serology to measure presence of other pathogens which are contributing factors such as PRRS, M. hyo, salmonellosis, and atrophic rhinitis.

Antibiotics: Injection of pigs as soon as they show clinical signs of anorexia, breathing difficulty and depression (dog sitting). Sick pigs should be injected twice a day for as long as they are sick. Compliance is difficult because this is labor intensive, time consuming and expensive. Mass medication using drinking water medication may be useful. Feed additive antibiotics are of little value against App because pigs are generally not eating and the minimum levels of antibiotic required in the blood to kill the organism is not attainable via feed grade regardless of dosage levels. Besides, feeding pigs at rates above the licensed levels is illegal.

Vaccination:Current vaccines do not reliably prevent pleuropneumonia but MAY reduce mortality rate if the vaccine serotype matches that of the serotype on your farm. Vaccine serotypes do not provide crossprotection against other serotypes. Vaccination of sows may reduce piglet protection by colostral immunity.

Replacement stock must be App negative. Serology on entry and again 30 days later.

Full or partial depopulation: Full: Cost effective when 30% + of unvaccinated sows are App positive.

Eradication: Not an effective method. Many eradication efforts fail. Takes about one year. Must empty the weaner and finishing facility in a farrow to finish operation. Test and cull sows which are positive for App.

Lung lesions resolve in 1-2 months, therefore slaughter checks may not be indicative of App.

3) IF your herd is Negative for clinical signs and negative on serology.

Ensure that breeding stock from supplier is negative and remains negative.

Question if App vaccine is used in gilts prior to entry

Serological Monitoring using ELISA tests for App.

Mycoplasma hyopneumoniae (M. hyo)

Transmission is primarily from pig to pig although long range aerosol transmission is possible. M. Hyo has been isolated from lungs of clinically normal pigs. Based on serology surveys, nearly all commercial swine herds have M. hyo. Clinical signs within the herd (coughing, depression and poor growth rate) are dependent on the dose of infection, contributing pathogens and environmental stress. Many producers are utilizing All-In/All-Out for the farrowing and nursery units. Therefore pigs are not affected until the finishing units when pigs of various ages are exposed to M. hyo carriers.

Antibiotics: Many antibiotics are shown to be effective in a laboratory setting but the effectiveness is questionable in the herd. While antibiotics may improve growth performance during administration, once the antibiotic has been removed, clinical signs and poor growth performance resume.

Vaccination: Commercial vaccines are available and tend to reduce to severity of clinical signs (i.e. coughing) but have not always demonstrated an advantage in growth rate.

Atrophic Rhinitis (AR)

The severe and progressive form is caused by a combination of two bacteria: Bordetella bronchiseptica and Pasteurella multocidaB. bronchiseptica lines the mucosa of the nasal passage allowing the adherence of toxin producing P. multocida which destroys the nasal cavity and turbinates. Some transmission of bacteria is from the sow to the piglet, but transmission after 3 weeks of age is generally from one pig to another via droplets.

Antibiotics: First and foremost, proper testing is required to determine drug sensitivity of the bacteria. Antibiotics such as oxytetracylines and sulfonamides can be used in feed medication in the last month of gestation to control the shedding of bacteria from sows to her subsequent litter. Injectable oxytetracyclines and potentiated sulphonamides (under a veterinary/client relationship) are often used under a program for piglets which consists of three to four injections in the first 21-28 days of life.

Vaccination: The vaccination program is targeted to protect piglets before infection. Vaccinate sows (prefarrow) with a vaccine containing the appropriate P. multocidatoxin. Vaccination of piglets must be performed 2 weeks prior to natural exposure of the bacteria.

Salmonella cholerasuis: S. cholerasuis is a species specific organism transmitted by feces from clinically infected or carrier pigs. Diagnosis is based on clinical signs, necropsy, bacterial culture and histology results.

Antibiotics: Injectable antibiotics provide the most effective treatment in outbreak infections. Affected pigs may continue to eat and drink, therefore mass medications using appropriate antibiotics in the feed and/or drinking water may reduce death loss.

Porcine Respiratory Disease Complex(PRDC)

Porcine Reproductive and Respiratory Virus (PRRS), Swine Influenza Virus, Porcine Respiratory Coronavirus, and Pseudorabies.

Respiratory disease caused by PRRS, in itself, is infrequent in pigs. Concurrent respiratory infections of PRRS and bacteria are common. Pat Halbur at Iowa State University and David Zeman at South Dakota State University have determined that of the swine respiratory disease cases submitted, greater than 50 percent of the PRRS submissions where complicated with bacterial infections such as P. multocidaStrep. suisHaemophilus parasuis and S. cholerasuis.

PRRS, Mycoplasma hyopneumonia, Swine Influenza Virus and Actinobacillus pleuropneumoniae are the most common primary agents involved in the Porcine Respiratory Disease Complex (PRDC). This complex tends to affect pigs at 18-20 weeks of age. Treatment and control of this complex is based on proper diagnosis using a combination of detailed clinical history, serology and necropsy. Long term control strategies include segregated weaning, All-In/All-Out in each stage of growth, ventilation modifications and biosecurity measures.

Take-Home Message

A poorly managed hog farm with a high incidence of respiratory disease was used in a clinical trial to determine whether use of a particular antibiotic would improve growth performance on this farm. The farm facilities were not large enough to replicate the trial, therefore some of the pigs from this farm were moved to the university farm. The original hog farm was continuous flow and of poor conditions in terms of ventilation, high pig density and inadequate sanitation procedures. The university facility had good sanitation and better management practices. As in the children’s rhyme: some piggies stayed home, while others went off to the university. The pigs at the home farm treated with antibiotics improved in growth performance over the untreated pigs at home. The pigs which went off to university, both the treated and the untreated outperformed the treated stay at home pigs. The moral of the story is that management and environment is the better choice over medication for respiratory disease control. OR Be cool and stay in school.

Most common pig diseases

common pig diseases

Pig producers, just like any other animal farmers are well aware of the fact that in order to be successful in their field, they must ensure the health of their pig stock. Given that prevention is the best measure to avoid losing valuable animals, it’s important to know which are some of the most common pig diseases, their symptoms and treatment methods. It should also be noted how important it is to work with specialists – veterinarians and technicians – to establish a herd health plan to cover the three stages of the pig production (pre-weaning, growing-finishing, and breeding).

Pig diseases in the pre-weaning stage

1. Exudative dermatitis (greasy pig disease)

This disease is caused by an infection with the Staphylococcus hyicus bacteria and it manifests through skin lesions. Mortality can occur due to greasy pig disease in severe cases that are left untreated. The lesions first appear as dark spots on the skin, which spread and become flaky, with a greasy feel.

The infection is treated with antibiotics, skin protectants, and autogenous vaccines. One of the best prevention methods is to improve hygiene conditions in the piglet housing areas. It is also recommended to perform teat dipping on the sows as well as pre- and post-farrowing. By reducing the potential of skin abrasions, the infection is prevented from entering the piglet’s system. Skin abrasions can be caused by rough floors, sharp equipment, jagged teeth or mites’ bites.

2. Coccidiosis

Coccidiosis is very common in suckling pigs, being caused by three types of the coccidia intercellular parasite. The main symptom is diarrhea, which can also be bloody and it occurs during between 10 and 21 days of age and up to 15 weeks of age. Acute cases can be treated with coccidiostats and fluid therapy. Because the intestinal wall can be damaged in some cases, secondary infections may occur.

Sows can be treated with coccidiostats in order to prevent this disease. It’s also good to improve hygiene conditions on the farm, to end the circle of infections. Sow feces are a major source of infections. In addition, flies drawn to the feces can further spread the infection. To prevent the occurrence of parasite infections, it is recommended to maintain a warm, clean and dry creep area on the farm.

pig farm housing

Pig diseases in the post-weaning stage

1. Respiratory diseases

The most common symptoms of respiratory diseases are coughing, sneezing, heavy breathing, reduced growth, and even mortality. To treat this type of diseases, antibiotics are often given in feed or water or as injectable substances. Certain environmental conditions or poor ventilation can worsen respiratory diseases or help spread them. For example, high levels of ammonia found in the environment can damage the respiratory tract and thus making pigs more prune to infections.

Among the infectious agents responsible for the occurrence of respiratory diseases are Streptococcus suis and Pasteurella. Some forms of pneumonia can be prevented through vaccines, but it’s important to identify the strain present on a farm to fight against this disease in an efficient way. Especially pleuropneumonia, caused by Actinobacillus pleuropneumoniae can cause a high mortality rate and the surviving pigs suffer from reduced growth rate and lung damage. Along with the presence of respiratory viruses, overcrowded and dirty housing are predisposing factors for respiratory diseases.

2. Swine dysentery

Pigs that suffer from dysentery have diarrhea, with or without the presence of blood. This disease is caused by the bacteria Brachyspira hyodsenteriae. Pigs that suffer from dysentery in the post-weaning stage have reduced growth rate; in more severe cases sudden death can occur.

Swine dysentery is also treated with antibiotics which are given through feed or water, or as injectable substances. To reduce the infection, it’s recommended to reduce the stock density. Improving hygiene and rodent control can also significantly help prevent and reduce the potential of infection. Rodents are important when it comes to the spreading of swine dysentery. The disease can occur when new stock is introduced on the farm, so it’s important to always buy pigs from reliable sources and to request a thorough medical check-up.

Pig diseases in the breeding stage

1. Mastitis

Mastitis is a disease present in sows and it has symptoms such as reduced milk production, higher body temperature and loss of appetite. The disease is caused by a bacterial infection of the mammary glands, where skin discolorations can be observed. Antibiotics and anti-inflammatory drugs are the most efficient treatment for mastitis. Usually, a combination of oxytocin and corticosteroids is prescribed to treat mastitis.

Like in the case of other pig diseases, improving hygiene in farrowing houses is extremely important. Healthy nutrition during the late pregnancy stage is an important factor to increase immunity. Stress is also considered a factor in the occurrence of mastitis, especially if the teats may suffer damages in the sow housing facilities. Mastitis has an important effect on productivity because the number of piglets weaned by sows can be significantly reduced.

2. Porcine parvovirus

Pregnant sows can become infected with the parvovirus (PVV) and in some cases, reproductive diseases can occur. Usually, the reproductive disease occurs in gilts, the reproductive performance being overall affected. Pig litters are decreased in size because of stillbirths and mummification. The parvovirus is somewhat more difficult to diagnose because other reproductive diseases present similar symptoms. The virus can survive outside its host for several months.

PPV is problematic usually during pregnancies, but other pigs can also spread the disease. As there are no treatments for this disease, prevention is extremely important, through regular vaccination of gilts.

pig farm housing

Other common pig diseases and health problems

1. Malnutrition

This is one of the most common pig diseases, easily recognizable because the animals grow slowly and are visibly thin. In healthy pigs, the only bones that should be visible are the shoulder blades. If farmers can notice the backbone, the hips or the ribs, the pigs are too thin. Pigs have a great advantage of growing rapidly. If they are growing too slowly, it’s most likely because of malnutrition.

Malnutrition occurs because of insufficient or poor quality feed. Growing pigs need more feed and of higher quality than adults. Lactating sows also need more high-quality feed to produce milk; otherwise, they will start to lose weight.

2. Lice and flies

As major factors in the spreading of diseases on pig farms, lice and flies infestations pose a serious health threat. Pig lice are rather large and very easy to spot. They can cause blood loss and the infection with bacteria. Flies can also be a problem because they enter open wounds and cause infections. Both lice and flies can be treated with sprays. Ensuring proper hygiene in the housing areas, using fly traps and flypaper can prevent infestations.

3. Parasites

Roundworms are the most common parasites found in pigs. They live in the gut, have a worm-like appearance (hence the name) and cause weight loss. Young pigs present the highest risk of infestation. Roundworms can block the gut and cause death. Even if the pigs survive, if the parasites are not eliminated, the pigs’ growth is permanently reduced. The parasites are eliminated with dewormers which are injected, dosed in the feed or drenched.

Tapeworm parasites live in the muscle of the pigs and cause pig measles. The pigs are seemingly not affected, but they can experience pain and have difficulties to move around. Pig meat infected with tapeworms is very dangerous for human consumption. Undercooked infected meat contains tapeworm cysts, which develop into worms in the intestines and cause serious health problems. Infected pigs can’t be treated for this parasite, but farmers should take preventive measures such as practicing good hygiene and stopping pigs from wandering around outside from the farm.

4. Salt poisoning

Salt poisoning occurs because of improper feed. Pigs fed with restaurant leftovers or with food leftovers from various sources may contain too much salt. Pigs affected by salt poisoning appear to be blind, they lose their balance and fall over, they vomit and have seizures. To prevent this problem, farmers should always ensure quality feed for their pigs.

5. African swine fever (ASF)

Outbreaks occurred over the last years makes this disease more common than it used to be. African swine fever is caused by the Asfarviridae family of viruses, which are distinct from the viruses associated with Classical swine fever. There are 22 known types of the ASF virus. The ASF infection can be introduced through several ways: contaminated feed, tick, and lice bites, contaminated medical equipment and infected pigs.

There is no treatment for the African swine fever or a live or attenuated vaccine to prevent this disease, therefore strict biosecurity measures are the only ways to prevent infection and the spreading of infections. Infected animals must be isolated and culled immediately if the presence of the virus is confirmed.

6. Foot-and-Mouth-Disease (FMD)

FMD is caused by a picornaviridae aphthovirus. There are 7 main serotypes which have in their turn many strains. More than 60 subtypes of the virus have been identified so far, therefore it’s difficult to develop an effective vaccine against it. The symptoms of FMD include lameness, excessive salivation, blisters, loss of appetite, fever, and death in severe cases.

Routine vaccination is used mainly to protect the breeding stock from FMD. However, vaccination is problematic because its protection is only short-lived. Since FMD usually occurs during winter, pigs should be vaccinated in the autumn. Furthermore, because there are several serotypes, the vaccines must be multivalent in order to be effective. The disease can be spread to and by other farm animals as well, so preventive measures should be enforced to cattle, sheep, and goats as well. There is no treatment for this disease and infected animals should be culled.

7. Rabies

Rabies is an infectious disease found in all species of homoeothermic animals, transmissible in humans, characterized by severe nerve disorders, expressed by hyperexcitability and aggression, followed by paralysis and death. To a greater or lesser extent, all warm-blooded animals are susceptible to rabies infection. In pigs, rabies usually evolves in a quick form and is manifested by strong hyperesthesia. Incubation is between 15-30 days. The pig becomes aggressive, shaky, shrieks or shouts in a hoarse voice, quickly attacks other pigs or other animals, causing serious wounds by pulling tissues. The sows devour their piglets.

To prevent rabies, farmers should be aware of the application of a complex of general sanitary-veterinary and immunoprophylaxis measures. Unfortunately, animals infected with rabies can’t be saved and the final outcome is death.

pig diseases prevention

Disease prevention in pigs

Since prevention is the most efficient way to avoid pig diseases and other health problems, it’s important to know which are the main measures to take for disease prevention in pig farms. While some disease or health problems are treatable, others can’t be treated and can become highly damaging for the entire pig stock. Some of the most important measures for diseases prevention include the following:

  • Pigs must be grown in enclosed spaces respecting hygiene conditions, the microclimate and their well-being, isolated from landfills or areas populated with other swine or wild boars;
  • Farmers must work closely with veterinarians to prevent diseases, infections and other health problems which occur in pig farms;
  • New stocks should be purchased only from sanitary-approved holdings, accompanied by official documents;
  • Feed and water must be ensured with respect to quality parameters and without administering in the feed of pigs slaughterhouse waste or non-sterilized household or restaurant waste;
  • Compliance with the welfare rules and the hygiene conditions in the means of transport for the moving swine;
  • The veterinarian should be notified immediately of any signs of disease or mortality in animals;
  • Farmers should collaborate with the veterinarian appointed for the clinical examinations and the collection of samples for laboratory examinations;
  • Fresh meat and pork products resulting from pig slaughtering in their own facilities should be consumed and/or sold only after the specialized examination provided by the veterinarian or local authorities;
  • The bodies of dead pigs infected or suspected to be infected with contagious diseases must be handled by neutralization units, with the support of local authorities.