ASCARIS SUUM PARASITISM IN FINISHER PIGS: WELFARE AND ECONOMIC IMPACTS AND CONTROL OPTIONS
S. McORIST, R. BLUNT and J. WISEMAN

Abstract
Incidence surveys indicate that intestinal parasitism due to Ascaris suum infestations are increasingly common due to the increase in organic, outdoor and straw bedding-based housing systems for finisher pigs. The relative impacts of a perceived "welfare" benefit of bedding and outdoor/organic production against parasite-induced negative health and associated pain aspects have not been fully explored. The authors assembled production and abattoir records for an integrated breeder farm complex, with 4 units, each housing approximately 1,000 sows, which supplied progeny pigs at the post-weaner phase at 8 weeks-old (25 to 30 kg bodyweight average) to several separate "grow-out" sites. The costs and benefits of interventions with either an in-feed benzimidazole (morantel) or an in-water avermectin compound were also evaluated, with appropriate controls and both A. suum-infected and non-infected grow-out sites. Negative animal welfare events, total week-by-week mortality, average daily weight gains and feed conversion data were evaluated on farms. The number of intestines infected with identifiable ascarid worms and number of livers affected with typical migrating ascarid larval lesions, known as "milk spots," were counted at specific slaughter checks. Non-infected sites remained negative during the study. On infected sites, of 1,944 untreated pigs, 846 (0.45) had detectable ascarid infections in their small intestines, of 1,920 pigs treated with ivermectin, none had detectable ascarid infection in their small intestines and of 1,980 pigs treated with morantel, 583 (0.31) had detectable ascarid infections in their small intestines. The number of livers affected with noticeable "milk spots" was 0.51, 0.46 or 0.51 in each group, respectively. The actual cost to the carcase processor of parasite-positive offal was calculated at €1 per pig. The growth rates, feed conversions and mortality rates among pigs in each group were similar. Adult Ascaris species worms are known to cause clinical signs of abdominal pain amongst animals, irrespective of other infections or factors. It was estimated that 0.26 to 0.38 of pigs exposed to A. suum in this farm system developed negative pain and welfare impacts. It was concluded that endemic A. suum parasitism had important negative impacts on animal welfare, therapy costs and abattoir incomes.

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POOR REPRODUCTIVE PERFORMANCE IN PIGS - A CASE SERIES STUDY
T.A. MARTINEZ, A. NEVEL, D.F. TWOMEY and M.R. McGOWAN

Abstract
This study was conducted in response to widespread reports from practising veterinarians in England and Wales of severe, non-specific infertility in pigs. The objective was to determine whether a distinct syndrome existed and to identify potential risk factors for further investigation.

A case series approach was taken, to recruit up to 20 herds that could demonstrate an infertility problem during October-December 2003. Practising veterinarians completed questionnaires and obtained blood samples from each farm.

After extensive advertising, 7 farms were enrolled in the study. Inadequacies of herd management software programmes limited the identification of risk factors for infertility. Returns to first service increased 4-23%, and farrowing rates decreased 6-18%, compared with the previous year. Serological evidence of porcine parvovirus, swine influenza, erysipelas and Porcine Circovirus Type 2 was detected on all farms and of leptospirosis and porcine reproductive and respiratory syndrome on some farms. No sow tested positive to the notifiable diseases Classical Swine Fever, Aujeszky's Disease or brucellosis. Potential non-infectious causes of infertility included extended semen storage times, social interactions, limited boar contact and lax biosecurity.

The case-series approach was limited by lack of participation and inadequate software packages. However, potential risk factors were identified for further investigation, and the benefit of a whole herd approach was demonstrated.

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BIOTIN - A REPORT OF AN INCREASE IN THE PREVALENCE OF A HOOF DEFECT SYNDROME IN SOWS IN IRELAND
P. SPILLANE

Abstract
The author has observed the occurrence of an increased prevalence of hoof defects in sows in Ireland in the last three to four years. The clinical signs of this syndrome are suggestive of the involvement of biotin deficiency, although declared biotin levels in feed are in line with current recommendations. The response to supplementation of the diet with additional biotin is variable. Feed ingredients, processing or storage factors could possibly have influenced the availability of biotin adversely, which could lead to an induced biotin deficiency. Alternatively, the clinical signs observed may be associated with a different aetiology. Leg weakness syndrome, genetic factors, poor conformation or housing factors could be involved, either singly or in combination.

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ATTEMPTS TO ERADICATE SOME RESPIRATORY AND ENTERIC PATHOGENS IN DANISH PIG FARMS
J. SZANCER

Abstract
For eradication of several important pathogens in Danish farms, two different procedures are primarily used at the herd level: firstly, total de-population and re-population with breeding animals from the SPF system and secondly, partial de-population combined with strategic medication. Concurrently, with the establishment of more and more farms with two-three site production, partial de-population with strategic medication has become more popular. The procedure for elimination of Mycoplasma hyopneumoniae, Actinobacillus pleuropneumoniae, Brachyspira hyodysenteriae and Lawsonia intracellularis is described below. Elimination of Sarcoptes scabiei var. suis will be mentioned. At farm level, before making the decision to go for the eradication procedure, several issues should be addressed, such as biosecurity, management and production changes, housing, and financial aspects etc. During the planning phase, laboratory, confirmation of diagnosis of pathogen/s should be carried out. After the elimination procedure has been carried out, the herd should be monitored for clinical signs and specific pathogens by using suitable laboratory tests. The de-population/re-population method is safe, with a success rate close to 100 per cent, but it is the most expensive procedure. Partial de-population and strategic medication is much less expensive, and with a consistent success rate close to 90 per cent for elimination of B. hyodysenteriae and M. hyopneumoniae. For eradication of A. pleuropneumoniae, the method is not reliable, with a success rate of less than 10 per cent after two years. Freedom from L. intracellularis infection after completing the eradication programme was, on average, two years.

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FEED RELATED INTERVENTIONS IN PIG HERDS WITH A HIGH SALMONELLA SERO-PREVALENCE - THE DANISH EXPERIENCE
J. DAHL

Abstract
The Danish salmonella programme began in 1995. Field results have not been as successful as studies under strict controls. Herds using home-mixed feed often had a lower sero-prevalence. Meal feeding increases the viscosity of the stomach contents, reduces the coliforms and increases the stomach acid. Barley may reduce sero-prevalence, organic acids will also reduce the sero-prevalence. Liquid feed will reduce sero-prevalence only if the pH is below 5.5 (I recommend 4.5). Infected weaners and growers are a potential risk. There are three main areas for control - prevent infection from entering, use hygiene to prevent spread within the herd and use feed interventions to enhance pig resistance. The practical guidelines to implement these measures are discussed.

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THE METAPHYLACTIC EFFICACY OF TULATHROMYCIN ADMINISTERED TO IN-CONTACT PIGS DURING OUTBREAKS OF RESPIRATORY DISEASE
K.S. GODINHO, R. SAMSON,R. M-L.G. WOLF, J. BULLARD, S.J. SUNDERLAND, T.G. ROWAN and V. CRACKNELL

Abstract
The metaphylactic efficacy of tulathromycin administered to in-contact pigs during natural outbreaks of porcine respiratory disease (PRD) was evaluated in six European countries (United Kingdom, Italy, Spain, Germany, Slovenia and Denmark) in a masked parallel design study with negative controls. Outbreaks were identified when approximately 25 per cent of animals in a group were exhibiting clinical signs of PRD. Once an outbreak had been established, in-contact pigs (at least 5-12 weeks old) were randomly allocated to treatment by the intra-muscular route with a single injection of either tulathromycin (n=470) 2.5 mg/kg or saline (n=471) in a 1:1 ratio at each site. There were no treatment-related adverse experiences. Across all sites, significantly greater numbers of tulathromycin-treated pigs compared with saline treated animals remained clinically unaffected with no clinical signs of PRD by both 21 days (80 vs. 70%; P=0.0002) and 42 days post treatment (78 vs. 65%; P=0.0007). By 42 days post treatment, mean percentage weight gains were significantly higher for tulathromycin treated pigs compared with saline (113 vs. 104%; P<0.0001). Metaphylactic administration of tulathromycin was found to be safe and efficacious in the reduction of clinical signs of PRD during natural outbreaks amongst growing pigs.

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COSTS OF SUB-CLINICAL ILEITIS DURING FINISHING: AN EXPERIMENTAL APPROACH
A.M. SCHOLZ, S. NUSKE, P. KREMER and M. FORSTER

Abstract
It is widely acknowledged that ileitis can cause economic losses in pig herds in the absence of any overt clinical signs such as diarrhoea or increased mortality. In order to evaluate the costs of sub-clinical ileitis, a study was performed at the Livestock Centre Oberschleissheim of the Ludwig Maximilian's University Munich comparing the biological and economic performances of pigs protected against the damage of Lawsonia intracellularis infection by vaccination against those of control animals.

The cost of sub-clinical ileitis reached 7.6 €per pig. The main factors affected were growth rate, feed conversion efficiency and carcase value. The vaccinated group had a significantly higher carcase weight (+5.7 kg/pig), a significantly higher growth rate (+56 g/d), in addition to a slightly improved feed conversion efficiency (-0.15 kg/kg). Although the carcase composition did not differ significantly between the groups, an increased payment of +0.02 €/kg was received for vaccinated animals a consequence of improved fulfillment of contract specification in AUTOFOM classification and weight category.

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PORCINE REPRODUCTIVE AND RESPIRATORY SYNDROME VIRUS: DIVERSITY OF RECENT BRITISH ISOLATES
J.-P. FROSSARD, D.G. WESTCOTT, B. NAIDU, T. W. DREW, S. WILLIAMSON and N. G.A. WOODGER

Abstract
Porcine reproductive and respiratory syndrome (PRRS) remains a significant problem for British pig producers, contributing to the porcine respiratory disease complex (PRDC), neonatal piglet mortality, infertility and occasional abortion storms. The aetiological agent, an RNA virus of the arterivirus family, has been shown to be quite diverse in other countries, but no current data regarding the virus population has been available in Britain since the early 1990s.

In the present study, genetic sequence analysis and antigenic profiling of over 100 new virus isolates (2003 to 2007) revealed that the diversity of British isolates is now far greater than during the early 1990s. Some isolates are very similar to early isolates, but a wide range of diverse viruses is now also circulating. The sequence information also indicated putative epidemiological links amongst disease outbreaks, mainly through pig movements and personnel.

Monoclonal antibody profiling also revealed increasing antigenic diversity, raising the possibility that prior exposure may not be protective. This was reinforced on several occasions by the finding of multiple strains on a farm at one time and, in one case, two different strains in one sow.

The authors' finding of increasing diversity of PRRS viruses mirrors that found in other countries and has implications for the diagnostic and prophylactic methods currently being used.

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TYLVALOSIN, A MACROLIDE ANTIBIOTIC, NHIBITS THE IN-VITRO REPLICATION OF EUROPEAN AND AMERICAN PORCINE REPRODUCTIVE AND RESPIRATORY SYNDROME VIRUS (PRRS) VIRUSES
A.D. STUART, T.D.K. BROWN and A.P.A. MOCKETT

Abstract
Porcine reproductive and respiratory syndrome virus (PRRSV) is an arterivirus that infects principally alveolar macrophages. In-vitro, the virus can be grown in selected simian cell lines, such as MA104. The macrolide antibiotics tylvalosin, tilmicosin and tylosin were tested for their ability to inhibit the replication of this virus in MA104 cells. The authors' results showed that tylvalosin and, to some extent, tilmicosin were anti-viral. Tylosin showed no anti-viral properties. PRRSV infection requires a low pH step in endosomes. We have shown that tylvalosin is able to raise endosomal pH and this may be an important mechanism by which it inhibits PRRSV replication, although other factors may also be involved.

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PREVALENCE OF FOOT LESIONS, LIMB LESIONS AND ABNORMAL LOCOMOTION IN PIGS ON COMMERCIAL FARMS IN BRITAIN AND RISKS ASSOCIATED WITH FLOORING
A.L. KILBRIDE, C.E. GILLMAN and L.E. GREEN

Abstract
A total of 103 pig farms in Britain, 21 outdoor and 82 indoor, were visited. On each farm, the feet, limbs and locomotion of pigs of all ages were examined and details of the pens in which they were housed were recorded. In general, outdoor housed pigs had the lowest prevalence of foot and limb injuries. In pigs housed indoors, there was a higher prevalence of bruising, calluses, adventitious bursae and abnormal locomotion on hard floors with little bedding, particularly slatted floors. An ideal floor to protect against physical injury in pigs is soft, non-slip and non-abrasive. Floors that currently best fit these requirements are outdoor housing or a solid floor with deep bedding.

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EFFECT OF SUPPLEMENTING FAST-GROWING, LATE-WEANED PIGLETS TWICE WITH 200 mg IRON DEXTRAN INTRA-MUSCULARLY
J. HAUGEGAARD, H. WACHMANN and P.J. KRISTENSEN

Abstract
Objective: To investigate the effect of injecting an additional 200 mg of Iron dextran to fast growing piglets at the age of 20 days, mainly fed with mothers' milk, and who already had 200 mg iron dextran injected at the age of 3 days.

Materials and Methods: 236 piglets were divided into two groups. All piglets were injected intra-muscularly in the neck with 1 ml of 20 % (200 mg) of iron dextran on day 3 post-partum. One group served as control, the other was injected with an additional 200 mg of iron dextran on day 20. The level of haemoglobin in the blood and body-weight were determined again on days 20 and 34 (the day of weaning) and weight was determined on day 50 post-partum.

Results: It was found that piglets given an additional 200 mg of iron dextran on day 20 had a significantly higher growth rate of ~20 gram per day for the first 15 days after weaning. Furthermore, those piglets had a highly significant higher content of haemoglobin at +10 g/l at the day of weaning (day 34).

Implications: On the basis of this trial, it is advised that fast growing, healthy piglets, mainly fed with mothers' milk and weaned at late age, are supplied with more than 200 mg of iron dextran.

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