Non-midical control of parasitic worms in pigs

Generally there is a higher prevalence of intestinal parasites in organic pigs compared to conventional indoor pigs. It may be possible to reduce infection levels by ensuring that new animals are parasite free, using a moderate stocking rate, co-grazing cows and sows, using noserings, altering feed composition and feeding the pigs predatious fungi. In addition, paddock rotation is recommended in order to remove the pigs from the infectious parasite stages (eggs and larvae). Resent results show that the free-living larvae of the nodular worm do not survive for long on pasture. Overall, the nodular worm is considered to be less of a problem than other parsites. Eggs from the large round worm and especially the whipworm can take long to become infective but may in return survive several years in the soil. It seems as if ploughing may reduce the transmission of whipworm considerably, whereas the effect on the large round worm is not as strong. The large differences between the three parasites mean that control strategies may have to be designed according to the parasites present in a given herd

Oesophagostomum dentatum and Trichuris suis infections in pigs born and raised on contaminated paddocks

SUMMARY Transmission of Oesophagostomum dentatum and Trichuris suis was studied in outdoor reared pigs. Six farrowing paddocks were naturally contaminated in May to mid June 2001 by experimentally infected seeder pigs. Early July, 1 sow farrowed on each paddock and starting week 3 post partum (p.p.) the offspring was slaughtered serially every 2 weeks for recovery of O. dentatum and T. suis. Faeces was collected regularly for parasite egg counts and acid-insoluble ash (AIA) content as an indicator for geophagy. Weaning took place week 7 p.p. by removing the sow. Paddock infection levels were estimated in mid June (O. dentatum) and late November (O. dentatum and T. suis) using helminth naïve tracer pigs. Soil and vegetation samples were collected regularly. Despite a high initial contamination by the seeder pigs, O. dentatum paddock infectivity was negligible to low throughout the raising of the experimental piglets, which had a slow accumulation of nodular worms ending with a mean of 422 worms/pig week 19 p.p. As only few eggs developed to infectivity overall T. suis transmission was minimal. The first T. suis were recovered week 11 p.p. and the highest mean burden of 21 worms/pig was recorded week 19 p.p. The experimental pigs had high faecal levels of AIA though it was decreased from 53 % in 3 weeks old piglets to 15 % in 19 weeks old pigs. The results are discussed in relation to the biological characteristics of the 2 parasites and their occurrence in organic pig production

Long-term survival of Ascaris suum and Trichuris suis eggs in relation to pasture management

Background: Organic pig production systems are commonly characterized by high helminth prevalences. This problem is partly associated with access to outdoor facilities such as pastures and more knowledge is needed on long-term pasture infectivity patterns to improve farmer advisory services and guidelines on pasture management. Methods: Six identical paddocks were originally contaminated in the spring to autumn of 2001 by pigs infected with high levels of Ascaris suum and low levels of Trichuris suis. Since then, no further eggs have been deposited and 3 of the paddocks have been ploughed to a depth of 20 to 28 cm and re-sown once a year while 3 paddocks remained untouched apart from yearly cutting of the vegetation. In the late spring and late autumn of 2001, 2002, 2003, and 2004 as well as in the autumn of 2005, 2007, and 2010, survival of parasite eggs was measured by analysis of soil samples and by recovery of worms from short-term exposed helminth naïve tracer pigs. Results: Following a high initial egg mortality in 2001-2002, the number of parasite eggs in the soil declined slowly over time for both species. In 2001, very few T. suis eggs developed to infectivity. The tracer data show that overall pasture infectivity for T. suis did not peak until 3-4 years after the initial contamination. Preliminary data from 2010 indicate that T. suis is still present on the paddocks, though at very low levels. Infective A. suum eggs were detected in 2001 and paddock infectivity levels peaked within 2 years after contamination, resulting in livers with very high numbers of white spots, irrespective of paddock treatment. Transmission of T. suis was more consistently reduced by ploughing compared to A. suum. Conclusion: Development and maturation of A. suum eggs and especially T. suis eggs was overall slower than expected, indicating that pasture rotation schemes should ideally exceed 3 years. However, 9 years after initial contamination, both species were still detected and A. suum pasture infectivity was still too high for the paddocks to be suitable for pigs. Overall, transferring the eggs deeper into the soil by ploughing appeared to reduce parasite transmission

Ascaris suum infections in pigs born and raised on contaminated paddocks

The transmission of Ascaris suum was studied in outdoor reared pigs. From May to June, 2001 6 farrowing paddocks were naturally contaminated with A. suum using experimentally infected seeder pigs. Early July, 1 sow farrowed on each paddock. One piglet per litter was slaughtered every second week starting week 3 post partum (p.p.) for registration of liver white spots and recovery of A. suum from the lungs and the small intestine. The last pigs were slaughtered week 19 p.p. Faeces was examined for eggs and blood was analysed for A. suum specific antibodies. Weaning took place week 7 p.p. by removing the sow. Paddock infection levels were estimated by regular examination of soil samples and in late June and late November using parasite naïve tracer pigs. Paddock contamination was high but eggs developed slowly resulting in a low initial transmission to the experimental pigs. By week 5 p.p. transmission had increased and the numbers of infective eggs in the soil increased during the study. The results indicate a continuous uptake of infective eggs, but visceral larval migration was reduced with time probably due to the development of a pre-hepatic barrier. Nevertheless, a rather large population of adult worms remained in the pigs throughout the study, and it may primarily have been eggs ingested in the early infection phase that gave rise to the patent infections. It is suggested that neonatal exposure may result in increased persistence and size of adult worm burden and that the higher ‘life time worm burden’ may be of significant economic importance

Spolorm i økologiske svinebesætninger

Spolormen er en parasit, der lever i tarmkanalen og er udbredt i alle egne af verden, hvor der holdes grise. Spolormen kan være et problem, fordi den kan påvirke grisens tilvækst, foderforbrug og sundhed. Et igangværende treårigt Organic RDD projekt (PAROL) arbejder derfor på at kortlægge smitten i fem danske besætninger, for at forbedre rådgivningen omkring kontrollen af spolorm

Survival and development of Ascaris suum and Trichuris suis eggs in deep-litter on an organic pig farm

Background: Helminths are common in European organic pig production systems and the use of deep-litter has long been considered a serious risk factor contributing to this problem. However, until now hardly any data has existed to either support or reject this hypothesis, thus complicating formulation of farmer guidelines. Methods: On an organic Danish pig farm, 3 different areas (latrine, resting area and the area in-between) of 2 indoor fattening pens with deep-litter (min. 2 months old) were examined for Ascaris suum and Trichuris suis eggs. The deep-litter was sampled vertically 10, 20, 30, 40, 50, and 60 cm from the surface, by pooling 4 sub-samples per level. In addition, eggs were isolated from the top, middle, and bottom of deep-litter (3-4 months old) of the same areas but in 3 other pens. Percentage embryonation was determined before and after incubation in H2SO4 at 25OC for 7 weeks. For comparison, control eggs isolated from fresh faeces were also incubated. Results: Though less common in the resting areas, eggs of A. suum (0-481 eggs/g dry litter) and T. suis (0-58 eggs/g dry litter) were detected in all pen areas and vertically throughout the deep-litter, but the large majority of eggs was unembryonated and some were damaged. Hardly any eggs were partially or fully embryonated. Once isolated and given optimal conditions, eggs of both species from all 3 areas were able to develop to a larvated stage, but the ability to do so declined with the depth within the deep-litter. Compared to control eggs from faeces, A. suum eggs from deep-litter were less successful in embryonation while T. suis eggs from deep-litter had the same percentage embryonation as fresh eggs. Conclusion: For the first time data has shown that deep-litter may not be a risk factor for A. suum and T. suis transmission within the pens as previously suspected. However, it does appear that a high number of eggs may survive and potentially embryonate if they are transferred to a more beneficial environment. The consequence being that manure should not be spread indiscriminately onto pastures, which may later be used for pigs. A solution may be to inactivate the eggs first

Ikke-medicinsk kontrol af indvoldsorm i grise

Der er generelt en højere forekomst af indvoldsorm i økologiske grise i forhold til indendørs grise. For at reducere forekomsten af indvoldsorm kan man bl. a. sørge for at nye dyr er parasitfri, holde en moderat belægningsgrad, samgræsse søer med kvier, bruge næsering, ændre foderets sammensætning og fodre grisene med rovsvamp. Derudover anbefales det at man benytter foldskifte, så man fjerner grisene fra smittekilden (ormenes fritlevende larver og æg). Et større markforsøg har vist at larver af knudeormen overlever dårligt i det fri og må overordnet anses for at være et mindre problem. Æg af spolormen og piskeormen kan derimod overleve i flere år selvom især pisleormens æg kan være lang tid om at blive infektive for grise. Grises optag af æg af piskeormen ser ud til at kunne reduceres ved at pløje markerne, mens effekten ser ud til at være mindre for spolormen. De meget store forskelle imellem de tre ovennævnte indvoldsorm gør, at kontrolstrategier bør tilpasses afhængig af hvilke orm, der findes i en given besætning