A couple of studies reported in the scientific literature have failed to show a benefit to feeding nematode-trapping fungus (Duddingtonia flagrans). Studies involved dairy sheep in Switzerland, commercial sheep in Sweden, and lambs and kids in Germany.
Dairy ewes in Switzerland
A field study was conducted on three sheep farms in Switzerland to investigate the efficacy of Duddingtonia flagrans against naturally-acquired infections of gastrointestinal nematodes in adult dairy sheep. On each farm, the ewes were divided into two equal groups. One group received the spores for four months; one group served as a control.
At an overall moderate infection level, in all farms D. flagrans did not have a significant effect on the observed parasitological parameters with the exception of a significantly reduced herbage infectivity in one farm. In contrast, the results from fecal cultures indicated a mean suppression of larval development during the fungus-feeding period between 82, 89 and 93% on the three farms, respectively.
Source: Veterinary Parasitology, June 2007
Commercial farms in Sweden
Trials were conducted on three commercial farms in Sweden to assess the effect of administering nematode-trapping fungus Duddingtonia flagrans, together with supplemental feeding to lactating ewes, for the first six weeks after turnout on pastures in spring. Control groups, which received only feed supplement were established on all three farms.
No difference in lamb performance was found between the two treatments on all three farms. This was attributed to the high levels of nutrition initially of the ewes limiting their post-partum rise in nematode fecal egg counts in spring. Additionally, pastures were of good quality for the lambs during the finishing period, and all lambs were treated twice with an anthelmintic.
Source: Acta Vet Scand. 2006
Kids and Lambs in Germany
Twenty female goat kids and twenty female lambs were used in a study in Germany to determine the efficacy of Duddingtonia flagrans. Kids and lambs were kept on pasture and fed an additional concentrate diet. There were divided into two groups, with half being fed the spores and half serving as controls.
After 90 days of spore feeding, the control goats had an arithmetic mean FEC of 1230 (±533) epg, compared to 517 (±671) epg in the fungus-fed group. There were no statistical differences in the lamb groups. At the end of the study, the mean body weight gain in the fungus-treated groups tended to be higher than in the control groups, but differences were not statistically significant.
Veterinary Parasitology, January 2009