Beyond the everyday production costs of the livestock farmer, feed,overhead, veterinarian, transport, PARASITIC SUPPRESSION of animal performance can be devastating economically. Moreover, nematode worm infestation is historically a troublesome burden on optimal production for graziers. For cattle and small ruminants, effective chemical anthelmintics have been a reliable crutch for standard non-sustainable farmers to count on, but this therapy has been losing its effectiveness with increasing worm resistance.Organic graziers have had to emphasize critical management stategies like rotational grazing and genetic selection, because a parade of ineffective ‘wormers’ or agents with distorted or anecdotal efficacy continue to cloud the literature.However, the Organic community must continue to seek non-chemotherapeutic anthelmintics, BECAUSE their existence would be highly useful to the organic grazier during emergency situations(no loss of the animal’s organic certification) or integrated into a planned parasite control strategy.
We performed a scientific on-farm study to try to establish the anthelmintic efficacy of the natural chemical Plumbagin by using Plumbago zeylanica plant extract.Plumbagin has been shown to have anti-parasitic properties invitro , and we sought to establish its effectiveness and safety invivo both as a preventative and therapeutic agent in sheep. Haemonchus contortus ,who has a devastating impact on grass-fed sheep production,was chosen as the studied nematode target.
Three trial groups(control,preventative, therapeutic) containing 10 feeder lambs each were studied using the Fecal Egg Count(FEC),Packed Cell(PCV), and Total Solid(TS) indices to measure Plumbagin’s efficacy after a challenge of 5000 infective H.contortus L3 larvae. Unfortunately, we demonstrated that Plumbagin was ineffectual as a preventative and therapeutic organic anthelmintic.
After initial positive data showing lower fecal egg counts and higher PCV’s in the Therapeutic group, results were found to be statistically insignificant.
Our objectives in this study were 2-fold.First, was to establish Plumbagin as an organic anthelmintic in the Preventative role.
Secondly, to demonstrate Plumbagin’s efficacy as a Therapeutic anthelmintic, that is, as a treatment against patent adult H.contortus infestations.We performed the triple chemical worming initialy on the study animals to chemically “cleanse” all of the patent nematode infestations the lambs may have been carrying.This has been shown to be effective because it is extremely unlikely that nematodes would be resistent to 3 separate anthlmintic categories,each killing in a different way:Albendazole is a benzamidazole,Levamisole is a imidazothiazole, and moxidectin is a semi-synthetic derivative of nemadectin.
A minimum 2 week “rest” period was necessary because moxidectin is an effective larvicidal for up to 2 weeks post administrion. In the Preventative role, we would expect the Plumbagin-treated Preventative group to have statistically significant lower fecal egg counts(FEC) than the Control group at the 1 month(Day0) follow-up FEC.
The P.zeylanica extract was dosed 2 days prior to L3 dosing to make sure Plumbagin was “on-board” to kill the infective L3 larvae when they were dosed……..mimicking a highly infected pasture.We would not expect a significant difference in PCV’s at 1 month because the patent infection of H.contortus adults would be so short(19-21 day pre-patent period).To refresh, H.contorus adults are so deadly because they suck blood in the sheep’s abomasum causing anemia ie.lower PCV’s and lower TS’s In the Therapeutic role, we would expect the Pumbagin-treated Treatment group to have statistically significant lower FEC’s and higher PCV’s/TS’s than the Control group at day 7,14,and 21 days post p.zeylanica root extract dosing at day0-day4.
We performed a day21 FEC to rule out a possible egg suppressive effect of Plumbagin vs a killing effect of H.contortus adults. We would expect to see an egg “Rebound” at day 21 if Plumbagin only suppressed H.contortus adult egg output.