Copper oxide wire particles to control H. contortus on sheep and goat farms with a range of grazing practices

Copper oxide wire particles to control H. contortus on sheep and goat farms with a range of grazing practices

Summary

Copper oxide wire particles (COWP), an alternative to chemical anthelmintics, have been shown to effectively reduced infection of barber pole worm (H. contortus) in the Southeast US. The objectives of this project are twofold.  One objective is to encourage goat and sheep farmers to limit anthelmintic use through education on innovative strategies for controlling internal parasites.  These strategies include evasive grazing, grazing forages high in condensed tannins, dosing animals with COWP, and using FAMACHA scoring and other screening techniques to selectively deworm animals. Some techniques such as COWP dosing and grazing birdsfoot trefoil (BFT) are as yet unproven in the Northeast US.  Therefore a second objective was to determine effectiveness and risks of incorporating COWP into Northeast parasite management systems and report results from Northeast COWP and BFT studies to farmers.

A study comparing the effect of dosing Boer kids with three different levels of COWP (0.5 g, 1.0 g, and 1.5 g per head) two weeks prior to weaning was conducted at one goat farm in 2015. Another study compared round worm infections in lambs receiving 3 different nutritional treatments for 8 weeks after weaning: BFT pastures, conventional pastures or hay/grain. Half the lambs on each grazing trial were dosed with 1 g COWP/head 2 weeks prior to weaning and half were not. Data have been entered into spreadsheets for further analysis. Preliminary studies of raw means indicate that, as in past years, COWP was far more effective on one sheep farm in Northern NY than in other case study farms. In depth analysis of all data is planned for 2015 to determine whether breed, diet, timing of round worm infection, and/or type of round worms influence the effectiveness of COWP. Given the current popularity of COWP, it is important to determine what factors influence its efficacy and to better educate farmers about its limitations. 

Approximately 166 people participated in three FAMACHA Certification workshops, seven “Innovations in parasite management” workshops and four on-farm parasite field days organized by our sheep and goat parasite team during 2015. Fifty three people were certified in FAMACHA. Contact information was obtained from 125 farmers to track whether their methods of managing internal parasites changed after participating in these activities. A follow up survey was developed and heavily edited with plans to distribute to past attendees in Feb 2016.

Objectives/Performance Targets

Of 100 participating farmers surveyed, 75% will report deworming less and reducing their chemical dewormer costs by as much as $215 in a 100-doe or ewe flock, citing adoption of FAMACHA and other non-chemical internal parasite control methods. The low dose of COWP will reduce deworming cost by $142 compared with chemical dewormers with the added potential benefits of some farmers being able to meet organic farming standards and other farmers maintaining the effectiveness of selective use of chemical anthelmintics. Most importantly, these strategies both reduce deaths from internal parasites from as many as 18 animals per year to 5 animals per year, increasing income by $2,205 in a herd or flock of 100 mature females.

Accomplishments/Milestones

1. Three-thousand sheep and goat farmers learn about this research and extension project and are directed to an on-line survey about their methods of controlling H. contortus and other internal parasites. In May 2014 we invited our database of >3000 sheep and goat farmers to participate in the preliminary survey. Valid emails limited the list to approximately 2000 addresses and further mis-identification of our bulk email invitation as spam resulted in about 1200 addresses receiving the survey announcement.
2. Five-hundred farmers complete the survey and 300 agree to receive additional information about controlling H. contortus with minimal use of chemical anthelmintics. Of 194 respondents within one month of the invitation, 168 respondents fully completed the survey. However, as can be seen in the following milestone, attendance at our workshops providing information on controlling H. contortus with minimal use of chemical anthelmintics has easily exceeded 700 people by 2016.
3. Two-hundred farmers attend field days, workshops at regional conferences, or extension programs to learn directly about control of H. contortus and other internal parasites using COWP and other methods, such as FAMACHA scoring, evasive pasture management, and forages high in condensed tannins. Twelve farmers agree to do the research with COWP. As of December 2015, 744 people have attended our integrated parasite management workshops, field days and FAMACHA certification programs describing COWP and other innovative parasite control methods with potential to help control worms, 335 people have been certified in FAMACHA and approximately 422 farmers have provided follow up contact info to track how their parasite management changes. However, we still need to complete screening the contact info to eliminate duplicates or members of the same farm.
4. Seven farmers carry out the research with COWP. One-hundred participating farmers respond to follow up questionnaires or interviews on changes made in internal parasite management. In 2013, four NY sheep or goat farms participated in our COWP studies using funding from other research sources. In 2014, three sheep farms (one repeat) and one meat goat farm in NY participated in our 5 on-farm COWP studies conducted with funding from NESARE and other research sources. In 2015, two farms (one repeat) conducted COWP studies. We are also conducting studies on the effect of grazing Birdsfoot Trefoil on parasitic worm infections in sheep and goats. Eleven Northeast farms have established their BFT field. Six conducted grazing trials in 2015 and 5 plan to start grazing trials in July 2016. Follow up questionnaires to our 2013, 2014 and 2015 workshop participants asking them about parasite management changes they have implemented will go out to approximately 422 farmers in Feb/Mar 2016.

Impacts and Contributions/Outcomes

In 2014, COWP dosing to control barber pole worm did not appear very effective in flocks and herds where kids and lambs were “self-weaned” and supplemented with concentrates as compared to flocks where lambs received little concentrate and were dosed with COWP 2 weeks prior to weaning. The 2015 COWP studies focused on  the effect of COWP dosing 2 weeks pre-weaning on 1) Boer goat kids weaned at ~10 weeks of age and provided with some concentrate pre and post weaning, and 2) Dorset X lambs under three different nutritional regimens: conventional pastures (CP), BFT pastures (BFT), or hay/grain (HG).

Kid study

Eight kids each were assigned to the following treatments: Control (no COWP), 0.5 g/head COWP, 1.0 g/head COWP, and 1.5 g COWP/head.  Dosing with COWP occurred 2 weeks pre-weaning.  Fecal samples and FAMACHA scores were taken every 2 weeks from 2 weeks pre-weaning until 4 weeks post weaning. Average increase in barber pole worm egg counts was highest for the Control treatment (+4262 epg), lowest for the 1.5 g COWP treatment (+2373) and intermediate for 0.5 g COWP (+3215 epg) and 1.0 g COWP (+3048 epg) over the 6 week study (Figure 1) but must await further analyses to test if the differences were significant. Future studies in goat kids, but not lambs, might include dosages of 2.0 g COWP per head to determine if this higher dosage results in further improvements in barber pole worm control.

Lamb study

Eight lambs each were assigned to the following treatments: BFT + COWP, BFT alone, CP + COWP, CP alone, or HG + COWP. Fecal samples and FAMACHA scores were taken every two weeks from 2 weeks pre-weaning until 8 weeks post weaning.  Lambs were weighed 2 weeks pre-weaning, at weaning and 8 weeks post weaning. All lambs that received COWP 2 weeks pre-weaning appeared to have lower round worm egg counts and more desirable FAMACHA scores for eight weeks post weaning as compared to the group of lambs that were grazed on BFT alone and especially the group of lambs that were grazed on CP alone. These changes in roundworm egg counts resulted almost entirely from changes in the barber pole worm egg population. We were excited by the dip in worm egg counts for the two BFT groups at 6weeks post-weaning although it appears to have been temporary (Figure 2).  In addition, no lambs on the BFT pasture alone, the BFT + COWP or the CP + COWP treatments had to be dewormed over the 70-day experiment.  In contrast, 2 lambs required deworming on the HG + COWP treatment, and 4 of 8 lambs grazed on the CP alone had to be dewormed based on severe anemia and weakness. Daily weight gains over the 70 d study averaged 0.3 lb, 0.25 lb, 0.22 lb, 0.18 lb, and 0.16 lb for BFT + COWP, HG + COWP, BFT, CP + COWP and CP treatments, respectively.

Further analyses of our COWP and BFT studies will 1) provide better clues as to why the efficacy of COWP varies among farms and 2) help determine whether the use of BFT pastures during post-weaning stress is justified despite difficulties in establishing heavy stands of BFT and its relatively slow regrowth compared to conventional clover/grass pastures.  

Interest in study results is strong as evidenced by high attendance at field days and workshops and invitations to speak at winter conferences.  We are seeing several repeat participants at our outreach activities and these repeaters seem especially aware of limitations in BFT and COWP use and the importance of selective deworming and evasive grazing techniques.

• Figure 1. Effect of level of COWP on fecal egg counts.
• Figure 2. Effect of grazing birdsfoot trefoil (BFT) and/or administration of copper oxide wire particles on fecal egg counts.

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