Progress report for LS22-363
Grazing with the Fun Guy (or fungi). This project will show it is possible to provide a strategy to offer the fungus (see photo of parasite larvae trapped by Duddingtonia flagrans fungus), which controls gastrointestinal worms on pasture leading to improved animal health and productivity, and enhancing sustainability of livestock farms.
Since our first SARE R&E grant in 2002 (LS02-143), we have strived to include nematode-trapping fungus (Duddingtonia flagrans or Df) in the toolbox for livestock producers to control gastrointestinal nematode (GIN) parasites. However, commercialization of the fungus (BioWorma®) took 17 years! GIN are the major health threat for ruminant livestock confounded by dewormer resistance, leading to anemia, poor weight gains and death. The goal of sustainable farms is to eliminate chemical inputs and control GIN; the fungus brings this closer to reality. The fungus can remove much of the GIN on farm. Approximately 90% of GIN are found on the pasture and 10% in the animal; Df can reduce up to 90% of larvae on pasture. The product is considered costly by most farmers (between $0.20 to 0.60 per 100-pound animal per day). Thus, it is imperative to build a strategic program for farmers that considers effectiveness and economics. For example, can Df be fed every other day, or every other week or only in loose mineral supplements? These questions will be answered in research flocks/herds and on farm by examining changes in fecal egg counts, pasture larval counts and/or animal worm counts.
The fungus as part of the farm system will be considered among other management tools to minimize worms and optimize animal health. These include genetic resistance to lower GIN infection and increase economic value (current grant, OS19-124), and use of copper oxide wire particles (COWP) as a dewormer (included in CVs of PIs). These can lead to reduced time spent on GIN management, increased animal growth and production since the immune system is not overburdened, and a greater regenerative agriculture potential without the reliance on chemicals.
We have a rich outreach program through the American Consortium for Small Ruminant Parasite Control (www.wormx.info) which meets twice yearly including virtual meetings. Dr. Whitley is a small ruminant specialist with a strong extension program providing several farmer training sessions yearly (virtual or live) and on an ACSRPC extension committee to produce videos, fact sheets and translation of farmer publications to Spanish. We will communicate with K. Matthews, Delaware State University (LNE21-418), an ACSRPC member also investigating the use of Df. Thus, we can disseminate findings and build recommendations for use of the fungus in the farm system. We will work with Susan Schoenian, University of Maryland (expected to retire) ACSRPC website developer, on progressive development of the ACSRPC website to gauge the frequency of use of materials on the site. We will explore ACSRPC on Facebook and develop more infographics and sound bites of information to lead to more in depth info on the website.
- Examine practical approaches to administer Duddingtonia flagrans (Df) to sheep and goats to obtain good gastrointestinal nematode (GIN) control.
- Examine complementary approaches of using genetics, Df and other GIN control technology within the small ruminant grazing system.
- Develop new outreach materials as fact sheets, videos and webinars in collaboration with farmers, and increase use of available technology for GIN control to disseminate strategies of GIN control that minimize the need for deworming.
Validation trial. Lambs will have access to grass pastures contaminated with parasitic nematode larvae before trial begins and will be naturally infected. In early January 2023, Katahdin lambs, ~90 days of age, were randomly assigned to 2 treatments (8/treatment; 2 lambs/pen for feeding): 1) control (no D. flagrans or BioWorma), 2) D. flagrans or BioWorma (International Animal Health Prod. Pty. Ltd., Huntingwood, NSW, Aust; Lot no. 3167101, mfr Oct, 2022). All lambs received the same grain supplement and trace mineral mixed into feed fed per kg body weight (Premier Sheep Trace Mineral Premix mixed with salt at a rate of 5:50 per manufacturer recommendations). Lambs were acclimated to pen feeding for 7 days before beginning treatment diets for 7 days. Lambs weighed ~25 kg and were fed 60 mg BioWorma/kg body weight daily. Lambs were housed together and brought into pens in pairs for feeding daily then returned to plots after feeding, and had free choice bermudagrass plus alfalfa hay, water, and access to shelter/shade.
Sample Collection: Feces were collected on first day of diet acclimation, then, one week later there were three sample day collections every other day to determine fecal egg count (FEC). Feces were cultured to examine L3 recovery rate (L3 larvae/FEC) relative to control group and determine the predominant gastrointestinal parasite (H. contortus or Trichostrongylus spp.; plus Cooperia spp. or Oesophagostomum spp.).
Full study. Katahdin lambs, 3 months of age, had access to grass pastures contaminated with parasitic nematode larvae before trial began and were naturally infected. Lambs were randomly assigned to treatments (8/treatment; 2 lambs/pen for feeding): 1) control (no D. flagrans; CON), 2) D. flagrans as BioWorma (BioWorma dose based on the heaviest animal within the group) as recommended top dressed on grain supplement (DfCON), or 3) D. flagrans as BioWorma (same dose as Trt 2) mixed in 7 g/head of a trace mineral mix (Premier Sheep Trace Mineral Premix mixed with salt at a rate of 5:50 per manufacturer recommendations; DfMIN). The mixed mineral and salt were mixed with BioWorma and stored for 7 days before top dressed onto lamb’s supplement. All lambs received the same supplement and trace mineral mix fed per kg body weight. Lambs were acclimated to pen feeding and diets (control) for 7 days before beginning treatment diets for 21 days. Lambs weighed ~25 kg and were fed 60 mg BioWorma/kg body weight daily for 28 days. Lambs had free choice bermudagrass plus alfalfa hay, water, and access to shelter/shade.
Sample Collection: Starting on first day of diet acclimation, blood and feces were collected every 3 days (on Mon or Tuesday, and Thur) for determination of blood packed cell volume (PCV; every 7 d) and FEC. Feces will be cultured throughout the trial to examine L3 recovery rate (L3 larvae/FEC) relative to control group and determine the predominant gastrointestinal parasite (H. contortus or Trichostrongylus spp.; plus Cooperia spp. or Oesophagostomum spp.; still need to be identified). Lambs were weighed at start/end of trial.
Duddingtonia flagrans included in trace mineral mix or feed for control of gastrointestinal nematodes in sheep
J.M. Burke, K. Petersson, E. Kass, J.E. Miller, A. Vatta, M. Acharya, S. Rohila
Objective was to determine efficacy of Duddingtonia flagrans (Df) included in a mineral mix compared with a feed supplement in Katahdin ewe lambs weaned Jan 2022 (76 ± 2.0 d of age; 21.2 ± 1.1 kg). Lambs were supplemented in pairs with a 12% CP sweet feed (226 g and 6 d later 450 g/lamb) that was thoroughly mixed daily with trace mineral mix [7.1 g salt (87.7%), Sheep Trace Mineral Premix (8.8%), and Vitamin ADE mix (3.5%), Premier 1] and coccidiostat (0.2 g of Decoquinate Type A as Deccox®, Premier 1). Lambs were randomly assigned to one of three treatments (n = 8/treatment; 2/pen): 1) control (CON) of no Df, 2) Df (BioWorma® Int. Anim. Health Prod.) mixed in supplement as recommended (DfC; weighed daily at 1.7 g/lamb), or 3) Df added in mineral (DfM; trace mineral was mixed with 13.6 g Df for 8 lambs then stored for 7 d in a Ziploc bag) which was then added to the supplement. The Df dose used was for the heaviest lamb. Pair feeding lasted 1 h, then lambs had access to free choice bermudagrass hay and water. Fecal samples were collected for fecal egg counts (FEC) and coproculture in pairs twice weekly, and blood collected to determine packed cell volume (PCV) weekly between d -2 and 27. Larval recovery was calculated per pair: (L3/g feces/average FEC) × 100. GIN were 51.3% Trichostrongylus spp., 44.9% Haemonchus contortus and < 2% each of Cooperia spp., Oesophagostomum spp. and Teladorsagia spp. Most samples contained some Strongyloides. FEC were log transformed; FEC, PCV, larval recovery were analyzed using repeated measures over time. There was a treatment × date interaction for FEC (P = 0.02) but DfM was similar to CON throughout. PCV were similar among treatment groups (P > 0.10). Surprisingly, larval recovery was similar among treatments (P > 0.10). In working with the Df manufacturer, it was determined that spore count of the BioWorma of this lot number was ~10-fold lower than anticipated (possibly due to mixing) or required for expected larval recovery. In addition, the coccidiostat mixed in the feed may have had an adverse effect on Df viability and deserves further attention. A subsequent study was conducted using BioWorma from a new lot, validating the spore viability and repeating the objective. Results will be presented in next report. Implications are that Df products should be tested for viability before use. This has prompted us to develop simple in vitro cultures to be conducted before research studies. These in vitro studies will be presented in the next report.
Educational & Outreach Activities
The website of the American Consortium of Small Ruminant Parasite Control has been updated to include several Spanish translations of fact sheets and infographics: ACSRPC | En español (wormx.info). In addition there were 10 fact sheets published on Other Worms: ACSRPC | Other Worms (wormx.info), and 11 infographics (ACSRPC | Infographics (wormx.info)). An article was written for the Eastern Alliance Katahdins on how selection for parasite resistance in sheep affects other important traits: How Does Selection for Parasite Resistance in Katahdin Sheep Affect Other Important Traits? - Eastern Alliance for Production Katahdins (easternalliancekatahdins.com). The ACSRPC will hold their annual meeting at Louisiana State University in May 2023 to present research reports.
A field day at Dale Bumpers Small Farms Research Center, Booneville, AR occurred on April 29, presenting an update to use of nematode-trapping fungus to control parasites on pasture, and other alternative measures of parasite control. A webinar on worm control in small ruminants was presented at a train-the-trainer event at Lincoln University and at a producer's conference in Texarkana in April 2023. A train-the-trainer event was held at Tuskegee University and PIs presented information on small ruminant parasite control.
Farmers gained knowledge in use of copper oxide wire particles as an alternative to resistant dewormers to control parasites, and proper use of feeding fungus for pasture control of worms.
We are still early in our project. There were issues with the Duddingtonia flagrans (fungus) product used and the initial research study had to be repeated three times, including by a colleague at University of Rhode Island. Once a new lot of the fungus became available, we determined that the fungal spores were viable and the product worked as expected in reducing larval recovery when animals were fed according to manufacturer's directions, and the spores included in a loose mineral worked even better than that treatment. Thus, field studies can now be conducted at LSU and FVSU. In addition, a producer collaborator working on the genetics objective failed to meet the requirements outlined, and in fact, the high parasite resistant rams were returned to ARS in very poor condition (and have since recovered). Another producer cooperator had a dog attack her flock and may not have adequate number of lambs per sire. Thus, we are searching for another farmer collaborator and allowing the second cooperator an additional year of breeding and evaluation. This section will be revised in 2024.