Efficacy of a Novel Herbal Dewormer on Katahdin Lambs

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Introduction:

Most shepherds are familiar with the need to deworm their sheep and the added stresses that go along with it. Over time, the Barber Pole Worm and other economically devastating parasites have become more resistant to conventional dewormers, creating a quickly growing need for alternative deworming practices. An effective herbal dewormer could be a solution available to sheep farmers, especially those using organic practices. During the summer of 2022, for our senior capstone study at the University of Maine, we tested the novel herbal dewormer Early Bird to evaluate whether it was an effective option.

Early Bird is a commercially available dewormer marketed for use in sheep, goats and camelids; especially those that have had chronic issues with dewormer resistance. Early Bird is administered in two “phases” of different herbal mixtures that are added to a supplemental feed over the course of a week for each phase. The first phase contains herbs to kill multiple species of gastrointestinal nematodes (GIN), thus deworming the animal. The second phase is designed as an immune-boosting blend of different herbs that helps prevent worms from re-establishing and helps compromised animals bounce back from infection[1]. Our hope was to see a reduction in fecal egg counts (FEC) for our treatment groups without any adverse effects from using the product. 

Methods:

 To test Early Bird’s effectiveness for treating GIN, we set up a feeding trial with 46 Katahdin lambs aged 5-6 months at Waldoview Farm in Winterport, Maine. Individual lambs were randomly assigned to a control or treatment group with an even spread of ewes and rams. During the study, lambs grazed timothy/orchardgrass pasture and had received no additional supplementation since approximately 10 to 12 weeks of age. All lambs were intentionally exposed to parasite larvae at the same time on a commingled pasture one month prior to our study. An initial pooled fecal sample determined that the lambs were facing a parasite challenge (>500epg) at the start of the study.

The herbal mixture was fed over a molasses sweet feed. To ensure the treatment lambs were getting the proper dosage, we individually fed each lamb once a day for two weeks, following the manufacturer’s instructions. The herbal topdressing was lightly mixed into the grain to assume even consumption of the treatment. Phase 1 was top dressed at 1⁄2 tsp/day for the first three days and then the dosage increased to 1 tsp/day for the next four days to conclude the first week of treatment. Immediately following the Phase 1 treatment, the Phase 2 blend was top dressed with 1 tsp/day for 7 days. The control group was fed the same grain as the treatment group sans the herbal mixture. We offered every lamb the same amount of grain each day for the duration of the trial. Refusals were weighed and recorded. Lambs eating less than 80% of the treatment (grain+herbal dewormer) were excluded from analyses.

To measure Early Birds efficacy, we collected fecal egg count (FEC), weight, body condition score (BCS), FAMACHA© score, and packed cell volume (PCV). These were taken at the beginning of every week starting at week 0 (before any treatment) and ending at week 3 (a week after the second phase of treatment was completed).

Results:

Statistical analysis of the data collected showed that there was no significant change in fecal egg counts between the control and treatment groups over the four weeks (P=0.371). Among ram lambs, we observed slight variation in FEC over the course of the study with control rams having a nominally higher count at each collection. However, among ewe lambs, FEC for treatment and control groups were essentially identical throughout the project. The treatment group experienced a significant 10% drop in PCV from week 0 to week 3 (P=0.002), indicating potential anemia. The control group showed only a 0.5% change in PCV. We saw no trends or major changes in body condition, weight and FAMACHA© score over the course of the study.

Discussion:

 Our lack of significant change in fecal egg count could have been for a number of different reasons. The changes in egg load for both groups could have been caused by seasonal self-correction, differences in nutritional planes or other environmental factors. So, our results do not necessarily mean the product didn’t work, just that in these Katahdin lambs it did not appear to be an effective alternative to conventional dewormers.

Upon reviewing the different ingredients that make up Early Bird, we found evidence that these herbs indeed have the potential as a dewormer and to aid with internal recovery. The overall look and smell of the treatment was not dissimilar to an herbal tea. One of the herbs in the first phase of Early Bird is Wudani Leaf, which was chosen to directly combat the eggs before they are excreted and hatch. As it was found to damage the outer layer of parasite eggs in a separate study[2]. This has potential to reduce pasture contamination by worm eggs and consequently reduce exposure in other lambs. The second phase focused more on recovering from the effects of a parasite load and included herbs like Mongolian milkvetch and a perennial shrub root, Atractylodes Macrocephala. Mongolian milkvetch, for example, was found to be beneficial to the animals by increasing their immune response[3]. Similarly, another herb that was used, a perennial shrub root Atractylodes Macrocephala, has been found to increase intestinal epithelial cell migration. This effect could help the animal recover from any internal damage done by parasites[4].

As seen in Figure 1, we noticed a slight, though not statistically significant, decline in fecal egg counts for the ram lambs, especially those in the control group. We believe these lambs were undergoing a natural self-correction. Some lambs may have been experiencing a parasite challenge for long enough that their bodies began building their own immune response just before or as we began our study. Another factor we believe may have affected FEC is the nutritional differences between pastures for the lambs. As shown in Figure 1, the ewe lambs were facing much less of a challenge with an average FEC at just over 500 epg while the ram lambs were facing nearly three times that. We attribute this not to differences in exposure, but rather to the ewe lambs grazing what we felt was better quality pasture. That higher plane of nutrition likely helped their immune systems to fight the effects of parasitism better than in the ram lambs.

Figure 1. Average eggs per gram (epg) of each treatment and control group from four collection periods at week long intervals. Week 0 is the baseline collection before any treatment. Week 1 collection occurred after feeding Phase 1 treatment. Week 2 collection occurred after feeding phase 2 treatment. Week 3 collection occurred a week after the end of Phase 2 treatment. Includes data only from individuals who ate 80% or more of the treatment.       

The 10% decrease in PCV of the treatment group was not an expected result. We would expect to see a decrease in PCV from the control group, because their fecal egg counts were nominally higher than that of the treatment group. The control group had only a 0.5% change in PCV. This suggests that our treatment groups’ anemia may have been caused by the Early Bird treatment itself, indicating a possible toxicity. Although, if the control lambs tended to have higher resilience than treatment lambs, on average those with higher FEC could experience higher PCV. Although possible, it seems unlikely given the randomization we used to assign lambs to treatment or control, that those who are more resilient would all be in one group. Katahdins are known for their resistance to gastrointestinal nematodes, and the specific flock where we conducted our study has been selectively bred for increased resistance. However, there likely exists in many Katahdin flocks, individual sheep who despite worm burden, exhibit little to no evidence of anemia. 

While there was a change in PCV for the treatment group there was no noticeable change in FAMACHA© scores from week 0 to week 3. This demonstrates the sensitivity of PCV to quantify anemia over the more subjective FAMACHA© score system. Higher PCV corresponds to a lower FAMACHA©. If a sheep is not showing signs of anemia as indicated by FAMACHA©, they should have a greater number of red blood cells and consequently a higher PCV. The PCV gives a volume percentage while FAMACHA© assigns anemia to five categories. Although we attempted to standardize all the subjective measurements that we took during our study by using a single person to perform the evaluation every time, FAMACHA© (and body condition) scoring are inherently subjective measurements.

One issue we found in the Early Bird product itself was palatability, shown by the greater amounts of refused feed for both treatment groups (Figure 2). The noticeable difference in the two groups’ refusal rates led us to think that the palatability of the Early Bird product could reduce the effectiveness of the product if the animals struggle to eat it. Although we intentionally included data only from those who ate 80% percent or more of their treated feed, slightly lower consumption also may have contributed to the lack of significant findings, especially in our group of ram lambs. We believe the coarseness and novel odor play a role in reducing palatability as does the process of topdressing feed. Future evaluations of this or other herbal dewormers should consider encapsulating the dosage to fully ensure 100% of the necessary herbs are being ingested.

Figure 2. Consumption of Early Bird herbal dewormer, top dressed on sweet feed. Fed to 46 Katahdin lambs over a 2 week period. Percent ingested was based on daily measurements of refused feed.

While a significant change was not identified in fecal egg count reduction it might be that this product is not designed to have a strong effect on worm load comparable to chemical dewormers, but rather any percent reduction is considered to be effective. Depending on the farm this might be something sought after as a preventive and frequently used tool to help manage parasites instead of the cure for heavily parasitized animals.

By:Authors: Nina Brown1, Abigail Slater1

Project Advisors: Dr. James Weber1, and Thomas Hodgman2


[1] College of Earth, Life, and Health Sciences, School of Animal and Veterinary Sciences, University of Maine, Orono, ME

[2] Waldoview Farm, 235 Goshen Rd, Winterport, ME

Acknowledgements

Thank you to Dr. Weber for help with the ANOVA statistical analysis. For providing a centrifuge, McMaster equipment, microscope, and much more. For your time and expertise. 

Thank you to Tom Hodgman for providing the project concept. For allowing us to use your facilities, animals, time, knowledge, and connections.

Thank you to Dr. Joan Burke, USDA ARS Dale Bumpers Small Farms Research Center, for the advice on the experimental design as well as the analysis and identification of the larval species.

Thank you to Dr. Sue Ishaq, School of Animal and Veterinary Sciences, University of Maine, for the support in allowing a dual project and for reviewing all of our reports.


[3] Hair Sheep Times. (2021, November 1). Early Bird Parasite Solutions. https://projects.sare.org/wp-content/uploads/Early-Bird-Parasite-Solutions.pdf

[4] Ardana, Ida & Anthara, Made & Dharmayudha, Anak & Subawa, Anak & Putra, D.K.. (2017). Wudani Leaf Extract (Quisqualis indica Linn) as Traditional Medicine to Control the Incidence of Cattle Worm. Bali Medical Journal. 6. 17. 10.15562/bmj.v6i1.371.

[5] Qin, Qiaojing et al. “Astragalus embranaceus extract activates immune response in macrophages via heparanase.” Molecules (Basel, Switzerland) vol. 17,6 7232-40. 13 Jun. 2012, doi:10.3390/molecules17067232
 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6268577/

[6] Song, Hou-Pan, et al. “Atractylodes Macrocephala Koidz Promotes Intestinal Epithelial Restitution via the Polyamine—Voltage-Gated K+ Channel Pathway.” Journal of Ethnopharmacology, vol. 152, no. 1, Feb. 2014, pp. 163–172 https://doi.org/10.1016/j.jep.2013.12.049

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