Dung Beetle Project - Final Report

Introduction:

VetSalus consultant, Anuschka Marsman, has been working with a group of farmers in west Wales on a fascinating project to monitor worming routines and dung beetle populations. VetSalus has reported on this project before. (Dung Beetle and Anthelmintic Reduction - Project Update/ Regenerative farming, dung beetles and anthelmintic treatment - Project Overview)  She has now produced a final report and has kindly permitted us to publish her findings. If you would like further information on this project please contact Anuschka at : [email protected]

1. Background

The aim of the project was to change behaviour with respect to the use of anthelmintics through peer-to-peer learning by attending meetings with discussion and education. As well as lungworm, youngstock need to build up immunity to GastroIntestinal Nematodes (GIN) during grazing and this takes 8 months of exposure. Using as little anthelmintics as possible and as much as necessary, is of vital importance to ensure exposure criteria are met. 

Dung beetles are vitally important insects which improve the water quality and structure of soil. They reduce the parasite burden in the dung by a third as well as nuisance fly populations and remove dung pats altogether. No dung removal will result in 16% loss of grazing area. It has been estimated that dung beetles save the UK cattle industry £367 million per year through the provision of ecosystem services.

In the UK there are 60 species of dung beetles, approximately 50% of which are nationally scarce or listed as threatened to some degree. The use of certain anthelmintics is linked to reduced abundance, diversity and functioning of dung beetles.

2. Material and Methods:

Thirty-one dairy farmers and First Milk Members that are using ProStock Vets for their veterinary services took part in the Dung Beetle Project. 

The project was funded through contributions from Farming Connect, the farmers, First Milk and ProStock Vets.

The project ran from March until December 2024; Three meetings and three visits were scheduled for farmers. Farmers were encouraged to use the lungworm vaccine before turnout. The meetings facilitated education, discussion, and peer to peer learning. The visits were part education and part providing monitoring tools. Two dung beetle assessments were carried out during the visits. All participants had unlimited FECs. General communications happened via a dedicated WhatsApp group. All other communications happened 1-to-1 with the farmer. 

Monthly pooled faecal samples were collected by the farmer and taken into ProStock Vets the same day or refrigerated and taken in the following day. The samples were analysed for GIN-eggs using FECPAK second generation. The turnaround time for results was 24 hours. If the FEC was greater than zero, another sample was submitted after two weeks. Other parameters, more subjective, like how well animals looked and the absence of coughing were also used in the decision-making process on whether to worm or not. 

Fluke-antibody, adult-lungworm antibody and pepsinogen testing were done soon after housing in the autumn of 2024 (Table 1). 

The bulk milk and bloods were analysed by Liverpool University. An ELISA test was used for the testing of lungworm (Dictyocaulus viviparus) and fluke (Fasciola hepatica) in bulk milk and serum.

The pepsinogen testing was conducted by SRUC, a cut-off of 1.5 units has been used.

Table 1. Samples taken on every farm.

3. Results

Fifteen out of thirty-one farmers opted to vaccinate for lungworm. In the previous year only three were vaccinating for lungworm, an increase of 400% in lungworm vaccine sales. 

There has been an 87% reduction in the incidence of worming with Macrocyclic Lactone (ML – Group 3 wormers) on the farms that used the lungworm vaccine (Huskvac, MSD), see Table 3. Overall, there was a 65% reduction for all farms, see Table 2.

Table 2. All farms (n=31), number of times wormed per group in 2023 and 2024 according to the questionnaire.

Table 3.  Huskvac-using farms (n=15), number of times wormed per group in 2023 and 2024 according to the questionnaire.

Of the sixteen farms that did not vaccinate for lungworm, ten showed exposure to lungworm in their first grazers.

Out of the thirty-one farms, twenty-one showed exposure to fluke in the samples from the first grazers, ten didn’t. Out of the thirty-one farms, twenty-two were positive for fluke antibodies in their bulk milk, nine were negative.

Half of all the farms had one or more serum samples with pepsinogen levels over 1.5 units. This was not related to the frequency of worming or absence thereof.

4. Economics

Case scenario 

5. Discussion

The project has been successful in raising awareness of the importance of dung beetles and on the importance of building up immunity against GIN infections in youngstock. Far less farmers applied wormers before or at turnout and most were guided by FEC during the grazing season as to whether to worm or not. Farmers were encouraged to take note of pasture sward length when cattle were turned in and out as most of the nematode eggs are harboured at the bottom 10 cm due to moisture and temperature constraints. They were also encouraged to assess the pasture risk with first grazers ideally grazing silage aftermath or reseeded pasture. 

Pepsinogen levels were determined within two weeks after housing before the parasites underwent hibernation. If one animal had elevated levels the advice was to worm the whole group with a short-acting ML (Group 3) wormer. As the animals were housed, no residues ended up in fresh dung on the land. Dung beetles do nothing with dung that is not fresh like slurry manure. 

All FECs done on adult cows showed zero to extremely low faecal egg counts which did not justify worming. In addition to this, antibodies levels for adult-lungworm-sperm in bulk milk were negative for all farms.

Using lungworm vaccine in the build-up of immunity to lungworm will reduce anthelmintic use as was clearly shown in this project. The damage done by an outbreak of lungworm disease can be substantial and is also of major welfare concern. Many farms did have lungworm present and the economics are favourable for using the vaccine. 

As far as dung beetle populations are concerned, stopping killing dung beetles would be a start. The highest dung beetle scores were found on the farms that historically (2023) used the least anthelmintics. Less and a more responsible use of anthelmintics will therefore have a positive impact but populations will take years to recover as many species only reproduce once or twice a year. 

Using anthelmintics that are less toxic to dung beetles (figure 1) will make a significant difference and specifically the continuous-release, long-acting formulations of doramectin are especially detrimental. These can also interfere with the build-up of immunity as the 8 months of exposure are not necessarily reached. The environmental costs have not been quantified but are well documented.

Figure 1. If you have to use chemicals, then use those less toxic to dung beetles when cattle are out on pasture. Dr Sarah Beynon, the bug farm.

A special thank you to the sponsors, Farming Connect, First Milk, ProStock Vets and the farmers. John-Graham Brown and his team at Liverpool University for helping with the testing. The vets and support staff in ProStock Vets that took part or helped in the project.