Perceptions and actions of Dutch sheep farmers concerning worm infections

Challenges and opportunities for reducing anthelmintic use in ruminant livestock systems: Insights from a sheep farmer survey in France

Today's level of anthelmintic use in livestock production is a major threat to both the livestock industry and the environment. In this context, the research community is looking for ways to equip farmers with preventive and treatment strategies that can decrease livestock-industry dependence on anthelmintics. Production practices for a sustainable control of parasites have been advocated for almost forty years, but farmers' uptake of these practices has been too slow to address the issues at stake. In this paper, we examine the rationales behind the under-adoption of sustainable worm control practices in grassland-based livestock systems. This research builds on 25 semi-structured interviews with dairy sheep farmers in southwestern France. The interview material was analysed via qualitative discourse analysis. We highlight farmers' social representations and rationales underpinning adoption or non-adoption of the 'low anthelmintics use' strategy. We identify six profiles for nematode control according to the way each farmer included treatment and coprology in their on-farm practice. We identify that the low-use strategy has low adoption potential due to its low perceived relative advantage; low perceived trialability; unclear compatibility with previous experiences, needs, and values; and higher complexity than the status quo option. We show that holistic, pro-environmental, and collaborative attitudes are associated with adoption of the low-use strategy. We then discuss ways to improve uptake, such as increased communication, trainings, and farm visits involving farmers, extension agents and veterinarians.

Anthelmintic resistance in ruminants: challenges and solutions

Anthelmintic resistance (AR) is a growing concern for effective parasite control in farmed ruminants globally. Combatting AR will require intensified and integrated research efforts in the development of innovative diagnostic tests to detect helminth infections and AR, sustainable anthelmintic treatment strategies and the development of complementary control approaches such as vaccination and plant-based control. It will also require a better understanding of socio-economic drivers of anthelmintic treatment decisions, in order to support a behavioural shift and develop targeted communication strategies that promote the uptake of evidence-based sustainable solutions. Here, we review the state-of-the-art in these different fields of research activity related to AR in helminths of livestock ruminants in Europe and beyond. We conclude that in the advent of new challenges and solutions emerging from continuing spread of AR and intensified research efforts, respectively, there is a strong need for transnational multi-actor initiatives. These should involve all key stakeholders to develop indicators of infection and sustainable control, set targets and promote good practices to achieve them.

Awareness and control methods of gastrointestinal parasites of merino sheep among farmers from different agro-ecological zones of Lesotho

Background and Aim:

Sheep production plays a crucial role in the economy of Lesotho by increasing economic state of the rural poor. However, gastrointestinal parasites infection is the most limiting factor in sheep productivity and has a highly detrimental effect on the sheep industry. Therefore this study aimed to evaluate farmers’ awareness and understanding of controlling gastrointestinal parasites of merino sheep in four Lesotho agro-ecological zones.

Materials and Methods:

Data were collected using a simple random sampling of 106 farmers in the lowlands, foothills, mountains, and Senqu river valley. Data were analyzed using the Statistical Package for the Social Sciences (version 20.00). Descriptive statistics were employed with cross-tabulations and tested with Chi-square and post hoc tests.

Results:

The majority of farmers (80%) were aware of the gastrointestinal parasites. Most farmers (70%) reported a high prevalence of gastrointestinal parasites and associated it with lamb mortality in summer and autumn. Farmers use anthelmintics for treating gastrointestinal parasites in animals, and 93% of them reported the effectiveness of the drugs. However, more than 80% of farmers routinely use anthelmintics. The results revealed that 81.5%, 66.7%, 80%, and 66.7% of farmers from the lowlands, foothills, mountains, and Senqu river valley, respectively, keep sheep in non-roofed enclosures cleaned only after rains to avoid mud. Communal grazing is used as the main source of animal feeding where different livestock species share the same rangelands. Most farmers (more than 70%) believed that grazing lands were the main source of gastrointestinal parasites transmission.

Conclusion:

Farmers in Lesotho are aware of gastrointestinal parasites and apply control methods to combat the gastrointestinal parasites in merino sheep. However, a need still exists for them to be empowered with skills for improving management systems and the knowledge on how the gastrointestinal parasites behave at different times of the year and in different agro-ecological zones. This will assist them in adhering to the dosing schedule designed by animal health experts.

Treatment against helminths in Norwegian sheep: a questionnaire-based survey

A questionnaire was distributed to 5487 farmers throughout Norway in order to obtain information about management practices regarding helminth infections in sheep. In addition, the farmers' perceptions of helminths and anthelmintic efficacy were investigated. Most farmers (80%) treated prophylactically against nematodes, and 24% also used prophylactic treatment against Fasciola hepatica. Overall, few farmers (11%) used parasitological analysis as a tool to assess the timing of treatment, but rather based it on other factors such as previous experience (70%). In the surveyed sheep flocks, the use of benzimidazoles was reduced from 2018 (52%) to 2019 (47%) (p < 0.01), whereas the use of macrocyclic lactones increased from 2017 (23%) to 2019 (36%) (p < 0.001). Poor anthelmintic efficacy was suspected by 10% of the farmers, and 11% reported that helminths were an increasing problem in their flocks. The majority of farmers (72%) considered their veterinarian as the most important advisor for treatment of parasites, but reported a high level of uncertainty regarding which parasites were present in their flocks, with unknown status most frequently reported for Haemonchus contortus (71.5%). This is probably related to the fact that very few farmers (15%) regularly test their animals for parasites. The present study provides up-to-date information on treatment practices for helminths in Norwegian sheep flocks.

Providing information about triclabendazole resistance status influences farmers to change liver fluke control practices

BACKGROUND

Reports of disease and production losses associated with Fasciola hepatica, the common liver fluke, have increased in recent years. Resistance to triclabendazole, one of the principal veterinary medicines used to prevent losses, has been reported and is now considered widespread in fluke endemic regions of the UK.

METHODS

Thirteen farmers participated in a trial in 2013 and the triclabendazole resistance status was obtained for each farm. Based on these results, a knowledge exchange programme on fluke control was delivered to nearly 100 farmers in the region. In this follow-up study, 11 farmers involved in the original trial, participated in semistructured in-depth qualitative interviews in July 2017.

RESULTS

Overall, participants identified benefits from participating in the 2013 trial, gaining information about triclabendazole resistance on their farms and knowledge about fluke control. The information on their farm's resistance status was a driver for changing their liver fluke control programmes. Factors such as habitual and repetitive behaviours, grazing restrictions due to agri-environmental schemes, economic pressures and climate change were identified that could impede or prevent the adoption of new control strategies.

CONCLUSIONS

The study highlights the significance of resistance to triclabendazole and the impact of knowledge exchange programmes in changing liver fluke control practices.

Anthelmintic resistance and common worm control practices in sheep farms in Flanders, Belgium

In contrast to many other European countries, no data were available on the presence of anthelmintic resistance in gastrointestinal nematodes in sheep in Belgium. A faecal egg count reduction test was performed in 26 sheep flocks in Flanders, Northern Belgium. Results indicated widespread resistance against benzimidazoles (albendazole, fenbendazole and mebendazole), with treatment failure on all 8 farms investigated. Haemonchus contortus and Teladorsagia circumcincta were the predominant species after treatment failure. Amino acid substitutions associated with benzimidazole resistance were detected at the codon positions 167 (8%) and 200 (92%) of the isotype-1 beta tubulin gene in H. contortus, codon positions 198 (47%) and 200 (43%) in T. circumcincta and position 200 (100%) in T. colubriformis. Resistance against macrocyclic lactones (ivermectin, doramectin and moxidectin) was recorded on 7 out of 20 flocks, mainly in H. contortus and T. circumcincta. Treatment failure was also observed for closantel (in combination with mebendazole) and for monepantel, on one farm each. Trichostrongylus spp. were implicated with resistance against monepantel. A questionnaire survey on farm management and worm control measures indicated that worm control was often not sustainable. Ewes and lambs were treated frequently (on average 2.6 and 3.2 times per year), mostly without weighing. Only few sheep farmers (9%) regularly used faecal egg counts to monitor worm infections. Despite the FECRT showing otherwise, most of the farmers perceived the efficacy of anthelmintics as very good (30%) or good (54%).

Detection of Haemonchus contortus on sheep farms increases using an enhanced sampling protocol combined with PCR based diagnostics

An enhanced sampling strategy for detection of gastrointestinal parasites of sheep based on faecal sampling covering approximately 10% of the animals in the flock was evaluated with focus on the major sheep pathogen Haemonchus contortus. We also compared traditional diagnostics based on faecal eggs counts (FEC) by microscopy with DNA detection on frozen faeces samples using a droplet digital (dd)PCR assay. The investigation was carried out in 2018 in 20 conventional and 19 organic sheep flocks in Sweden with between 70 and 250 production ewes. On 76 different sampling occasions a total of 810 individual faecal samples were collected. Samples were pooled in the laboratory into 270 triplets which were examined both by microscopy and a ddPCR assay. On most farms (95%) a minimum of three triplets were investigated, first from the ewes prior to turn-out and later from the lambs after they had been grazing for at least six weeks. Extra information about the Haemonchus status was provided on 48% of the 76 sampling occasions by including more triplets compared with the old sampling strategy applied in Sweden before 2015 based on two triplets per sampling occasion irrespective of flock size. At a farm level H. contortus was identified by microscopy in 22 (56%) of the 39 flocks and by ddPCR it was found in 28 (72%) flocks with the enhanced protocol. There was a substantial agreement between the two diagnostic tests (Cohens kappa = 0.70 ± 0.087). No significant differences in infection levels were observed between the two production systems (conventional and organic) irrespective of the diagnostic method used. However, samples from the ewes were more often Haemonchus positive than those from the lambs indicating that the level of parasite control was in general acceptable. Combined, our results show that Haemonchus infection is widespread throughout Sweden. In conclusion, we have validated a practical tool for sheep producers to assess Haemonchus infection with high precision.

An assessment of worm control practices used by alpaca farmers in Australia

This study aimed to assess current worm control practices used by Australian alpaca farmers with an online questionnaire survey. The questionnaire contained questions about farm demography and general husbandry practices, farmers' knowledge about gastrointestinal nematodes (GINs) and their importance, the use of worm control strategies and anthelmintics, and grazing management. A link for the questionnaire survey was sent to all (n = 954) registered members of the Australian Alpaca Association in July 2015. The response rate for the questionnaire was 25% (239/954). The majority of respondents were from small (≤ 50 alpacas; 64%, 153/239) followed by medium (50-100 alpacas; 24%, 57/239) and large (>100 alpacas; 12%, 29/239) farms. Findings revealed that the majority of respondents kept Huacaya alpacas to produce high-quality fibre and alpacas were usually kept with other domestic ruminants (e.g. cattle and sheep). Although half of alpaca farmers (114/220) perceived that GINs were an important health problem of alpacas, with Haemonchus spp. being the most common nematode, the majority of them (174/220) used anthelmintics for nematode control. Macrocyclic lactones, a commercial combination of four anthelmintics (abamectin, albendazole, closantel and levamisole) and monepantel were the three most commonly used dewormers by Australian alpaca farmers. Although a significant proportion (166/213) of respondents used a quarantine drench for alpacas, very few respondents were aware of strategic deworming and the issue of anthelmintic resistance. Alpaca farmers mostly used anthelmintics at the dose rate recommended for sheep (47%, 79/167) and cattle (9%, 15/167), though some used 1.5 (31%, 51/167) and 2 (13%, 22/167) times the dose rate recommended for sheep. The majority of small herds used anthelmintics at the dose rate recommended for sheep and cattle while medium and large herds used anthelmintics at 1.5 to 2 times the dose rate recommended for sheep. This study provides invaluable insights into the demography of alpaca farms in Australia, husbandry practices used by alpaca farmers and their knowledge about worms and their control, thereby paving the way for developing guidelines for the control of GINs of alpacas.

Alarming levels of anthelmintic resistance against gastrointestinal nematodes in sheep in the Netherlands

In a survey involving 34 sheep flocks spread over the Netherlands anthelmintic resistance (AR), based on a fecal egg count reduction (FECR) test, was determined for six different products. The study was conducted in ewes shortly after lambing during spring 2015. A FECR of less than 90%, indicating presence of AR against one or more nematode genera producing strongylid eggs, was found in 22 of 30 (73.3%) flocks against oxfendazole, 18 of 23 (78.3%) flocks against ivermectin, 15 of 32 (46.9%) flocks against moxidectin, and 2 of 26 (7.7%) flocks against monepantel. No AR was observed against levamisole. If oxfendazole resistance was observed, Haemonchus contortus was involved in 90.5% of the cases. If resistance against ivermectin, moxidectin or monepantel was observed, it invariably involved H. contortus. In the majority of cases resistance was also observed for Teladorsagia circumcincta and/or Trichostrongylus spp, between which no distinction was made in this study. Based on FECR 9 of 15 (60.0%) flocks showed resistance against closantel, which was mainly due to closantel not being effective against most other nematode species than H. contortus. However, in 44.4% of flocks showing reduced FECR it did involve H. contortus as well. Multi-drug resistance (excluding closantel) was found in 16 flocks, of which 8 showed resistance against 2 products, 7 against 3 products and 1 flock showed resistance against 4 products. If resistance against 3 or 4 products was present, there invariably was resistance against both ivermectin and moxidectin. Overall, of the 22 flocks in which both macrocyclic lactones (ML) were tested, 4 (18.2%) showed no resistance against both products, 9 (40.9%) showed resistance against ivermectin only, and 9 (40.9%) showed resistance against both MLs. It is concluded that AR is widespread in sheep in the Netherlands and involves products from all major anthelmintic classes, with possibly the exception of levamisole. It appears that the macrocyclic lactones have lost much of their efficacy against sheep nematodes over the last decade.