The “BIG FIVE” – A South African perspective on sustainable holistic internal parasite management in sheep and goats

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.

Evaluation of a Phytogenic Feed Supplement Containing Carvacrol and Limonene on Sheep Performance and Parasitological Status on a Hungarian Milking Sheep Farm

There is currently worldwide interest in phytogenic feed supplements (PFSs) because they can lead to improved animal production. The scope of the present study was to observe the impact of a feed supplement containing carvacrol (CAR) and limonene (LIM) on the performance and parasitological status of sheep. The feed supplement decreased the plasma levels of β-hydroxybutyrate (p < 0.001), triglycerides (p = 0.014), nonesterified fatty acids (p = 0.021), and fructosamine (p = 0.002) in lactating ewes after 42 days of supplementation, while the average live weight (p = 0.002) and average daily weight gain (p = 0.001) of their twin suckling lambs increased significantly by the end of the study. In another experiment, fattening lambs fed the same supplement showed a decrease in fecal egg number of gastrointestinal nematodes (p = 0.02) but no differences in live weight, average daily gain, or mean number of Haemonchus contortus nematodes in the abomasum. The results highlighted that the inclusion of carvacrol and limonene in the feed of lactating ewes effectively increased the weight gain of the suckling lambs, presumably due to the ewes' improved energy, but further studies are needed to elucidate the effects of carvacrol and limonene against gastrointestinal parasites.

Short communication: A practical farm-based trial to compare ewe nematode control strategies in peri-parturient ewes

The focus of gastro-intestinal parasite control in the sheep industry is increasingly on finding a balance between maintaining productivity of the flock whilst minimising selection for anthelmintic resistance to preserve anthelmintic efficacy for the future. Periparturient ewes represent the major source of gastro-intestinal parasites for growing lambs and are therefore a priority for parasite control. This study examines the impact on ewe faecal egg counts (FECs), lamb FECs, lamb daily live weight gains (DLWGs) and pasture larval counts of treating groups of ewes two weeks prior to lambing with either, a long-acting moxidectin treatment, short-acting doramectin or control. Six groups of twenty ewes were allocated to individual paddocks, two groups allocated to each treatment, and weekly faecal sampling was performed throughout from the ewes and from six weeks after the start of lambing in the lambs. Treatment group was found to have a significant effect on both ewe FEC (p<0.001) and lamb FEC (p = 0.001) with the group receiving the long-acting anthelmintic having the lowest ewe and lamb FECs. There was no significant effect on the DLWGs of the lambs. Pasture larval counts at the end of the study period were lowest in the long-acting wormer treatment group. The use of long-acting moxidectin may be helpful as part of a parasite control programme by reducing the worm burdens of ewes and their lambs, decreasing the number of anthelmintic treatments required in that year and by reducing pasture contamination for those sheep which will graze the pasture in the next year. However, like all anthelmintics, its use should be judicious to avoid selection for resistance.

Refugia-Based Strategies for Parasite Control in Livestock

Refugia-based strategies are intended to help slow the development of anthelmintic resistance by providing a population of parasites that are not exposed to the treatment. Evidence from field studies is lacking. There is no single way to incorporate refugia into a parasite control program. There are many options available varying greatly in complexity and practicality, and none are suitable for all situations. Incorporating refugia into production systems typically requires a change in farmer mindset and greater input of time, labor, and/or technology, but is necessary to help preserve anthelmintic efficacy and promote sustainable animal production systems.