Sustainable Approaches to Parasite Control in Ruminant Livestock

Multiple-species resistance to avermectin anthelmintics on beef cattle farms in Georgia, USA

Anthelmintic resistance (AR) in gastrointestinal nematodes (GIN) is a worldwide problem in all livestock production systems. Several prevalence studies performed internationally demonstrate that AR in cattle parasites is a growing problem; however, there are no published studies on prevalence in the United States (USA). In this study, we performed fecal egg count reduction tests (FECRT) on twelve cow-calf farms in Georgia, USA. On all farms the efficacy of eprinomectin pour-on (Eprinex®) and doramectin injectable (Dectomax®) was tested individually, as well as a combination treatment of doramectin injectable with oral fenbendazole (Safe-guard®). Fenbendazole was also tested individually on 7 farms, and long-acting eprinomectin (LongRange®) on one farm. FECRTs were performed, analyzed and interpreted following the 2023 WAAVP guidelines. Coprocultures were conducted to assess genus-specific efficacy. Overall, 100 % (12/12) and 75 % (9/12) of farms had resistance to at least one of the avermectin drugs tested in one or more GIN species, respectively. FECR ranged from 14.0 % to 96.8 % (mean=61.81 %) and 8.9-97.9 % (mean=66.87 %) for eprinomectin and doramectin, respectively; this difference was not significant (P = 0.924). In contrast, FECR for fenbendazole was high on all 7 farms tested, with just one farm demonstrating a low level of resistance. The combination treatment of doramectin plus fenbendazole was effective on all 12 farms (mean FECR=98.75 %), being significantly higher than for eprinomectin or doramectin (P≤0.001). Where coproculture data were sufficient to evaluate genus-specific reduction, resistance to Cooperia spp., Haemonchus spp. and Ostertagia spp. was present on 11/12 (92 %), 6/8 (75 %), and 4/10 farms (40 %), respectively. These data demonstrate that resistance to avermectin drugs is highly prevalent in Cooperia, Haemonchus, and Ostertagia on beef farms in Georgia. Though these data represent just one southern state, given the high level of movement of cattle in the USA, AR in GIN of cattle is likely to be highly prevalent throughout not only the southern USA, but across much of the country.

Ethnoveterinary practices for treating parasitic diseases in domestic animals among Kyrgyz farmers

While modern veterinary medicine offers effective treatments, traditional ethnoveterinary practices persist among many farming communities, reflecting centuries-old knowledge and cultural beliefs. This study aimed to document ethnoveterinary remedies and their methods of preparation and application, for treating various parasitic diseases in domestic animals used by Kyrgyz farmers. Data on plant, animal and mineral-based remedies, as well as chemicals used for these purposes, were collected through interviews with 173 dialogue partners (DPs). A total of 3403 use reports (URs) were recorded, indicating 1866 plant-based remedies (2114 URs; 62.1 %), 11 animal-based remedies (693 URs; 20.4 %), 4 mineral-based remedies (236 URs; 6.9 %) and 6 chemicals (360 URs; 10.6 %) used as antiparasitic agents by Kyrgyz farmers. The preparation of 991 homemade single species herbal remedy reports (HSHRs) and 875 homemade mixed species herbal remedy reports (HMHRs) involves the utilisation of 56 plant species belonging to 20 families. Helminthiasis was the most frequently mentioned by DPs (1697 URs; 49.9 %), followed by mange (965 URs; 28.6 %), external parasites (594 URs; 17.4 %) and myiasis (maggots in wounds) (89 URs; 2.6 %), other myiasis (58 URs; 1.7 %). The highest number of URs was observed for cattle (1221 URs; 35.9 %), sheep (733 URs; 21.5 %) and horses (696 URs; 20.4 %), followed by goats (299 URs; 8.8 %), dogs (201 URs; 5.9 %), donkeys (170 URs; 5 %), chickens (59 URs; 1.7 %) and turkeys (24 URs; 0.7 %). All the remedies presented have significance for local residents, who previously had exclusive access to these skills. However, many of the documented remedies require confirmation using modern technologies.

Genetic parameters and single-step genome-wide association analysis for trematode (Fasciola hepatica and Calicophoron/Paramphistomum spp.) infections in German dairy cows

Infections with the liver fluke (Fasciola hepatica) cause economic losses in cattle production worldwide. Also, infections with rumen flukes (Calicophoron/Paramphistomum spp.) are gaining importance in grazing cattle in Europe. However, increasing resistance of helminth parasites against anthelmintics and limitations in treatment emphasize the need for alternative breeding approaches. This study included 1602 dairy cows kept on 29 farms with 2423 observations for F. hepatica and Calicophoron/Paramphistomum spp. egg counts per gram faeces (EPG). The EPGs were binary defined (infected: EPG > 0; non-infected: EPG = 0) and logarithmically transformed. The pedigree included 7939 cows. Genotypes (777 k) were available for 214 cows. A single-step GBLUP (ssGBLUP) model was applied to estimate genetic parameters for infection traits. Genomic breeding values from ssGBLUP were used in a single-step genome-wide association study (ssGWAS) to identify genetic variants associated with helminth infections. The heritability for liver fluke infections was up to 0.09, and up to 0.34 for rumen fluke infections. The genetic correlations between liver and rumen fluke infections ranged from 0.49 to 0.53, indicating that breeding for improved resilience to both helminth taxa is possible simultaneously. The ssGWAS revealed four SNPs for liver fluke infections on BTA 5, 13, 26 and 29, and 17 SNPs for rumen fluke infections on BTA 3 and 23. The SNPs for liver fluke infections were annotated to 12 potential candidate genes, most of which involved in liver fibrosis and immunity. The LRRC8B gene was found to be involved in host-rumen fluke interactions.

Epidemiology of caprine gastrointestinal nematodes and associated efficacy of anthelmintic drugs in Punjab districts, India

Gastrointestinal parasites pose a serious threat to sustainable small ruminant farming worldwide including Indian subcontinent and the control primarily relies on administration of anthelmintic drugs. A continuous surveillance regarding their distribution and efficacy of commonly used anthelmintics is essential for their effective control in a region. In the present study, faecal samples (n = 1962) were collected from goats of 17 districts of Punjab state, India and examined by qualitative and quantitative examination methodologies. An overall prevalence of 93.62% was recorded for gastrointestinal parasitism with strongyles being the most prevalent (88.99%), followed by coccidia (65.34%), Moniezia spp. (16.62%), Trichuris spp. (9.38%), Strongyloides spp. (7.65%) and trematodes (Fasciola spp. and amphistomes) being least prevalent (0.02%). The quantitative analysis revealed 48.05, 14.43 and 37.51% goats with low, moderate and heavy gastrointestinal nematode infection (GIN), respectively, while faecal culture examination revealed six genera of GINs as Haemonchus (75.94%) being the predominant, followed by Trichostrongylus (16.44%), Oesophagostomum (4.85%), Bunostomum (1.65%), Ostertagia (0.77%) and Cooperia (0.33%). The logistic regression analysis revealed that risk factors viz. agroclimatic zones, season, sex and deworming status were significantly associated with prevalence of gastrointestinal parasites. The status of efficacy against fenbendazole, levamisole and ivermectin were also analysed by in-vivo faecal egg count reduction test at 17 goat farms. The overall percent efficacy as mean ± SE (range) for fenbendazole, levamisole and ivermectin was estimated at 55.97 ± 4.78% (18.92-92.44%), 51.74 ± 4.77% (11.20-77.86%) and 62.63 ± 4.66% (32.41-98.63%), respectively. The results revealed resistance against fenbendazole, levamisole and ivermectin on 100%, 100% and 94.1% farms, respectively, whereas, in-vitro tests (egg hatch test and larval developmental assay) revealed resistance as 70.6%, 93.8% and 73.3%, respectively. The high prevalence of GINs in Punjab state can be correlated with the resistance recorded against all commonly used anthelmintics and warrants exploration of non-chemical mitigation strategies for effective control. The findings of the present study would be of immense help for the policy-framers/field veterinarians/extension worker etc. in formulation and implementation of effective control measures for worm management through judicious use of the anthelmintics.

Nematophagous fungi to controlling gastrointestinal nematodes in small ruminants: A systematic review

Gastrointestinal nematode infections are responsible for production losses in small ruminant worldwide. Moreover, anthelmintic resistance has increased mortality. New sustainable control strategies have been developed to overcome this problem. Biological control has emerged as a new trend with the recent market introduction of bioproducts. This systematic review aimed to analyze publications on the production of formulations and bioproducts based on helminthophagous fungi used to control gastrointestinal nematodes in sheep and goats, and to survey patents filed with this recommendation. The guidelines PRISMA 2020 were used, searching from 2004 to 2024. The following scientific databases were used: Springer, Science Direct, SciELO, Web of Science, Google Scholar, CAPES Journals and PubMed. The search for patents was carried out using the PATENTSCOPE database. Duplicate articles; review/opinion articles; studies in other animal species; studies without approval by an ethics committee; and tests performed only under in vitro conditions were excluded. Nine studies were included, six of which tested formulations and three tested bioproducts. Duddingtonia flagrans was most frequently included (8), being found in the two available bioproducts. Brazil shows the largest number of studies in the area (5). Sheep were more frequent (7) than those with goats (2). Reduction percentages ranged from 6 % to 96.6 %. Regarding patent searches, only three were found, two of which were for D. flagrans formulations and one for a utility model with Arthrobotrys drechslen. D. flagrans is the nematophagous fungus with the greatest potential to produce bioproducts in the biological control of gastrointestinal nematodes in small ruminants.

Impacts of birth season and production system on gastrointestinal parasitism and growth in Katahdin lambs

Gastrointestinal nematode (GIN) infection adversely affects the performance and well-being of forage-based sheep throughout the world. The study objectives were to estimate longitudinal differences between birth seasons and production systems for lamb postweaning growth and indicators of GIN infection. Data were collected on Katahdin lambs within a single flock from 2006 to 2022. Lambs were born in either the winter or fall and reared in conventional or certified organic production systems. Four sub-flocks were defined as the combination of birth season and production system (winter-conventional = W-C, n = 1766; winter-organic = W-O, n = 190; fall-conventional = F-C, n = 846; and fall-organic = F-O, n = 189). All lambs were naturally infected with GIN from previously grazed pastures, weaned at approximately 60 d of age, and remained on pasture throughout the postweaning phase. At approximately 90, 120, and 150 d of age lamb body weight (BW) was recorded, and fecal egg count and blood packed cell volume (PCV) were quantified. Fecal egg count was log-transformed (LFEC) prior to analyses. Traits were initially analyzed within collection timepoint to compare all 4 sub-flocks. Final BW at 150 d and LFEC and PCV throughout the postweaning phase were similar between conventional and organic lambs born in the same season. Repeated measures models were then used to analyze records from W-C and F-C lambs over time. The collection timepoint × deworming treatment × sub-flock interaction effect was significant for all traits (P < 0.01). Within lambs that did not require deworming, no difference in BW between birth seasons was observed. However, LFEC trends for untreated F-C and W-C lambs were nearly exact opposite of one another, being greater for F-C at 90 d, (P < 0.01) not different at 120 d, and greater for W-C at 150 d (P < 0.01). Additionally, PCV of untreated F-C lambs was lower at 90 d but greater at 120 and 150 d than untreated W-C lambs (P ≤ 0.04). This was the first study conducted in the U.S. to compare longitudinal performance between lambs born in different seasons and reared in different production systems. Under the conditions of this study, organically managed lambs had similar performance to their conventionally managed counterparts. However, large differences in GIN infection risk over time existed between birth seasons and deworming regimens which have important implications for producer management decisions and genetic improvement programs.

Anthelmintic activity of three selected ethnobotanical plant extracts against Strongyloides venezuelensis

The agropastoral farmers have employed Turraea vogelii(TVL),Senna podocarpa(SPL), and Jaundea pinnata (JPL) leaves for treating various diseases, including intestinal parasites in livestock and the human population in Nigeria. Gastrointestinal nematodes are highly significant to livestock production and people's health, and natural products are interesting as sources of new drugs. In this study, we evaluated the effectiveness of extracts derived from these plants in treating parasitic infections using third-stage infective larvae (L3) of Strongyloides venezuelensis. We obtained crude extracts using n-gexane (Hex), ethyl acetate (Ea), and methanol (Met). The extracts were analyzed for their phytochemical composition, and their ability to prevent hemolysis were tested. The mean concentrations of total phenols in SPL Hex, SPL Ea, and SPL Met were 92.3 ± 0.3, 103.0 ± 0.4, and 128.2 ± 0.5 mg/100 g, respectively. Total tannin concentrations for JPL Ea, SPL Ea, SPL Hex, and TVL Hex were 60.3 ± 0.1, 89.2 ± 0.2, 80.0 ± 0.1, and 66.6 ± 0.3 mg/100 g, respectively. The mean lethal concentration (LC50) at 72 h for JPL Ea 39 (26-61) μg/mL. SPL Ea was 39 (34-45) μg/mL, and TVL Hex 31 (26-36) μg/mL. The antiparasitic activities of the extracts against L3 were dose- and time-dependent. All the extracts were slightly hemolytic to the erythrocytes. In this study, the plant extract tested demonstrated significant anti-S. venezuelensis activity. These phytobotanical extracts could be used to create formulations for the potential treatment of helminthiasis in animals and humans.

A systematic review on products derived from nematophagous fungi in the biological control of parasitic helminths of animals

Nematophagous fungi have been widely evaluated in the biological control of parasitic helminths in animals, both through their direct use and the use of their derived products. Fungal bioproducts can include extracellular enzymes, silver nanoparticles (AgNPs), as well as secondary metabolites. The aim of this study was to conduct a systematic review covering the evaluation of products derived from nematophagous fungi in the biological control of parasitic helminths in animals. In total, 33 studies met the inclusion criteria and were included in this review. The majority of the studies were conducted in Brazil (72.7%, 24/33), and bioproducts derived from the fungus Duddingtonia flagrans were the most commonly evaluated (36.3%, 12/33). The studies involved the production of extracellular enzymes (48.4%, 16/33), followed by crude enzymatic extract (27.2%, 9/33), secondary metabolites (15.1%, 5/33) and biosynthesis of AgNPs (9.1%, 3/33). The most researched extracellular enzymes were serine proteases (37.5%, 6/16), with efficacies ranging from 23.9 to 85%; proteases (31.2%, 5/16), with efficacies from 41.4 to 95.4%; proteases + chitinases (18.7%, 3/16), with efficacies from 20.5 to 43.4%; and chitinases (12.5%, 2/16), with efficacies ranging from 12 to 100%. In conclusion, extracellular enzymes are the most investigated derivatives of nematophagous fungi, with proteases being promising strategies in the biological control of animal helminths. Further studies under in vivo and field conditions are needed to explore the applicability of these bioproducts as tools for biological control.

Adapting the in vitro rumen incubation method to evaluate the effect of a plant extract on the exsheathment inhibition of Haemonchus contortus infective larvae

This study adapted the in vitro rumen incubation (IVRI) method to evaluate the biological activity of a Gymnopodium floribundum leaves extract against the exsheathment of Haemonchus contortus infective larvae (L3), and to determine the role of plant polyphenols on the biological activity. The incubation protocol followed the IVRI method, adding polyethylene glycol (PEG) as a polyphenol-blocking agent. The L3 were incubated in ruminal liquor (RL), ruminal liquor with PEG (RL+PEG), ruminal liquor with G. floribundum extract (RLE), and ruminal liquor with G. floribundum extract and PEG (RLE+PEG). Incubation condition controls included phosphate buffered saline (PBS), PBS with PEG (PBS+PEG), incubation medium (without ruminal liquor) (IM), and incubation medium with PEG (IM+PEG). The L3 were recovered after incubation times of 0, 1, 3, 6, 9, and 24 h (39 °C). The respective L3 exsheathment kinetics were estimated for the different treatments (RL, RL+PEG, RLE, and RLE+PEG) using Log-Logistic models. The parameters of the different models were compared to determine the impact of the extract, with or without PEG, on the L3 exsheathment kinetics. The exsheathment in PBS and PBS+PEG remained < 2.71% at each incubation time. The exsheathment in IM and IM+PEG reached 13.58% and 17.18% at 24 h, respectively. The exsheathment percentages for RLE were lower than those for RL at 3, 6 and 9 h of incubation. The inflection point, indicating the time required to reach 50% of the maximal exsheathment (T50), was the only parameter that differed between the ruminal liquor models. The T50 in RLE (7.106 h) was higher than the values obtained for RL (5.385 h) and RL+PEG (4.923 h) (99.99% probability of being different). Such delay resulted in a reduction of exsheathment in RLE of 62% at 3 h, 38% at 6 h, and 12% at 9 h, relative to RL values. When PEG was added with the extract (RLE+PEG), the T50 (5.045 h) was similar to that of RL and RL+PEG. The IVRI method was adapted as an in vitro rumen exsheathment test (IVRET). The IVRET showed that H. contortus L3 exposed to G. floribundum extract delayed their exsheathment kinetics at different time points. The exsheathment delay was attributed to the polyphenol content of the extract.

Anthelmintic Activities of Extract and Ellagitannins from Phyllanthus urinaria against Caenorhabditis elegans and Zoonotic or Animal Parasitic Nematodes

The aerial parts of Phyllanthus urinaria are used in traditional medicine in West Africa against helminthiasis, but their anthelmintic potential has not been evaluated until now. Within the current study, a hydroacetonic extract (AWE) and fractions and isolated ellagitannins from P. urinaria were, therefore, tested in vitro against Caenorhabditis elegans and the larvae of the animal parasites Toxocara canis, Ascaris suum, Ancylostoma caninum, and Trichuris suis. Compounds 1:  - 13: , mainly representing ellagitannins, were isolated using different chromatographic methods, and their structures were elucidated by HR-MS and 1H/13C-NMR. AWE exerted concentration-dependent lethal effects (LC50 of 2.6 mg/mL) against C. elegans and inhibited larval migration of all animal parasites tested (T. suis L1 IC50 24.3 µg/mL, A. suum L3 IC50 35.7 µg/mL, A. caninum L3 IC50 112.8 µg/mL, T. canis L3 IC50 1513.2 µg/mL). The anthelmintic activity of AWE was mainly related to the polar, tannin-containing fractions. Geraniin 1: , the major ellagitannin in the extract, showed the strongest anthelmintic activity in general (IC50 between 0.6 and 804 µM, depending on parasite species) and was the only compound active against A. caninum (IC50 of 35.0 µM). Furosin 9: was least active despite structural similarities to 1: . Among the parasites tested, Trichuris suis L1 larvae turned out to be most sensitive with IC50 of 0.6, 6.4, 4.0, 4.8, and 2.6 µM for geraniin 1: , repandusinic acid A 3: , punicafolin 8: , furosin 9: , and phyllanthusiin A 10: , respectively.

The diversity and quality of forages and their potency as herbal anthelmintic for swamp buffalo in Brebes District, Central Java

Background and Aim

Swamp buffaloes play an important role in the rural economy of Indonesia. They consume various forages during their grazing time, including those with anti-parasitic potential. However, the information about the type and quality of forages and their potential as a natural anthelmintic for swamp buffalo is very limited. This study aimed to identify the diversity, quality, and anthelmintic potency of forages consumed by swamp buffaloes reared in Bantarkawung Subdistrict, Brebes District, Central Java Province, Indonesia.

Materials and Methods

Samples of forages were obtained during three observation periods of the study, with a 12-week interval between each period. Forage diversity was evaluated by identifying its consumption by swamp buffaloes during their grazing activity in the field and feeding time in their shed. The quality of forages was analyzed using proximate analysis to measure their dry matter (DM), crude fiber (CF), crude protein (CP), crude fat (CFat), and ash contents. This is followed by the calculation of their total digestible nutrient based on the proximate analysis results. Botanical composition analysis was then conducted to measure the predominance of forages consumed by the livestock during their grazing activity. Literature reviews were carried out to explore forage's anthelmintic activity.

Results

The results showed that swamp buffaloes consume nine species of forage in the shed and 47 in the grazing area, including nine legumes, 18 grass, and 20 others. Swamp buffaloes consumed forages of lower quality, which contained high CF contents and varying levels of other nutrients below their daily nutritional needs. The grazing activity allowed swamp buffaloes to consume a higher variety of forages with better nutritional quality, thereby enabling them to meet their nutritional needs. Legumes and other forages served as the major protein sources, providing CP of 20.03% DM and 11.53% DM, and CF levels of 17.01% DM and 20.35% DM, respectively. The results also showed that the consumption of these forages increased during the rainy season. The predominant species of legumes consumed were Leucaena leucocephala and Acacia spp., while Alternanthera sessilis and Merremia umbellata were the predominant species of other forages. A total of 13 of the 47 species could potentially be used as natural anthelmintic due to their secondary metabolites, namely, tannin, flavonoid, saponin, terpenoid, diterpenoid, and mimosine. These compounds exert anthelmintic effects by inhibiting egg-hatching and larval development, as well as damaging the surface structure of both larvae and adult worms, ultimately leading to the death of the parasites.

Conclusion

Overall, swamp buffaloes consumed more variety of forages during grazing compared to when they were kept in sheds. While the low-variety and low-quality forages provisioned for swamp buffaloes in their shed resulted in a low nutrient intake below their daily requirement. Furthermore, daily grazing activities allowed swamp buffaloes to fulfill and supplement their need by consuming a variety of grasses, legumes, and other forages in their respective grazing areas. Some of these forages also have the potential to become natural anthelmintic because they contain secondary metabolites, such as tannins, flavonoids, saponins, terpenoids, diterpenoids, and mimosine.

Extruded urea levels in lamb supplementation in rainy tropical savanna conditions: the triad host-gastrointestinal nematodes-environment

The objective of this study was to evaluate the influence of increasing levels of extruded urea (EU, Amireia®) in the diet of lambs naturally infected by gastrointestinal nematodes on the interactions in the host-pasture-soil components in edaphoclimatic conditions of the tropical rainy savanna. A total of 60 Texel lambs with a mean initial weight of 20.7 ± 0.87 and mean age of 2.5 ± 0.70 months were distributed in a completely randomized design, in five treatments consisting of different levels of EU supplementation viz., 0, 6, 12, 18, and 24 g 100 kg^-1 live weight (LW). The performance of lambs, parasitological variables, gastrointestinal nematodes (NGIs), and larvae recovery in pasture and soil were evaluated. The highest animal performance was observed in animals that received 0 to 18 g kg^-1 LW (146.0 g day^-1) and the lowest in animals supplemented with 24 g kg^-1 LW (81.0 g day^-1) of EU. The body condition score (BCS) was similar in the animals (P > 0.05). Parasitic infection did not differ as a function of EU level (P > 0.05). Eggs of Haemonchus spp., Trichostrongylus spp., Cooperia spp., and Oesophagostomum spp. were found. The largest amount of larvae in the L1/L2 and L3 stages was recovered in the pastures occupied by the animals that received supplementation 0 g kg^-1 LW of EU (750 larvae), the smallest in those that the animals received 6 g 100 kg^-1 LW of EU (54 larvae). The presence of larvae in the L1/L2 stages changed significantly (P < 0.05) in the soil; in the other stages, it did not differ in the soil. Increasing levels of extruded urea do not influence the eggs per gram of feces (EPG) count. The 0 to 18 g 100 kg^-1 LW level maintains animal performance, BCS and FAMACHA^©. There is less dispersal of NGI larvae in pasture and soil when EU levels increase in the edaphoclimatic conditions of the rainy tropical savannah, which suggests that this supplement can be implemented in the diet of beef lambs, in addition to to be a lower cost nitrogen source.

Classification Performance of Machine Learning Methods for Identifying Resistance, Resilience, and Susceptibility to Haemonchus contortus Infections in Sheep

This study investigated the feasibility of using easy-to-measure phenotypic traits to predict sheep resistant, resilient, and susceptible to gastrointestinal nematodes, compared the classification performance of multinomial logistic regression (MLR), linear discriminant analysis (LDA), random forest (RF), and artificial neural network (ANN) methods, and evaluated the applicability of the best classification model on each farm. The database comprised 3654 records of 1250 Santa Inês sheep from 6 farms. The animals were classified into resistant (2605 records), resilient (939 records), and susceptible (110 records) according to fecal egg count and packed cell volume. A random oversampling method was performed to balance the dataset. The classification methods were fitted using the information of age class, the month of record, farm, sex, Famacha© degree, body weight, and body condition score as predictors, and the resistance, resilience, and susceptibility to gastrointestinal nematodes as the target classes to be predicted considering data from all farms randomly. An additional leave-one-farm-out cross-validation technique was used to assess prediction quality across farms. The MLR and LDA models presented good performances in predicting susceptible and resistant animals. The results suggest that the use of readily available records and easily measurable traits may provide useful information for supporting management decisions at the farm level.

Variability in the Response against Teladorsagia circumcincta in Lambs of Two Canarian Sheep Breeds

The increasing resistance to anthelmintics has necessitated the exploration of alternative control strategies of gastrointestinal nematode (GIN) infections. A sustainable option is genetic selection based on differences in susceptibility to GIN infection between and within breeds of sheep. Here, three-month-old Canaria Hair breed (GIN-resistant) and Canaria Sheep breed (GIN-susceptible) showed no significant between-breed differences after trickle infection with Teladorsagia circumcincta, whereas considerable individual variability was found in both breeds. Next, data from lambs of both breeds were used to explore the relationships between parasitological variables and T. circumcincta-specific IgA levels, local immune cell populations, and abomasal lymph node gene expression to understand the possible mechanisms underlying resistance. Mucosal IgA levels as well as numbers of globular leukocytes and MHC-II⁺ cells were associated with protection. Analysis of lymph node gene expression revealed the associations between lower parasite numbers and cumulative fecal egg counts and several immune pathways, such as leukocyte cell adhesion, activation and differentiation of T cells, in particular CD4⁺ and IL-4 production. The data obtained here may inform on the relationship between phenotypic resistance variability and protective responses at the humoral, cellular, and transcriptomic levels, thus contributing to identifying immune responses in young lambs that could be used as markers for selection.

Condensed tannins act as anthelmintics by increasing the rigidity of the nematode cuticle

Tannins and tanniferous plant extracts have been discussed as sustainable means for helminth control in the past two decades in response to a dramatic increase of resistances towards standard anthelmintics. While their bioactivities have been broadly investigated in vitro and in vivo, less is known about their mode of action in nematodes, apart from their protein binding properties. In the current study we therefore investigated the impact of a phytochemically well characterized plant extract from Combretum mucronatum, known to contain procyanidins as the active compounds, on the model organism Caenorhabditis elegans. By different microscopic techniques, the cuticle was identified as the main binding site for tannins, whereas underlying tissues did not seem to be affected. In addition to disruptions of the cuticle structure, molting defects occurred at all larval stages. Finally, an increased rigidity of the nematodes' cuticle due to binding of tannins was confirmed by force spectroscopic measurements. This could be a key finding to explain several anthelmintic activities reported for tannins, especially impairment of molting or exsheathment as well as locomotion.

Copper oxide wire particles effective against gastrointestinal nematodes in adult alpacas during a randomized clinical trial

OBJECTIVE

To determine whether copper oxide wire particles (COWP) administered as an oral bolus effectively decrease fecal gastrointestinal nematode (GIN) egg counts in adult alpacas.

ANIMALS

57 adult alpacas.

PROCEDURES

A double-blind clinical trial was performed during the months of April through August 2019. Adult alpacas enrolled in the trial were administered 2 g of COWP or a placebo control capsule PO on day 0 and day 45. On day 0 and at 15-day intervals, fecal samples were collected, and Modified McMaster fecal egg counts (FEC) were performed as well as physical examinations, including FAMACHA scoring and body condition scoring (BCS). Hematocrits were measured in 30-day intervals (days 0, 30, 60, and 90). Results were compared across groups.

RESULTS

A significant decrease in mean FEC was observed in the COWP-treated group over time, compared with the placebo group. Mean BCS, FAMACHA score, and Hct did not differ significantly between groups. No clinical evidence of copper toxicosis was observed.

CLINICAL RELEVANCE

Oral administration of COWP was determined to be a safe and effective method of reducing GIN FEC in adult alpacas.

Response of Rambouillet Lambs to an Artificial Gastrointestinal Nematode Infection

Gastrointestinal nematodes (GIN) threaten the productivity and health of sheep worldwide, prompting the need for genetic selection to reduce GIN susceptibility. Fecal egg count (FEC), packed-cell volume (PCV), and various production traits were examined in parasitized Rambouillet sheep and compared to sire FEC estimated breeding value (EBV). Rambouillet lambs (n = 77) were inoculated with 10,000 H. contortus L3 larvae. Subsequently, FEC, PCV, and body weight (BW) were captured at seven-day intervals for six weeks. Lambs were sired by one of two rams with post-weaning FEC EBV of −9% or +9%. Mean FEC differed (p = 0.0132) with lambs from the lower EBV sire (“Sire L”) being reduced, versus those from the higher EBV sire (“Sire H”), being 2135 ± 211 vs. 2912 ± 207 eggs per gram, respectively. Males and females did not differ for FEC, but females exhibited a higher mean PCV than males, (33.74 vs. 29.65%, p < 0.0001). Lambs were shorn ~120 d post artificial infection and wool measurements were captured. A negative correlation between FEC and grease fleece weight was observed. Our results describe the response of Rambouillet lambs to artificial H. contortus infection and suggest FEC EBV can reduce susceptibility to GIN in this breed.

Extensive Sheep and Goat Production: The Role of Novel Technologies towards Sustainability and Animal Welfare

Simple Summary

New technologies have been recognized as valuable in controlling, monitoring, and managing farm animal activities. It makes it possible to deepen the knowledge of animal behavior and improve animal welfare and health, which has positive implications for the sustainability of animal production. In recent years, successful technological developments have been applied in intensive farming systems; however, due to challenging conditions that extensive pasture-based systems show, technology has been more limited. Nevertheless, awareness of the available technological solutions for extensive conditions can increase the implementation of their adoption among farmers and researchers. In this context, this review addresses the role of different technologies applied to sheep and goat production in extensive systems. Examples related to precision livestock farming, omics, thermal stress, colostrum intake, passive immunity, and newborn survival are presented; biomarkers of metabolic diseases and parasite resistance breeding are discussed.

Abstract

Sheep and goat extensive production systems are very important in the context of global food security and the use of rangelands that have no alternative agricultural use. In such systems, there are enormous challenges to address. These include, for instance, classical production issues, such as nutrition or reproduction, as well as carbon-efficient systems within the climate-change context. An adequate response to these issues is determinant to economic and environmental sustainability. The answers to such problems need to combine efficiently not only the classical production aspects, but also the increasingly important health, welfare, and environmental aspects in an integrated fashion. The purpose of the study was to review the application of technological developments, in addition to remote-sensing in tandem with other state-of-the-art techniques that could be used within the framework of extensive production systems of sheep and goats and their impact on nutrition, production, and ultimately, the welfare of these species. In addition to precision livestock farming (PLF), these include other relevant technologies, namely omics and other areas of relevance in small-ruminant extensive production: heat stress, colostrum intake, passive immunity, newborn survival, biomarkers of metabolic disease diagnosis, and parasite resistance breeding. This work shows the substantial, dynamic nature of the scientific community to contribute to solutions that make extensive production systems of sheep and goats more sustainable, efficient, and aligned with current concerns with the environment and welfare.

An Artemisia cina n-hexane extract reduces the Haemonchus contortus and Teladorsagia circumcincta fecal egg count in naturally infected periparturient goats

The objective of this study was to evaluate an n-hexane extract of Artemisia cina (Acn-h) as a natural anthelmintic treatment for periparturient goats naturally infected with the nematodes Haemonchus contortus and Teladorsagia circumcincta. A total of 200 periparturient Alpine and Nubian goats were used. Deworming criteria were based on the following parameters: fecal egg account (epg), ocular mucosa color (OMC), and body condition (BC). A previous analysis using coprocultures of the flock revealed the presence of H. contortus (80%) and T. circumcincta (20%). The Acn-h contained two new compounds identified by mass spectrometry data as isoguaiacin and norisoguaiacin at 284.14 and 315 m/z. The lethal effects of Acn-h at 0.5, 1, 2, and 4 mg/mL on H. contortus adult stages were 31.6, 66.5, 81.3, and 86.9%, respectively (p < 0.05), showing similar efficacy at 2 and 4 mg/mL with albendazole (positive control group). Then, two experimental groups, with 100 goats in peripartum in each, were distributed randomly and treated at day 0 as follows: group 1 = 4 mg/kg of Acn-h as single oral dose, and group 2 = control group, treated with water (as a placebo). The epg, OMC, and BC parameters were recorded at 0 (periparturient period), 7 (birth period), and 23 (postpartum) days and analyzed using a completely randomized design with Duncan's test for comparison of means and analysis of variance. The following epg reductions were recorded in the Acn-h-treated group as follows: 20.1 ± 34.4 and 31.7 ± 38.2% at days 7 and 23 compared to the control group. During the whole experiment, no significant differences in OMC or BC were observed in relation to the control group, excepting at day 23 (p < 0.05) for BC in the group treated with A. cina. Thus, Acn-h can be a useful natural alternative tool for the control of the nematodes H. contortus and T. circumcincta in periparturient goat flocks.

The effect of pumpkin seed cake and ground cloves (Syzygium aromaticum) supplementation on gastrointestinal nematode egg shedding in sheep

The aim of this study was to evaluate the effect of feed additives (pumpkin seed cake and cloves) on the egg excretion of gastrointestinal nematodes (GIN) in sheep. Thirty ewes naturally infected with GIN were randomly selected from a flock and assigned to the following groups of 10 animals each: clove group (received 1.8 g ground cloves/ewe/day, for 7 days), pumpkin seed cake group (200 g pumpkin seed cake/ewe/day, for 7 days) and control group. Before starting the study, on day 0, and 5 days after the 7-day supplementation, on day 12, the body condition and FAMACHA scores were assessed and individual faecal egg counts (FEC) were performed. The mean body condition and the FAMACHA scores did not change significantly between day 0 and 12 with the exception of a significantly deteriorated FAMACHA score in the clove group. The percentage reduction of FEC was 40.7% on day 12 in the clove group and 52.9% in the pumpkin seed cake group. In the control group, FEC increased by 8.7%. A coproculture of faecal samples from four of the most infected animals on day 0 revealed Trichostrongylus spp. larvae L3 in all four selected ewes, Ostertagia spp. and Cooperia spp. in three and Haemonchus contortus in one ewe. These results are promising and encourage further studies aimed to evaluate the possibility that these plant supplements could be a complementary method for parasite control, thus reducing the need for chemotherapy.

A journey through 50 years of research relevant to the control of gastrointestinal nematodes in ruminant livestock and thoughts on future directions

This review article provides an historical perspective on some of the major research advances of relevance to ruminant livestock gastrointestinal nematode control over the last 50 years. Over this period, gastrointestinal nematode control has been dominated by the use of broad-spectrum anthelmintic drugs. Whilst this has provided unprecedented levels of successful control for many years, this approach has been gradually breaking down for more than two decades and is increasingly unsustainable which is due, at least in part, to the emergence of anthelmintic drug resistance and a number of other factors discussed in this article. We first cover the remarkable success story of the discovery and development of broad-spectrum anthelmintic drugs, the changing face of anthelmintic drug discovery research and the emergence of anthelmintic resistance. This is followed by a review of some of the major advances in the increasingly important area of non-pharmaceutical gastrointestinal nematode control including immunology and vaccine development, epidemiological modelling and some of the alternative control strategies such as breeding for host resistance, refugia-based methods and biological control. The last 50 years have witnessed remarkable innovation and success in research aiming to improve ruminant livestock gastrointestinal nematode control, particularly given the relatively small size of the research community and limited funding. In spite of this, the growing global demand for livestock products, together with the need to maximise production efficiencies, reduce environmental impacts and safeguard animal welfare - as well as specific challenges such as anthelmintic drug resistance and climate change- mean that gastrointestinal nematode researchers will need to be as innovative in the next 50 years as in the last.

The small-secreted cysteine-rich protein CyrA is a virulence factor participating in the attack of Caenorhabditis elegans by Duddingtonia flagrans

Nematode-trapping fungi (NTF) are a diverse and intriguing group of fungi that live saprotrophically but can switch to a predatory lifestyle when starving and in the presence of nematodes. NTF like Arthrobotrys oligospora or Duddingtonia flagrans produce adhesive trapping networks to catch and immobilize nematodes. After penetration of the cuticle, hyphae grow and develop inside the worm and secrete large amounts of hydrolytic enzymes for digestion. In many microbial pathogenic interactions small-secreted proteins (SSPs) are used to manipulate the host. The genome of D. flagrans encodes more than 100 of such putative SSPs one of which is the cysteine-rich protein CyrA. We have chosen this gene for further analysis because it is only found in NTF and appeared to be upregulated during the interaction. We show that the cyrA gene was transcriptionally induced in trap cells, and the protein accumulated at the inner rim of the hyphal ring before Caenorhabditis elegans capture. After worm penetration, the protein appeared at the fungal infection bulb, where it is likely to be secreted with the help of the exocyst complex. A cyrA-deletion strain was less virulent, and the time from worm capture to paralysis was extended. Heterologous expression of CyrA in C. elegans reduced its lifespan. CyrA accumulated in C. elegans in coelomocytes where the protein possibly is inactivated. This is the first example that SSPs may be important in predatory microbial interactions.

Control of Strongyles in First-Season Grazing Ewe Lambs by Integrating Deworming and Thrice-Weekly Administration of Parasiticidal Fungal Spores

Parasiticidal fungi have been used in several in vivo experiments in livestock farms worldwide, constituting an effective tool for the biocontrol of gastrointestinal parasites in grazing animals. In the first year of study, two groups of eight first-season pasturing ewe lambs infected by strongyles were dewormed with albendazole, and then, the test group received an oral dose of 10⁶ chlamydospores of Mucor circinelloides and 10⁶ Duddingtonia flagrans individually and thrice a week from mid-September to May (FS1), while the control group remained without fungi (CT1). In the second year, two new groups of first-season grazing ewe lambs were treated with ivermectin and subjected to the same experimental design (FS2 and CT2, respectively). The anthelmintic efficacy was 96.6% (CT1), 95.6% (FS1), 96.1% (CT2), and 95.1% (FS2). The counts of strongyle egg output increased in the control groups (CT1 and CT2) throughout the study and reached numbers higher than 600 eggs per gram of feces (EPG), while in FS1 and FS2, they were <250 EPG. The values of red blood cell parameters registered for CT1 and CT2 were lower than those of the reference standards, while a significant increment was recorded in FS1 and FS2, and values within the physiological range were attained. It is concluded that integrating efficient anthelminthic deworming with rotational pasturing and the regular intake of chlamydospores of M. circinelloides and D. flagrans provides a helpful strategy for maintaining low levels of strongyle egg output in first-season grazing ewe lambs and improves their health status.

Anthelmintic resistance: is a solution possible?

More than 50 years after anthelmintic resistance was first identified, its prevalence and impact on the animal production industry continues to increase across the world. The term "anthelmintic resistance" (AR) can be briefly defined as the reduction in efficacy of a certain dose of anthelmintic drugs (AH) in eliminating the presence of a parasite population that was previously susceptible. The main aim of this study is to examine anthelmintic resistance in domestic herbivores. There are numerous factors playing a role in the development of AR, but the most important is livestock management. The price of AH and the need to treat a high number of animals mean that farmers face significant costs in this regard, yet, since 1981, little progress has been made in the discovery of new molecules and the time and cost required to bring a new AH to market has increased dramatically in recent decades. Furthermore, resistance has also emerged for new AH, such as monepantel or derquantel. Consequently, ruminant parasitism cannot be controlled solely by using synthetic chemicals. A change in approach is needed, using a range of preventive measures in order to achieve a sustainable control programme. The use of nematophagous fungi or of plant extracts rich in compounds with anthelmintic properties, such as terpenes, condensed tannins, or flavonoids, represent potential alternatives. Nevertheless, although new approaches are showing promising results, there is still much to do. More research focused on the control of AR is needed.

Reproductive Management of Rams and Ram Lambs during the Pre-Breeding Season in US Sheep Farms

In sheep farms, achieving economic and productive efficiency and sustainability goals is directly related with the reproductive management of the animals. Genetically, the male contribution to the offspring is 50%, but in practical terms, there is a greater potential impact of the ram on reproductive results, because one male has the potential to affect a large group of females and therefore greatly affects the entire flock. Unfortunately, the selection of males for breeding in the US sheep industry has been traditionally conducted based on phenotypical traits, without a genetic/reproductive evaluation, and/or health assessment or records. Therefore, it is important to establish integrative management practices to select the rams and ram lambs to be used in the breeding season. Among these practices are genomic testing, a comprehensive breeding soundness evaluation and assessment of health status and records of the males before the breeding season, to detect and correct potential issues.

Effect of Artemisia absinthium and Malva sylvestris on Antioxidant Parameters and Abomasal Histopathology in Lambs Experimentally Infected with Haemonchus contortus

This study evaluated the effect of Artemisia absinthium and Malva sylvestris on antioxidant response and histopathological changes in the abomasa of the Haemonchus contortus infected lambs. Twenty-four lambs were divided into four groups: unsupplemented lambs (UNS), lambs supplemented with A. absinthium (ART), lambs supplemented with M. sylvestris (MAL), and lambs supplemented with both plants (ARTMAL). Lambs were infected orally with approximately 5000 third-stage (L3) larvae of H. contortus. The experiment was conducted for 75 d (days), all animals were then slaughtered; and the abomasal tissues were examined for antioxidant parameters and histopathology. The concentration of malondialdehyde in the abomasal mucosa was lower in ARTMAL (p < 0.05), and the total antioxidant capacity was higher in MAL (p < 0.05), than in UNS. Increased mucus production was observed in the ARTMAL. The number of mast cells in UNS and ART was significantly higher than the number in MAL (p < 0.01 and p < 0.05). Plasma cell numbers were higher in ARTMAL than the number in MAL (p < 0.05). Abomasal tissue regenerated more frequently in ARTMAL. These results represent the first report of the impact of A. absinthium and M. sylvestris on antioxidant parameters and local immune responses of abomasal mucosa of lambs infected with a GIN parasite.

Anthelmintic resistance and prevalence of gastrointestinal nematodes infecting sheep in Limpopo Province, South Africa

Background and Aim:

Previous studies recorded the prevalence of gastrointestinal nematodes (GIN) in Limpopo Province. However, the studies did not address the seasonal patterns of infection and did not cover all districts of Limpopo Province, namely; Capricorn, Sekhukhune, Waterberg, Mopani, and Vhembe. It is, therefore, important to provide up to date information on the prevalence and seasonal occurrence data of GIN in all districts of Limpopo province. The present study was conducted to determine the occurrence of anthelmintic resistance (AR) and document the prevalence of GIN infecting sheep in five districts of Limpopo Province, South Africa.

Materials and Methods:

Forty animals in each district were used for fecal egg count reduction test (FECRT) to determine AR against ivermectin (0.2 mg/kg), levamisole (LEV) (5 mg/kg), and albendazole (7.5 mg/kg). Egg hatch test (EHT) was used to determine AR against thiabendazole (TBZ) and micro-agar larval development test (MALDT) was used for both TBZ and LEV. Naturally, infected sheep (n=780) were sampled for prevalence across five districts of Limpopo. FAMACHA^© eye-color score estimations were also performed for each study animal.

Results:

FECRT showed occurrence of AR in most of the districts and a few with suspected resistance. EHT results showed AR development against TBZ for all districts, while the MALDT showed no AR against LEV in all districts, but detected AR against TBZ in Sekhukhune, Capricorn, and Waterberg. Haemonchus contortus was the most resistant species. A high nematode prevalence (88-100%) and 1210-1861 eggs per gram (EPG) was observed in all districts during the hot wet season, decreasing to 75-80% (453-1202 EPG) during the cold dry season. The sheep revealed a FAMACHA^© mean score of 3, indicating mild anemia during the hot wet season except for Vhembe district that revealed a FAMACHA^© mean score of 4 during the hot wet season, indicating anemia.

Conclusion:

AR recorded in Limpopo Province may be due to under-dosing caused by lack of weighing equipment and high treatment frequencies due to lack of proper training on anthelmintic use. The detection of AR in Limpopo is an important finding because it will help in outlining effective management systems against GIN.

Purpureocillium lilacinum and Trichoderma virens for biological control of trichostrongylid parasites of sheep: an in vitro evaluation

The study evaluated the ovicidal activity of enzymatic extracts of Purpureocillium lilacinum and Trichoderma virens against trichostrongylid eggs from sheep. Filtered extract (FE) and macerated crude extract (MCE) were prepared from fungal cultures in minimal broth. In the experiment, 100 trichostrongylid eggs, obtained from the feces of naturally infected sheep, were exposed to fungal extracts for 24 and 48 hours/25°C. In the control group, eggs were incubated in minimal broth. The number of L1 larvae was ascertained. Each treatment consisted of four repetitions and the experiment was repeated five times. It was observed that the effect of FE and MCE of P. lilacinum and T. virens on egg hatchability differed from that of the control group. MCE of T. virens and P. lilacinum showed higher ovicidal activity than FE over both periods and at 48 hours of exposure, respectively. From the percentage reductions in hatchability of the eggs, MCE was shown to be superior to FE for both fungi. This study demonstrated the ovicidal potential of these fungi against trichostrongylid eggs. However, further studies are needed in order to identify the molecules responsible for the ovicidal effects, and to evaluate the behavior of fungal extracts in biotic and abiotic interactions.

The effect of Brachiaria brizantha cultivars on host-parasite-environment interactions in sheep naturally infected with gastrointestinal nematodes

The objective was to evaluate the effect of different cultivars of Brachiaria brizantha on the dynamics and concentration of the larval stages of gastrointestinal nematodes in the soil and forage strata, as well as their effects on the performance of naturally infected lambs. Overall, 48 90-day-old lambs with an initial weight of 19.04 ± 0.96 kg were observed. Moreover, a randomised block factorial design with four cultivars of Brachiaria brizantha (Marandu, Xaraés, Piatã and Paiaguás grasses) under intermittent stocking (with a pre-grazing canopy height of 40 cm and post-grazing canopy height of 20 cm) for two grazing cycles was used. The following variables were analysed: faecal egg counting, faecal culture, mean corpuscular volume, FAMACHA^© score, weight and body condition score, the recovery of larvae from pasture and soil samples, nutritional value and the production and structural components of forage. Lambs grazing Marandu grass demonstrated the highest level of nematode infection (P < 0.05). However, the nutritional value did not differ between cultivars. Marandu grass had the highest pasture density (P < 0.05), while Paiaguás grass had the highest percentage of dead material (P < 0.05). The various genera of gastrointestinal nematodes found in the faecal cultures, regardless of the cultivars, include Haemonchus (92.01%), Trichostrongylus (4.55%), Strongyloides (3.06%) and Oesophagostomum (0.37%). Lambs grazing Xaraés grass had the lowest body weight (P < 0.05). Furthermore, larvae concentrations were highest in Marandu and Paiaguás pastures; infective Haemonchus and Trichostrongylus larvae were recovered from pasture and soil samples. The different cultivars of Brachiaria brizantha produce diverse and relevant microclimatic conditions to contaminate soil, pastures and animals. Animal performance was not compromised despite the Marandu and Paiaguás cultivars having the highest levels of contamination and infection. Based on parasitological aspects, the Brachiaria brizantha cultivars Xaraés and Piatã are recommended for grass-based sheep production systems over the other cultivars since they contribute to the reduction of larval contamination and infection.

What Modeling Parasites, Transmission, and Resistance Can Teach Us

Veterinarians and farmers must contend with the development of drug resistance and climate variability, which threaten the sustainability of current parasite control practices. Field trials evaluating competing strategies for controlling parasites while simultaneously slowing the development of resistance are time consuming and expensive. In contrast, modelling studies can rapidly explore a wide range of scenarios and have generated an array of decision support tools for veterinarians and farmers such as real-time weather-dependent infection risk alerts. Models have also been valuable for predicting the development of anthelmintic resistance, evaluating the sustainability of current parasite control practices and promoting the responsible use of novel anthelmintics.