Gastrointestinal Nematodes Of Cattle Research Articles

Environmental Factors Influence the Infestation of Gastrointestinal Nematodes in Cattle in Aceh Province

Environmental Factors Influence the Infestation of Gastrointestinal Nematodes in Cattle in Aceh Province

Ecology of the free-living stages of cattle nematodes in the dry season in the Lerma Valley, Salta province, Argentina

The objective of this work was to describe the dynamics of development and survival of the free-living stages of cattle gastrointestinal nematodes (GIN) in fecal matter (FM) and pasture during the dry season in the Lerma Valley, Salta province, northwestern Argentina (NWA) to contribute to GIN management. The climate in the region is characterized by a rainy summer followed by a dry season from middle autumn to early spring. Fecal matter from calves naturally infected with GIN was deposited on three experimental field plots in April, July and October 2019, corresponding to the beginning, middle and end of the dry season, respectively. Each experimental unit consisted of 7 stools of about 800 g and had four repetitions. To determine the development from egg to infective larvae (L3), the first sampling (5 g fecal matter) was performed from the 10th day post-contamination and continued every 3 days until L3 were found. Subsequently, a monthly sampling was made until two consecutive negative results were obtained. Sampling of pasture began three days after the L3 recovery from FM, and continued monthly until two negative results were obtained. The following parameters were evaluated: development time and development rate from egg to L3; permanence time of L3 in feces; time of appearance on pasture; migration rate; and permanence time of L3 on pasture. The main genera of parasites present were Cooperia and Haemonchus. Significant differences were observed in the development time among contamination months (p < 0.001); development time was highest in the July contamination (28 days), with October and April contamination averaging 9 and 10 days, respectively. Development time also showed significant differences (p < 0.01) among contamination months, being highest in October (31.48%). The highest permanence time in fecal matter values were recorded in the July contamination (183 days) and migration rate was highest in the October contamination (42.49%). The highest time of appearance on pasture value was recorded in the July contamination (117 days). Finally, the highest permanence time of L3 in feces values were detected in the October contamination (148 days). The results of this work show that fecal contamination in the NWA region in the dry season would play an epidemiological role in the GIN cycle as a source of infection for the next productive cycle in the rainy season.

Dose confirmation of a novel fixed dose combination injectable (0.2 mg/kg doramectin + 6.0 mg/kg levamisole hydrochloride) against naturally acquired gastrointestinal nematodes in US cattle

Macrocyclic lactone (ML) resistance in cattle gastrointestinal nematodes (GINs) is an increasing problem. Concurrent combination anthelmintic therapy incorporating an existing ML with a second drug class has been proposed to control cattle GINs while slowing the development of ML resistance. Two dose confirmation studies were conducted to investigate the efficacy of a new fixed-dose combination injectable (FDCI) anthelmintic against common cattle GINs known to negatively impact production. The FDCI is formulated with 5 mg/ml doramectin and 150 mg/ml levamisole hydrochloride (HCl). Cattle enrolled in the two studies were sourced from either the Southern (Study 1, n = 30) or Midwest (Study 2, n = 36) United States. Animals with GIN infections confirmed by fecal egg count (FEC) were randomly allocated to one of three treatment groups. On Day 0, cattle with positive FECs on Day −5( ± 2) were weighed and administered a single subcutaneous injection of either saline (0.9% sodium chloride) at 0.04 ml/kg, 10 mg/ml doramectin at 0.02 ml/kg (to provide 0.2 mg/kg doramectin) or the FDCI at 0.04 ml/kg (to provide 0.2 mg/kg doramectin and 6.0 mg/kg levamisole HCl). On Day 14, fecal samples were collected, animals were euthanized, and worms were collected from the intestinal tract of each animal. Treatment efficacy was calculated using worm burdens and the fecal egg count reduction test (FECRT). Pre-treatment (Day −5, Study 1; Day −3, Study 2) mean FECs were 999.4–1136.2 eggs per gram (EPG) in Study 1 and 137.1–226.6 EPG in Study 2. The FDCI was active against cattle GIN populations in both studies, with FECRT ≥ 99.98% in both studies. Compared to saline-treated cattle, FDCI-treated cattle had significantly fewer adult and immature worms of all identified species on Day 14. In Study 1, Day 14 efficacy of the FDCI was 96.9% for Cooperia spp. (C. oncophora (99.7%) and C. punctata (95.9%)), 99.1% for Nematodirus helvetianus, and 99.8% for Ostertagia spp. In Study 2, the FDCI provided 100% efficacy against all adult GIN species identified, including all GINs identified in Study 1 and Trichostrongylus axei. The FDCI also provided 95.5% efficacy against immature Ostertagia spp. and 100% efficacy against immature Cooperia spp. (Study 2). Doramectin was effective against all adult cattle GINs (except N. helvetianus) in Study 2 but was only effective against adult Ostertagia spp. in Study 1. Additionally, doramectin was only effective against immature Cooperia spp. (and not immature Ostertagia spp.) in Study 2. A single administration of the doramectin + levamisole HCl FDCI provides a new and effective approach to the treatment and control of common cattle GINs, including those exhibiting decreased susceptibility to doramectin alone.

Efficacy of a fixed-dose combination injectable (0.2 mg/kg doramectin + 6.0 mg/kg levamisole hydrochloride) in Australian cattle against naturally acquired gastrointestinal nematode infections

Australian producers have long used macrocyclic lactones (MLs) to successfully control cattle gastrointestinal nematodes (GINs) and consequently improve production parameters. However, the trajectory of ML resistance development in cattle GINs is following that of small ruminant nematode populations, highlighting a need for novel treatment options to provide efficacy in the current environment and interrupt the long-term establishment of ML-resistant GIN populations in Australian cattle. Here, we describe three field studies conducted in Australia to evaluate the efficacy of a single administration of a novel fixed-dose combination injectable (FDCI) endectocide against naturally acquired infections of cattle GINs. The FDCI is administered subcutaneously to deliver 0.2 mg/kg doramectin and 6 mg/kg levamisole hydrochloride (HCl). Study sites consisted of three farms in New South Wales (n = 2) and Victoria (n = 1). At each site, cattle were randomly allocated into one of three treatment groups: (1) untreated control (saline), (2) FDCI (0.2 mg/kg doramectin, 6 mg/kg levamisole HCl) or (3) positive control (0.2 mg/kg ivermectin). All treatments were administered on Day 0. Fecal samples were collected prior to treatment on Days −1 (Study 3) or 0 (Studies 1 and 2) and again on Day 14 (post-treatment) to evaluate efficacy via fecal egg count (FEC) and for coproculture. Adequacy of infection was confirmed at all three study sites, with Day 14 geometric mean (GM) FECs for saline-treated cattle ranging from 32.5 eggs per gram (EPG) to 623.7 EPG. FECs for FDCI-treated cattle were significantly reduced compared to saline-treated cattle (p ≤ 0.0001) on Day 14, with GM-based efficacy ≥ 99.7% at all three study sites. In contrast, ivermectin was 97.4% effective against cattle GINs in Study 1 but was only 47.2% and 39.8% effective at study site 2 and 3, respectively. Genus-specific efficacies suggest the presence of ivermectin-resistant Cooperia spp. (Study 1), Haemonchus spp. (Study 2) and Ostertagia spp. (Study 3) populations in the naturally infected cattle used in these studies. The post-treatment FEC and genus-specific efficacy estimations indicate the doramectin + levamisole HCl FDCI was highly efficacious against cattle GINs even in the face of ivermectin LOE at study sites 2 and 3. The efficacy of the new FDCI against both ML-susceptible and ML-resistant economically important cattle GINs in Australia affirms it is a valuable treatment option for producers operating in an environment of ML loss of efficacy.

Efficacy of a fixed-dose combination injectable (0.2 mg/kg doramectin + 6.0 mg/kg levamisole hydrochloride) in New Zealand cattle against naturally acquired gastrointestinal nematode populations with demonstrated resistance to doramectin

Intensive farming practices and heavy reliance on anthelmintics have contributed significantly to the problem of macrocyclic lactone (ML) resistance in New Zealand. Farmers now have few options for effectively controlling cattle gastrointestinal nematodes (GINs) and regularly experience sub-optimal efficacy against economically important species. We present a novel fixed-dose combination injectable (FDCI) that simultaneously delivers 0.2 mg/kg doramectin and 6 mg/kg levamisole hydrochloride (HCl) to target a broad spectrum of cattle GINs in a single dose, providing an additional solution to endoparasite control in an environment of anthelmintic resistance. A dose confirmation study was conducted using naturally acquired infections of GINs in beef cattle in New Zealand. Cattle with GIN infections confirmed by fecal egg count (FEC) were randomly allocated (n = 12 per group) to the control (saline-treated), FDCI-treated or doramectin-treated group. On Day 0, cattle were weighed and administered a single subcutaneous injection of saline or endectocide. Rectal fecal samples were collected from each animal on Day 7 for individual duplicate fecal egg count (FEC) analysis, and coprocultures were conducted on pooled fecal samples within each treatment group. All animals were euthanized and necropsied for worm recovery on Days 14 through 16. Treatment efficacy was calculated based on reduction in FECs and worm burdens. All enrolled cattle were positive for GINs based on Day −5 FECs, with geometric mean (GM) FECs ranging from 337 to 521 eggs per gram (EPG). All saline-treated cattle remained positive for GIN infections for the study duration (Day 7 GM FEC = 427 EPG). Necropsy and worm recoveries revealed the presence of doramectin-resistant Cooperia oncophora, C. surnabada and Trichostrongylus longispicularis, as evidenced by ≤ 72.3 % efficacy of doramectin against these species. The new FDCI was ≥ 99.8 % effective against all GIN species, including ML-resistant C. oncophora, C. surnabada and T. longispicularis, providing broad-spectrum efficacy and eliminating economically important cattle GINs, including ML-resistant populations.

Trapping Behaviour of Duddingtonia flagrans against Gastrointestinal Nematodes of Cattle under Year-Round Grazing Conditions.

The purpose of using nematophagous fungi as biological control agents of gastrointestinal nematodes of livestock is to reduce the build-up of infective larvae on pasture and thus avoid clinical and subclinical disease. As the interaction of fungus-larval stages takes place in the environment, it is crucial to know how useful the fungal agents are throughout the seasons in areas where livestock graze all year-round. This study was designed to determine the predatory ability of the nematophagous fungus Duddingtonia flagrans against gastrointestinal nematodes of cattle during four experiments set up in different seasons. In each experiment, faeces containing eggs of gastrointestinal nematodes were mixed with 11,000 chlamydospores/g and deposited on pasture plots. A comparison between fungal-added faeces and control faeces without fungus were made with regard to pasture infectivity, larval presence in faecal pats, faecal cultures, faecal pat weight, and temperature inside the faecal mass. In three of the four experiments, Duddingtonia flagrans significantly reduced the population of infective larvae in cultures (68 to 97%), on herbage (80 to 100%), and inside the faecal pats (70 to 95%). The study demonstrated the possibility of counting on a biological control tool throughout most of the year in cattle regions with extensive grazing seasons.

Homeopathic treatments efficacy against gastrointestinal nematodes in cattle from the Ecuadorian low tropics

Con el objetivo de evaluar la eficacia de tratamientos homeopáticos en el control de nematodosis gastrointestinal en bovinos, a través del porcentaje de reducción (%RH) de huevos por gramo de heces (HPG), se realizó una investigación con 60 bovinos mestizos, los cuales se ajustaron según su edad y distribuyeron en cinco tratamientos (T), tres con remedios homeopáticos (Arsenicum album, Artemisia cina y Sulphur), un grupo alopático (Fenbendazol 10 %) y otro control, siendo administrados por vía oral, a una dosis de 10 mL·animal-1·día-1, en los T homeopáticos al grupo respectivo, y al control agua destilada por cinco días consecutivos; al T alopático se le suministró una única dosis de 5 mg·kg-1 de peso vivo. La eficacia fue calculada a través del %RH, comparado con el grupo control. Los resultados obtenidos mostraron que el T alopático, obtuvo un %RH de 88,5 % en la cuarta semana, pero con disminución del %RH desde la séptima a la novena semana con 42,68 y 5,32 %, respectivamente. En el caso de los remedios homeopáticos, el que presentó mejor eficacia fue A. cina con una reducción del 93,62 % en la novena semana del estudio; en el caso de sulphur 84,57 % y A. album, mostró un %RH hasta 49,96 %. Remedios homeopáticos como A. cina y sulphur mostraron eficacia frente a nematodos gastrointestinales en bovinos, siendo unas alternativas a productos alopáticos como Fenbendazol 10 %, por su mayor %RH a través del ensayo.

Diagnóstico de parasitosis gastrointestinal en ganado vacuno de razas carniceras con diferentes técnicas coproparasitológicas

Gastrointestinal parasites in production cattle are one of the most important health problems worldwide. These nematodes cause gastroenteric problems that are clinically characterized by diarrhoea, weakness, bleeding and dehydration. Within the gastrointestinal parasites caused by nematodes in cattle, the following families stand out: Trichuridae, Trichostrongylidae, Ancylostomidae, Ascaridae and Strongyloididae. The purpose of this research was to determine the efficacy of the different qualitative and quantitative coproparasitological techniques for the detection of gastrointestinal nematodes in cattle. For this study, 250 samples of beef breed cows were used, divided into different groups, for the application of qualitative and quantitative coproparasitological techniques, which were specifically chosen taking into account inclusion and exclusion criteria for each animal. The results delivered by this study indicated that the highest percentage in the identification of parasitic infective states was through qualitative coproparasitological techniques, focused mainly on zinc and magnesium sulfate flotation techniques with 50%.

An improved model for the population dynamics of cattle gastrointestinal nematodes on pasture: parameterisation and field validation for Ostertagia ostertagi and Cooperia oncophora in northern temperate zones

Gastrointestinal nematodes (GIN) are amongst the most important pathogens of grazing ruminants worldwide, resulting in negative impacts on cattle health and production. The dynamics of infection are driven in large part by the influence of climate and weather on free-living stages on pasture, and computer models have been developed to predict infective larval abundance and guide management strategies. Significant uncertainties around key model parameters limits effective application of these models to GIN in cattle, however, and these parameters are difficult to estimate in natural populations of mixed GIN species. In this paper, recent advances in molecular biology, specifically ITS-2 rDNA ‘nemabiome’ metabarcoding, are synthesised with a modern population dynamic model, GLOWORM-FL, to overcome this limitation. Experiments under controlled conditions were used to estimate rainfall constraints on migration of infective L3 larvae out of faeces, and their survival in faeces and soil across a temperature gradient, with nemabiome metabarcoding data permitting species-specific estimates for Ostertagia ostertagi and Cooperia oncophora in mixed natural populations. Results showed that L3 of both species survived well in faeces and soil between 0 and 30 °C, and required at least 5 mm of rainfall daily to migrate out of faeces, with the proportion migrating increasing with the amount of rainfall. These estimates were applied within the model using weather and grazing data and use to predict patterns of larval availability on pasture on three commercial beef farms in western Canada. The model performed well overall in predicting the observed seasonal patterns but some discrepancies were evident which should guide further iterative improvements in model development and field methods. The model was also applied to illustrate its use in exploring differences in predicted seasonal transmission patterns in different regions. Such predictive modelling can help inform evidence-based parasite control strategies which are increasingly needed due climate change and drug resistance. The work presented here also illustrates the added value of combining molecular biology and population dynamics to advance predictive understanding of parasite infections.

Comparative study of the effects of albendazole and annual mug wort (Artemisia annua) powder on gastrointestinal nematodes in cattle

Comparative study of the effects of albendazole and annual mug wort (Artemisia annua) powder on gastrointestinal nematodes in cattle

Efficacy of annual mugwort (Artemisia annua) powder on gastrointestinal nematodes in cattle

Parasitism remains a challenge in the effective and efficient management of ruminant livestock. Among the different approaches proposed for a better management of these different ruminant parasites, the present work carried out on the farm of the Faculty of Agronomic Sciences (FSA) located in Sékou, focused on the effectiveness of the annual mugwort powder (Artemisia annua) on gastrointestinal nematodes (Nematoda) of cattle. The coprological analyses were made at the Laboratory of Ethno pharmacology and Animal Health (LESA) in a population of eighteen (18) animals, divided in 2 groups with treatment and one without treatment. The result after treatment showed that the Artemisia annua powder significantly reduced the excretion of nematode eggs. It is noted that the more the animals are infested the faster there is a decrease in egg excretion.

Comparative study of the effects of albendazole and annual mug wort (Artemisia annua) powder on gastrointestinal nematodes in cattle

Nowadays, cattle breeding is a major economic issue throughout the world. However, gastrointestinal nematode parasitism remains a major sanitary threat on a global scale, affecting animal health, farm productivity and the well-being of farmers. Until recently, chemical anthelmintics occupied a prominent place in the fight against these parasites. But some of them have developed resistance to antiparasitic drugs. The objective of this study is to compare the anthelmintic effects of commercial albendazole (8.3 mg/kg body weight) and annual mugwort (Artemesia annua, 100 mg and 150 mg) powder on gastrointestinal roundworms in cattle. Lots of animals were formed in a population of 92 animals, and underwent different treatments: with albendazole and with annual mugwort powder. The results showed that the artemesia annua powder has a strong inhibition on the nematodes but failed to eliminate them completely. Albendazole, for its part, showed a very effective effect with a 100% elimination of nematodes. These results highlight the possibility of using annual mugwort as an alternative to albendazole on farms.

Efficacy of annual mugwort (Artemisia annua) powder on gastrointestinal nematodes in cattle

Efficacy of annual mugwort (Artemisia annua) powder on gastrointestinal nematodes in cattle

In vitro anthelmintic activity of Physalis minima ethanolic leaves and stem extracts against Paramphistomum cervi from cattle

BackgroundCrude ethanolic extracts of leaves and stem of Physalis minima (Solanaceae) were evaluated for in vitro anthelmintic activity on the Bangladeshi mature parasitic flatworm Paramphistomum cervi (Trematoda) in cattle. To compare the test results, Albendazole was used as a standard drug.MethodsA leaves and stem extract of the P. minima was prepared in a Soxhlet apparatus using ethanol as a solvent. After concentrating in a vacuum rotary evaporator, the extract was analyzed for phytochemical activities. In vitro anthelmintic activity was tested against the flat worm P. cervi.ResultsThe results of anthelmintic activity of P. minima were evaluated by paralysis instead of taking as of the paralysis time and death time of the flatworm. The study concluded that the ethanolic leaves and stem extracts of P. minima had anthelmintic activity in a dose-dependent inhibition of spontaneous motility of flatworm. From the screening experiment, the crude extracts showed the best anthelmintic activity. Furthermore, our phytochemical studies point out that ethanolic extract of the leaves and stem of P. minima contains flavonoids, phenols alkaloids, terpenoids, tannins, steroids, proteins and cardiac glycosides.ConclusionsThe studies of total phenolic and flavonoids content were quantified for all parts of the plant. The results of the present study suggest that P. minima extracts are a promising alternative to the commercially available anthelmintics for the treatment of gastrointestinal nematodes of cattle. Further research is required to confirm the possibility of the antimicrobial and antiproliferative applications.

Regional heterogeneity and unexpectedly high abundance of Cooperia punctata in beef cattle at a northern latitude revealed by ITS-2 rDNA nemabiome metabarcoding

BackgroundThe species composition of cattle gastrointestinal nematode (GIN) communities can vary greatly between regions. Despite this, there is remarkably little large-scale surveillance data for cattle GIN species which is due, at least in part, to a lack of scalable diagnostic tools. This lack of regional GIN species-level data represents a major knowledge gap for evidence-based parasite management and assessing the status and impact of factors such as climate change and anthelmintic drug resistance.MethodsThis paper presents a large-scale survey of GIN in beef herds across western Canada using ITS-2 rDNA nemabiome metabarcoding. Individual fecal samples were collected from 6 to 20 randomly selected heifers (n = 1665) from each of 85 herds between September 2016 and February 2017 and 10–25 first season calves (n = 824) from each of 42 herds between November 2016 and February 2017.ResultsGastrointestinal nematode communities in heifers and calves were similar in Alberta and Saskatchewan, with Ostertagia ostertagi and Cooperia oncophora being the predominant GIN species in all herds consistent with previous studies. However, in Manitoba, Cooperia punctata was the predominant species overall and the most abundant GIN species in calves from 4/8 beef herds.ConclusionsThis study revealed a marked regional heterogeneity of GIN species in grazing beef herds in western Canada. The predominance of C. punctata in Manitoba is unexpected, as although this parasite is often the predominant cattle GIN species in more southerly latitudes, it is generally only a minor component of cattle GIN communities in northern temperate regions. We hypothesize that the unexpected predominance of C. punctata at such a northerly latitude represents a range expansion, likely associated with changes in climate, anthelmintic use, management, and/or animal movement. Whatever the cause, these results are of practical concern since C. punctata is more pathogenic than C. oncophora, the Cooperia species that typically predominates in cooler temperate regions. Finally, this study illustrates the value of ITS-2 rDNA nemabiome metabarcoding as a surveillance tool for ruminant GIN parasites.Graphical

A simple molecular method to identify and quantify genera of gastrointestinal nematodes of cattle.

Classic approaches for antemortem identification of gastrointestinal nematodes (GIN) require coproculture of eggs and morphological examination. While adequate for diagnosis, many PCR techniques cannot easily quantify mixed infections without controls and/or standard curves. Herein, we developed a simple and rapid test for differentiating and quantifying mixed infections of GIN using PCR products separated by capillary electrophoresis. Among the cattle GIN, the ITS2 region is sufficiently distinct in length to delineate among the most common infecting genera, Ostertagia ostertagi = 373 bases (b), Haemonchus contortus (placei) = 366b, Cooperia punctata (oncophora) = 376b, Trichostrongylus axei = 372b, and Oesophagostomum radiatum = 357b. Conserved primers were synthesized that span the ITS2 where one primer was fluorescently labeled with 6-FAM. DNAs from infective L3 were PCR amplified then loaded onto an ABI 3130 sequencer adapted for size fragment analysis. Resulting peak amplitudes were both diagnostic and quantitative on a relative basis. As proof of principle, quantification was performed on PCR fragments from mixed species pairs of Ostertagia ostertagi, Cooperia punctata, and Haemonchus contortus and analyzed using Gene Marker V1.85 software. In all cases, linear responses were observed where R2 > 0.97 and line slopes ranged between 0.90 and 1.1. When tested on eggs from naturally infected animals, the assay showed superior results on two farms when compared to coproculture and morphological identification. Using wildlife-derived samples, results coincided well with deep amplicon sequencing. The assay is adaptable to large-scale studies, does not require comparative PCR controls, and should be compliant with GIN from small ruminant livestock.

Anthelmintic activity of pomegranate peel extract (Punica granatum) and synthetic anthelmintics against gastrointestinal nematodes in cattle, sheep, goats, and buffalos: in vivo study.

Parasitic gastroenteritis (PGE) is one of the most important parasitic diseases that causes economic losses and health problems in ruminants. PGE causes a drop in milk, meat, and wool production in addition to decreasing animal fertility and sometimes leading to animal death. Conventional anthelmintics used for animal treatment are expensive, especially for farmers in developing countries. Moreover, the concern of anthelmintic resistance to these synthetic drugs is rising. Therefore, this study aimed to evaluate the anthelmintic activity of plant extract pomegranate (Punica granatum L) peel extract (PPE) against PGE infestations among ruminants. A total of 120 ruminants of different species (20 cattle, 12 buffalos, 68 sheep, and 20 goats) were examined for PGE eggs in their fecal samples. The animals under experiment were divided into four groups: the first group (negative control) was not given any drugs, the second group was given ivermectin (0.5ml/25kg bwt) (positive control 1), the third group was given albendazole (2.5mg active principle/kg bwt) (positive control 2), and the fourth group was given PPE (200mg/kg bwt). Fecal egg count (FEC) was performed on day 0 prior to the 1st dose of treatment. On day 15, an additional treatment (with the same doses) was administered and FEC was performed on days 7 and 21. Our results showed that on the 7th day of the experiment, there was an increase in FEC in the negative control group by 5%, while in the second, third, and fourth groups, there was a decrease in FEC with 95%, 90%, and 85% respectively. On the 21st day (7days from the second dose), there was an increase in FEC in the control group by a 10% and 100% reduction in FEC in both the second and third groups. While in the fourth group, there was a decrease in FEC by 97%. In conclusion, PPE could be used as a safe, cheap, and effective natural anthelmintic against PGE.

Resistance of bovine gastrointestinal nematodes to four classes of anthelmintics in the semiarid region of Paraíba state, Brazil.

The effectiveness of four anthelmintic classes on cattle gastrointestinal nematodes in the semi-arid region of Paraiba State, Brazil, was evaluated. Twenty farms were used, testing 40 animals in each one, totaling 800 animals. Cattle were divided into four groups composed with ten animals: I, treated with albendazole sulfoxide 15%; II, treated with ivermectin 1%; III, treated with closantel 25%; IV, treated with levamisole hydrochloride 7.5%. All treatments were administered subcutaneously. For the Fecal Egg Count Reduction Test (FECRT), individual fecal samples were collected on days 0 and 14, and sent for analysis of egg count per gram of feces (EPG) and larval cultures. It was observed that multiresistance was present in 95% (19/20) of the farms. Resistance to ivermectin and albendazole was observed in 95% (19/20), to closantel in 75% (15/20) and to levamisole in 20% (4/20). The most used management system was semi-intensive (75%; 15/20) and the ivermectin was the most reported drug for controlling helminths (65%; 13/20). Haemonchus spp. was the most prevalent helminth genus. It was concluded that the anthelmintic resistance of bovine gastrointestinal nematodes is high in the semi-arid of Paraíba State, Brazil, with multiresistance observed mainly to ivermectin, albendazole and closantel.

Untangling conflicting messages

Anthelmintic resistance in gastrointestinal nematodes of cattle has been worsening over the past 2 decades and is now a global problem. Though the problem was originally seen primarily in Cooperia, which is not a highly pathogenic species, we now know that other more pathogenic species have become drug resistant as well. With no new classes of anthelmintics in the cattle product pipeline, we will need to be better stewards of the drugs we have now, as they will need to last us for a long time. Thus, there is a need to use our anthelmintics differently and smarter than in the past. In this paper we present several strategies for improving the sustainability of parasite control in cattle that will both reduce the development of resistance while maintaining good productivity. Furthermore, we should not just assume a drug works or does not work; testing using the fecal egg count reduction test (FECRT) should be performed on every farm. This is the only way to make evidence-based decisions on optimal drug choices. Optimally, the strategies promoted here should have been instituted years ago. However, it is not too late, and the sooner these strategies are implemented widely, the more successful the beef industry will be in controlling parasites both now and in the future.

High levels of third-stage larvae (L3) overwinter survival for multiple cattle gastrointestinal nematode species on western Canadian pastures as revealed by ITS2 rDNA metabarcoding

BackgroundThe ability of infective larvae of cattle gastrointestinal nematode (GIN) species to overwinter on pastures in northerly climatic zones with very cold dry winters is poorly understood. This is an important knowledge gap with critical implications for parasite risk assessment and control.MethodsInfective third-stage larvae (L3) were quantified in samples of fecal pats, together with adjacent grass and soil, before and after winter on three farms in southern, central and northern Alberta. Nemabiome ITS2 metabarcoding was then performed on the harvested L3 populations to determine the species composition. Finally, parasite-free tracer calves were used to investigate if the L3 surviving the winter could infect calves and develop to adult worms in spring.ResultsFarm level monitoring, using solar powered weather stations, revealed that ground temperatures were consistently higher, and less variable, than the air temperatures; minimum winter air and ground temperatures were − 32.5 °C and − 24.7 °C respectively. In spite of the extremely low minimum temperatures reached, L3 were recovered from fecal pats and grass before and after winter with only a 38% and 61% overall reduction over the winter, respectively. Nemabiome ITS2 metabarcoding assay revealed that the proportion of L3 surviving the winter was high for both Cooperia oncophora and Ostertagia ostertagi although survival of the former species was statistically significantly higher than the latter. Nematodirus helvetinaus and Trichostrongylus axei could be detected after winter whereas Haemonchus placei L3 could not overwinter at all. Adult C. oncophora, O. ostertagi and N. helvetianus could be recovered from tracer calves grazing after the winter.ConclusionsThe largest proportion of L3 were recovered from fecal pats suggesting this is important refuge for L3 survival. Results also show that L3 of several GIN parasite species can survive relatively efficiently on pastures even in the extreme winter conditions in western Canada. Tracer calf experiments confirmed that overwintered L3 of both C. oncophora and O. ostertagi were capable of establishing a patent infection in the following spring. These results have important implications for the epidemiology, risk of production impact and the design of effective control strategies. The work also illustrates the value of applying ITS2 nemabiome metabarcoding to environmental samples.