Nematodes In Cattle Research Articles

Effects of anthelmintic treatment on production performance, carcass quality, and predominant nematode species in feedlot cattle from western Canada

The objective of this study was to determine the effects of currently used anthelmintics on production performance, carcass quality characteristics, and species diversity in western Canadian feedlot calves. Changes in climate and anthelmintic susceptibility are changing the epidemiology of gastrointestinal nematodes in livestock. However, the production impact of gastrointestinal nematodes in beef cattle from western Canada has not been studied in decades.

Exploring the species diversity of gastrointestinal nematodes in western Canadian beef cattle

The objectives of this study were to explore herd level species diversity of gastrointestinal nematode (GIN) communities in calves from western Canada and the effects of anthelmintic treatment on their relative species abundance in feedlot steers. Coinfection with multiple GIN species is common in cattle. Exploring the GIN diversity is important to understand parasite epidemiology and particularly the response to control programs; however, research is limited in Canadian beef cattle.

Rhabditis spp., in the Espírito Santo, State of Brazil and evaluation of biological control.

The objectives of this study were to describe occurrences of Rhabditis spp. causing parasitic otitis in dairy cattle of Gir breed in the state of Espírito Santo, southeastern Brazil, and to evaluate the biological control of this nematode using the nematophagous fungi Duddingtonia flagrans (AC001) and Monacrosporium thaumasium (NF34). After nematode detection and collection, three groups were formed: two groups that were treated, respectively, with the fungal isolates; and a control group, without fungus. The treatments were as follows: (a) Petri dishes containing the culture medium 2% water agar (WA) + 250 nematodes + AC001; (b) Petri dishes containing 2% WA + 250 nematodes + NF34; and (c) Petri dishes containing only 2% WA + 250 nematodes. After seven days at 27 °C the treatments with fungi were able to capture and destroy the nematodes, with percentages of 82.0% (AC001) and 39.0% (NF34) in relation to the control group. The results demonstrate the occurrence of Rhabditis spp. after animals physical examination and that there was efficacy of the in vitro predatory activity of both fungal isolates. Thus, these results are important because they can assist in future in vivo control of this nematode in cattle.

Status of Anthelmintic Resistance of Fenbendazole against Gastrointestinal Nematodes in Cattle of Haryana

Status of Anthelmintic Resistance of Fenbendazole against Gastrointestinal Nematodes in Cattle of Haryana

Diagnostic Study of Nematodes in Cattle in Mosul city

The present study was arranged to investigate the existence of different species of Nematodes which infect the cattle thorough an examination of 484 faecal samples which were collected randomly from Mosul city and around regions of it, during the period from October 2011 to June 2012 and determination infection severity of them. The total percentage of infection with Nematodes was 23.34%. The significant variations in percentages of infection were recorded according to months of study. The highest percentage was in December 42.10% and the lowest in February at 2.63%. In this study were diagnosed 13 genera of Nematodes, most of them Haemonchus spp. and Ostertagia spp. In the estimation of infection severity with Nematodes, significant variations were showed among the light infection with both of moderate and severe infection and the highest percentage of light has accomplished to 67.25% and the lowest in moderate infection was 11.50%.

Farmer Behavior and Gastrointestinal Nematodes in Ruminant Livestock-Uptake of Sustainable Control Approaches.

Gastrointestinal nematode (GIN) infections are a common constraint in pasture-based herds and cause a decrease in animal health, productivity and farm profitability. Current control practices to prevent production losses of GIN infections in livestock depend largely on the use of anthelmintic drugs. However, due to the continued use of these drugs over more than three decades, the industry is now increasingly confronted with nematode populations resistant to the available anthelmintics. This emerging anthelmintic resistance (AR) in cattle nematodes emphasizes the need for a change toward more sustainable control approaches that limit, prevent or reverse the development of AR. The uptake of diagnostic methods for sustainable control could enable more informed treatment decisions and reduce excessive anthelmintic use. Different diagnostic and targeted or targeted selective anthelmintic control approaches that slow down the selection pressure for anthelmintic resistance have been developed and evaluated recently. Now it is time to transform these insights into guidelines for sustainable control and communicate them across the farmer community. This article reviews the current uptake of such sustainable practices with a focus on farmer's socio-psychological factors affecting this uptake. We investigate communication as a possible tool to change current behavior and successfully implement more sustainable anthelmintic treatment strategies.

Anthelmintic resistance in cattle: A systematic review and meta-analysis

A systematic review and meta-analysis was conducted to identify, evaluate, and synthesize primary literature reporting the efficacy of anthelmintic drugs in cattle. Information on the bibliographic data, anthelmintic drugs, animals, reduction method, days after application, parasite genera, type of application, and dosage were collected. The final data base was composed of 70 articles published between 1986 and 2016 with a total of 8,976 animals. The mode of application interfered with the efficacy of anthelmintic drugs in cattle (P < 0.05); oral application was superior to injectable and pour-on drugs. The combined use of drugs was superior to single macrocyclic lactones including ivermectin (P < 0.05), in this way the combined use was more effective than the single use of drugs for the control of gastro-intestinal nematodes in cattle (P < 0.05). Nematode genera in the abomasum (Ostertagia spp., Haemonchus spp.) and intestine (Cooperia spp.) were evaluated. Levamisole had a greater efficacy for Cooperia spp. than Ostertagia spp. (P < 0.05); ivermectin had a greater efficacy for Ostertagia spp. than Haemonchus spp. (P < 0.05); doramectin had a greater efficacy for Ostertagia spp. than Cooperia spp. (P < 0.05). Dosing in larger quantities and according to the manufacturer's recommendation was most efficient, and the dose limiting species differed between substance classes. The test based on the count of eggs per gram of faeces indicated a reduced efficacy of the drug as days passed following treatment. The forest plot did not show a difference (P > 0.05) between interventions (resistance and efficacy). The results of this systematic review and meta-analysis suggest that anthelmintic resistance in cattle is present on several continents. Therefore, there is a need to replace the schemes based on the exclusive use of drugs in order to decrease the selection pressure.

Reduction of bovine strongilides in naturally contaminated pastures in the southeast region of Brazil

Biological control through the use of nematophagous fungi is a sustainable alternative for combatting helminthes in domestic animals and allows a reduction in the use of anthelmintics. The objective of this research was to evaluate the efficacy of the Arthrobotrys cladodes var macroides fungus in a pelleted formulation, based on sodium alginate and administered twice a week orally, as an alternative for the biological control of nematodes in field-grown young cattle. The experiment was conducted in a farm located in the municipality of Viçosa, MG, where 12 cattle, seven to nine months old, were allocated in two groups (treated group and control group) and distributed in pickets of Brachiaria decumbens, naturally infested with nematode larvae. The animals in the treated group received 1g of sodium alginate matrix pellets for every 10 kg of animal live weight, containing the nematophagous fungus Arthrobotrys cladodes var macroides and administered twice a week in conjunction with commercial feed. In the control group, each animal received 1 g of pellets for every 10 kg of animal live weight, without fungal mycelium added to the feed. Samples of feces and pastures were collected fortnightly for 12 months. The results showed that the most prevalent nematode genera in the coprocultures were Haemonchus sp., Cooperia sp. and Oesophagostomum sp., reflecting the results found in forage. The pasture that contained the animals that received feed with the fungus presented a reduction of 59% and 52% of larvae recovered at distances of 20 cm and 40 cm from the fecal pats, respectively. The mean number of eggs per gram of feces each month and animal body weight did not differ (p > 0.05) between the treated and control groups. Stool and soil samples from both groups were colonized by A. cladodes fungus and other fungi. Administration of Arthrobotrys cladodes var macroides mycelium by means of a sodium alginate matrix twice weekly reduced larval infestation of the surrounding pasture, indicating that this fungus may be a promising biological control of infecting forms of nematodes present in the environment.

Association of Infestation of Gastrointestinal Nematode With Altitudes of Location of Cattle Raising in Two Different Districts in Aceh Province

This study was aimed to measure the prevalence and the association of altitude of location of raising to the risk of infestation of gastrointestinal nematode in cattle. The study was conducted using cross sectional approach. A purposive sampling method was used to select the location of study (subdistricts and villages) in the two Districts. The inclusion criteria for the lowland were the location with altitude 200 m above sea level and the subdistricts (villages) of North Aceh District. The exclusion criteria for lowland was the location 200 m above sea level. Then, the inclusion criteria for the highland were the location with altitude 200 m above sea level and the subdistricts (villages) of Central Aceh District. The exclusion criteria for lowland was the location 200 m above sea level. A random sampling was used for selection of cattle for collecting faecal sample in two locations of study. A total number of 201 cattle, both male and female, were obtained for taking faecal sample from the two Districts. Faecal sample was examined for the existence of eggs of gastrointestinal nematode. The examination was conducted using floating method. Data were analyzed descriptively. The measurement of association of altitude of location of cattle raising and sex of animals to the risk of infestation of gastrointestinal nematode were analyzed using odds ratio (OR) estimation and continued with chi-square test. The results showed a higher prevalence of gastrointestinal nematode infestation in cattle of Lowland location (25%) as compared to Highland (5.8%). As for the altitude, the cattle raising in Lowland were more than 5 times higher risk for infestation of gastrointestinal nematode as compared to Higher land location (P0.005). The female cattle in Lowland was higher risk (6.18) for infestation than Highland (P0.01). A similar trend was obtained for male cattle which higher risk in Lowland (4.12) as compared to Highland, but it was not significant (P0.05). In conclusion, by considering the altitude of location, the cattle raising in Lowland were more than 5 times higher risk for infestation of gastrointestinal nematode as compared to Higher land location. There is a variation of risk between female and male cattle in different altitude.

In-vitro Anthelmintic Activity of Aqueous Extract of Leaves of Cleome Rutidosperma DC. (Capparidaceae) Against Haemonchus Contortus

Background: Cleome rutidosperma is annual herb found in different places in Bangladesh. Its leaves used as the treatment for Helminthiasis associated with Haemonchus contortus. This parasite is one of the most pathogenic nematodes and responsible for anemia, edema, and death of cattle’s, mainly during summer in warm, humid climates as like Bangladesh. The aim of the study to investigate the in-vitro anthelmintic activity of aqueous extract C. rutidosperma (AECR) leaves against H. contortus. Methods: We performed phytochemical analysis and in-vitro anthelmintic assay to determine the possible phytochemicals, caused by anthelmintic activity against H. contortus. Results: In-vitro anthelmintic assay, the AECR at the doses of 25; 50 and 100mg/mL significantly (p&lt; 0.01) and (p&lt; 0.001) paralyzed and caused the death of H. contortus in a dose-dependent manner. Reference standard drug Albendazole (15 mg/mL) exerts almost same effect as AECR. No paralyzed and death observed at the control group when treated with 0.9% normal saline. Conclusion: This data confirmed that the aqueous extract C. rutidosperma has the in-vitro anthelmintic activity of against H. contortus. C. rutidosperma may offer an alternative source for the control of gastrointestinal nematodes of cattle’s.

Concurrent treatment with a macrocyclic lactone and benzimidazole provides season long performance advantages in grazing cattle harboring macrocyclic lactone resistant nematodes

In 2013, a 118-day study was initiated to investigate the efficacy of concurrent treatment at pasture turnout with an injectable macrocyclic lactone with activity up to 28 days and an oral benzimidazole, referred to as “conventional” anthelmintics, when compared to treatment with conventional macrocyclic lactone alone or an injectable macrocyclic lactone with extended activity of 100 days or longer. A group of 210 steers were obtained from a ranch in California and transported to Idaho, USA. A total of 176 steers with the highest fecal egg counts were blocked by pre-treatment body weights and pasture location. A total of 44 pasture paddocks were assigned with 4 steers per paddock with 12 paddocks per therapeutic treatment group and 8 paddocks per controls. The four treatments were injectable doramectin (Dectomax®, Zoetis Inc., 0.2 mg kg−1BW, SC), injectable doramectin concurrently with oral albendazole (Valbazen®, Zoetis Inc., 10 mg kg−1BW, PO), extended release injectable eprinomectin (LongRange™, Merial Limited, 1 mg kg−1BW, SC) or saline. Cattle were individually weighed and sampled for fecal egg count on Days 0, 31/32, 61, 88, and 117/118 with an additional fecal sample on Day 14. At conclusion, one steer per paddock was euthanized for nematode recovery. The results from the first 32 days found evidence of macrocyclic lactone resistance against injectable doramectin and extended release eprinomectin. During this period the concurrent therapy provided nearly 100% efficacy based on fecal egg count reduction and a 19.98% improvement in total weight gain compared to controls (P = 0.039). At the conclusion of the 118-day study and past the approved efficacy for the conventional anthelmintics, the concurrent therapy with conventional anthelmintics provided a 22.98% improvement in total weight gain compared to controls (P = 0.004). The 118-day improvement in weight gain for the extended release eprinomectin group (29.06% compared to control) was not statistically different from the concurrent therapy with conventional anthelmintics. The results indicate that concurrent treatment with a conventional macrocyclic lactone and benzimidazole may provide production benefits early in the grazing period that continue throughout the entire period for cattle harboring macrocyclic lactone resistant nematodes. By using two different anthelmintic classes together, macrocyclic lactone resistant parasites were effectively controlled early in the period. Furthermore, the use of an effective conventional anthelmintic treatment regimen without an extended period of drug release may help to promote refugia and decrease the further selection for anthelmintic resistant parasites.

Biological control on gastrointestinal nematodes in cattle with association of nematophagous fungi

ABSTRACTThis study aimed to evaluate the efficacy of the association of the nematophagous fungi (Duddingtonia flagrans-AC001); (Pochonia chlamydosporia-VC4) and (Arthrobotrys robusta-I31) in a pelletised formulation of a sodium alginate matrix. The viability and activity of pellet germination and fungal activity (after encapsulation) were evaluated using in vitro and in vivo tests. Next, 12 heads of cattle, Dutch mestizo x zebu, with an average age of 12 months were dewormed with an anthelmintic. Next, 20 days after treatment with the anthelmintic, the animals were randomly divided into two groups of six animals each, and placed in two paddocks with 7.0 ha each of Brachiaria decumbens with historical grazing by animals naturally infected by gastrointestinal nematode parasites. At first, each animal was treated with 2 g of pellets per 10 kg of animal, containing the associated fungi (AC001 + VC4 + I31) administered twice a week in conjunction with commercial feed. Each animal in the control group received 2 g of pellets without mycelia added to the feed. The percentage reduction of infective larvae in the in vitro test was 94% (p < .01). In the in vivo test, the treated animals with fungal association had lower egg counts per gram of faeces (p < .01) compared to the control group animals – a reduction of 91.8%. The reduction in the number of infective larvae recovered from the pasture was 27.5% at a distance of 0–20 cm from the stool bulk, and 26.7% at a distance of 20–40 cm. This association (AC001 + VC4 + I31) of nematophagous fungi was effective in nematode control.

Evaluation of a refugia-based strategy in pastured Stocker cattle treated with LongRange®

Anthelmintic resistance (AR) in gastrointestinal nematodes of cattle is becoming increasingly prevalent worldwide, so there exists a need to develop novel approaches to manage and slow this progression. Refugia are the proportion of the worm population not selected by drug treatment, and the greater the proportion of the worm population left untreated (in refugia), the slower the progression of AR. Sources of refugia include worms in animals left untreated, stages of parasites not affected by the treatment, and free-living stages in the environment (e.g. eggs/larvae on pasture). Studies in sheep demonstrate that managing refugia will reduce the progression of AR without negatively impacting the health or productivity of the flock. However, many of these strategies are impractical for use with cattle, and consequently have not been tested or widely implemented in cattle. One refugia-based strategy with good potential applicability to the cattle industry is 'selective non-treatment’ where a percentage of the herd is deliberately left untreated. In this study, we examined the use of a selective non-treatment strategy in Stocker cattle.

Aspects of epidemiology and control of gastrointestinal nematodes in sheep and cattle – Approaches for its sustainability

Gastrointestinal helminthosis in ruminants cause considerable economic losses, with marked impairment of productivity of these animals, especially in poor management systems and poor parasite control programs. Infections caused by these helminths represent an obstacle to the expansion of the sheep industry. Furthermore, high parasite burdens were associated with increased mortality in calves. The recommended methods for the control of gastrointestinal helminths not always have practical applicability. We discuss important epidemiological and control aspects concerning gastrointestinal nematodes in sheep and cattle. Thus, sustainable worm control practices are recommended. Each farm has a specific situation and a management system directed to a specific parasitic infection must be adopted.

Comparative analysis of the immune responses induced by native versus recombinant versions of the ASP-based vaccine against the bovine intestinal parasite Cooperia oncophora

The protective capacities of a native double-domain activation-associated secreted protein (ndd-ASP)-based vaccine against the cattle intestinal nematode Cooperia oncophora has previously been demonstrated. However, protection analysis upon vaccination with a recombinantly produced antigen has never been performed. Therefore, the aim of the current study was to test the protective potential of a Pichia-produced double-domain ASP (pdd-ASP)-based vaccine against C. oncophora. Additionally, we aimed to compare the cellular and humoral mechanisms underlying the vaccine-induced responses by the native (ndd-ASP) and recombinant vaccines. Immunisation of cattle with the native C. oncophora vaccine conferred significant levels of protection after an experimental challenge infection, whereas the recombinant vaccine did not. Moreover, vaccination with ndd-ASP resulted in a higher proliferation of CD4-T cells both systemically and in the small intestinal mucosa when compared with animals vaccinated with the recombinant antigen. In terms of humoral response, although both native and recombinant vaccines induced similar levels of antibodies, animals vaccinated with the native vaccine were able to raise antibodies with greater specificity towards ndd-ASP in comparison with antibodies raised by vaccination with the recombinant vaccine, suggesting a differential immune recognition towards the ndd-ASP and pdd-ASP. Finally, the observation that animals displaying antibodies with higher percentages of recognition towards ndd-ASP also exhibited the lowest egg counts suggests a potential relationship between antibody specificity and protection.

Controlling gastrointestinal nematodes in cattle by Bacillus species

In this study, we tested the in vitro and in vivo larvicidal activity of Bacillus species against gastrointestinal nematodes in cattle, and their viability in the presence of anthelmintics. For in vitro tests, cattle feces naturally infected with trichostrongylides were incubated with spore suspensions of Bacillus circulans (Bcir), B. thuringiensis var. osvaldocruzi (Bto), B. thuringiensis var. israelensis (Bti) or B. thuringiensis var. kurstaki (Btk). Subsequently, residual larvae were counted and identified. All of the Bacillus species showed 60% or more larvicidal effects. Bcir and Bti were selected to be incubated with anthelmintics (moxidectin, nitroxynil and levamisole), and after 24, 72, and 144h, their viability was evaluated. Bti showed highest drug resistance, maintaining a concentration of 1×107CFU/mL. Based on this result, Bti was selected for in vivo tests on calves naturally infected with gastrointestinal nematodes. The calves were dived into four groups: Group 1, Bti suspension of ∼1×109CFU orally administered; Group 2, Bti suspension of ∼1×109CFU orally administered with levamisole (subcutaneously, 150mg); Group 3, only levamisole (subcutaneously, 150mg), and Group 4 untreated. Then 24 and 48h after treatment, larvae numbers were counted. We observed a reduction of 84%, 100%, and 100% after 48h of treatment, respectively, for Groups 1, 2 and 3 treatments in comparison with the untreated. The tested Bacillus species showed larvicidal activity against bovine trichostrongylides, and its association with anthelmintics. It may serve as a promising integrated alternative for control of gastrointestinal nematodes in cattle.

The use of nemabiome metabarcoding to explore gastro-intestinal nematode species diversity and anthelmintic treatment effectiveness in beef calves

Next-generation deep amplicon sequencing, or metabarcoding, has revolutionized the study of microbial communities in humans, animals and the environment. However, such approaches have yet to be applied to parasitic helminth communities. We recently described the first example of such a method – nemabiome sequencing – based on deep-amplicon sequencing of internal transcribed spacer 2 (ITS-2) rDNA, and validated its ability to quantitatively assess the species composition of cattle gastro-intestinal nematode (GIN) communities. Here, we present the first application of this approach to explore GIN species diversity and the impact of anthelmintic drug treatments. First, we investigated GIN species diversity in cow-calf beef cattle herds in several different regions, using coproculture derived L3s. A screen of 50 Canadian beef herds revealed parasite species diversity to be low overall. The majority of parasite communities were comprised of just two species; Ostertagia ostertagi and Cooperia oncophora. Cooperia punctata was present at much lower levels overall, but nevertheless comprised a substantive part of the parasite community of several herds in eastern Canada. In contrast, nemabiome sequencing revealed higher GIN species diversity in beef calves sampled from central/south-eastern USA and Sao Paulo State, Brazil. In these regions C. punctata predominated in most herds with Haemonchus placei predominating in a few cases. Ostertagia ostertagi and C. oncophora were relatively minor species in these regions in contrast to the Canadian herds. We also examined the impact of routine macrocyclic lactone pour-on treatments on GIN communities in the Canadian beef herds. Low treatment effectiveness was observed in many cases, and nemabiome sequencing revealed an overall increase in the proportion of Cooperia spp. relative to O. ostertagi post-treatment. This work demonstrates the power of nemabiome metabarcoding to provide a detailed picture of GIN parasite community structure in large sample sets and illustrates its potential use in research, diagnostics and surveillance.

Establishment rate of cattle gastrointestinal nematodes in farmed red deer (Cervus elaphus)

Red deer can be infected with some gastrointestinal nematodes (GIN) of cattle but it is unknown to what extent. An indoor study was conducted to determine the establishment rate of cattle GIN in young deer. Five young calves and 5 young red deer were used. They were effectively treated with anthelmintics when housed and then infected 2 weeks later. After four weeks they were killed for total worm counts. Establishment rates were assessed comparing worm counts to the infective dose which were identified morphologically, and to the relative establishment rate of different species. The establishment rates (%) in cattle and deer respectively were H. contortus (8.0, 18.7, p=0.18), Ostertagia ostertagi (30.8, 0.7, p<0.001), Cooperia spp. (72.3, 2.3, p<0.001) and Trichostrongylus spp. (19.0, 25.3, p=0.12). The majority (>98%) of Trichostrongylus spp. were Trichostrongylus axei in both hosts and there were no differences between hosts for this species (p=0.11). In cattle >98% of Cooperia were Cooperia oncophora and the mean burden was much higher than in deer (p<0.01) where there were similar proportions of Cooperia oncophora, Cooperia punctata and C. curticei. Small numbers of Oesophagostomum venulosum were also present with 3X as many found in deer as in cattle (p<0.05). This study has shown that some cattle-origin GIN can establish in red deer. In particular, the establishment of H. contortus and T. axei could allow sufficient burdens to build up to be clinically significant. Importantly, almost no cattle Ostertagia species or small intestinal species established in deer.

Prevalence of Gastrointestinal Nematoda in Cattle In Pintu Rime Gayo Highland of Bener Meriah Regency

This study was carried out to assess the prevalence of gastrointestinal nematode in cattle in the Pintu Rime Gayo, a highland sub district of Bener Meriah Regency, Aceh according to age and sex. Stool samples were collected from 150 cattle aged 0-6, 7-12 and 12 months old. Examination was performed by using a centrifuge. Samples tested positive when found gastrointestinal nematode parasite eggs. The data obtained were analyzed with Chi-Square. The results showed that the prevalence of gastrointestinal nematode in cattle aged 0-7 months (32%) was significantly higher (p0.05) than that in cattle aged 7-12 months (22%) and 12 months (12%). The parasite was markedly more prevalent (p0.05) in female cattle (23.9%) than that in male cattle (15.2%). In conclusion, susceptibility of cattle in the Pintu Rime Gayo highland to gastrointestinal nematode infection was influenced by both age and sex.

Utilization of composite fecal samples for detection of anthelmintic resistance in gastrointestinal nematodes of cattle

Recent reports indicate that anthelmintic resistance in gastrointestinal nematodes of cattle is becoming increasingly prevalent worldwide. Presently, the fecal egg count reduction test (FECRT) is the only means available for detection of resistance to anthelmintics in cattle herds at the farm level. However, the FECRT is labor and cost intensive, and consequently is only rarely performed on cattle farms unless for research purposes. If costs could be reduced, cattle producers might be more likely to pursue drug resistance testing on their farms. One approach to reducing the cost of the FECRT, is the use of composite fecal samples for performing fecal egg counts (FEC), rather than conducting FEC on fecal samples from 15 to 20 individual animals. In this study FECRT were performed on 14 groups of cattle using both individual and composite FEC methods To measure how well the results of composite sampling reproduce those of individual sampling, Lin’s Concordance Correlation Coefficient was utilized to describe both the linear relationship between methods and the slope and y-intercept of the line relating the data sets. There was little difference between the approaches with 98% agreement in mean FEC found between methods Mean FEC based on individual counts ranged between 0 and 670.6 eggs per gram of feces, indicating that the results of this study are applicable to a wide range of FEC levels. Standard error of the mean FEC and range of FEC are reported for each group prior to and following treatment to describe the variability of the data set. There was greater than 95% agreement in drug efficacy between individual and composite sampling methods, demonstrating composite sampling is appropriate to evaluate drug efficacy. Notably, for all groups tested the efficacy calculated by composite sampling was within the 95% confidence interval for efficacy calculated using individual sampling. The use of composite samples was shown to reduce the number of FEC required by 79%. These data demonstrate that pooling fecal samples from a group of cattle and then performing repeated FEC on that composite sample yields results very similar to performing individual FEC on those same animals, while substantially reducing the cost of performing a FECRT as compared to individual fecal samples. Furthermore, we have developed suggested methods for using composite samples in a FECRT, provided a cost comparison for this methodology, and described potential issues associated with the use of composite samples that must be considered.