Differences In Faecal Egg Counts Research Articles

Pellets enriched with healthy hay and quebracho are not sufficient to control gastrointestinal nematodes in meat sheep commercial flocks.

The emergence of AH multiresistant GIN compromises sustainability of grassland sheep farming worldwide. Plants rich in condensed tannins are an alternative method of parasitism management that is currently being explored. Feed supplementation trials with pellets rich in sainfoin (Onobrychis viciifolia) and quebracho (Schinopsis spp.) were carried out. Three meat sheep farms in western France took part in the study and a total of 4 trials were carried out.During these 21-day trials, the ewes were returned to the sheepfold and half of them received a balanced ration supplemented with 70 g day−1 of healthy hay and quebracho pellets, while the other half received the same ration supplemented with 70 g day−1 of lucerne pellets. Fecal egg counts (FEC) were carried out at the start and end of each trial, and nematode species were identified by real-time PCR after larval culture. At D0, FEC were similar in both groups for all 4 trials. Proportions of species infecting the ewes varied from 1 trial to another: Haemonchus contortus was predominant in summer and Trichostrongylus colubriformis in winter. At D21, there were no significant differences in FEC between groups. Helminthofauna were not significantly different between groups, except for 1 trial where the proportion of H. contortus was reduced in the group supplemented with condensed-tannin pellets. The use of condensed tannins still requires additional studies to be advised as an effective method to manage gastrointestinal nematodes in farm.

Effect of Diatomaceous Earth on Growth Rate, Egg Production, Feed Conversion Efficiency and Parasitic Load in Hens Raised on Deep Litter

The efficacy of diatomaceous earth (DE) on growth rate, egg production and on increasing feed conversion efficiency in deep litter raised layer hens was evaluated. The study was conducted at Mukono Zonal Agricultural Research and Development Institute (MUZARDI) in Uganda. Worms were collected from fresh intestines of indigenous chicken obtained from Kalerwe chicken market near Kampala. The DE was mined in Pakwach (formerly Nebbi) district in Northern Uganda. Chickens of the Lohmann Brown breed raised on deep litter were studied. At 7 weeks the birds were divided into 5 treatment groups, A, B, C, D and E each composed of 40 birds. Groups C, D and E were given an oral dose containing 250 embryonated eggs of A. galli while groups A and B were not infected. The chicks were weighed; and subjected to feeding trials as arranged below: A – Non-infected birds on DE (4%) supplemented diet; B –non-infected birds on neither piperazine (a conventional de-wormer) nor DE; C – infected birds on DE supplemented diet; D – infected birds on piperazine; and group E – infected birds on neither DE nor piperazine applied. Fecal samples were collected and analysed in the laboratory biweekly at week 16 till week 22 respectively for fecal egg counts. In a subsequent experiment, day-old layer chicks from Lohmann Brown strain but different from those used in earlier experiments, were used to assess the effect of DE on egg production. At 17 weeks of age the 420 were divided as follows: 6 treatment groups each having 7 replicates and each replicate having 10 birds. This study showed that DE can be used successfully in growing pullet diets to correct nutritional mineral imbalance since it supplies more than 14 trace elements and other elements. Diatomaceous earth also enables pullets to cope with Ascaridia galli load; and 2% DE supplementation did not have significant improvement on egg production as compared to no supplementation at all. However, reduction in egg production was experienced when supplementation with levels of DE higher that 2% was applied. Results from biweekly fecal analyses showed significant differences in fecal egg counts (p<0.05); and treatment by group (p<0.05).

45 Effect of terminal sire breed on grazing performance, parasitism, and market grade of crossbred lambs: year 2

Abstract Improvements in growth and carcass conformation through terminal sire crossbreeding systems may improve lamb value in a pasture-based system. Therefore, the aim of this study was to replicate the previous model of this experiment and compare the effects of different terminal sires on parasitism, growth, composition and marketability of grazing lambs and lambs at weaning. Suffolk SU (n = 2) and Texel TX (n = 3) sires were mated to commercial ewes at the WVU Organic Farm. April-born lambs were managed as one group until weaning in mid-June. One group containing TX (n = 28) and SU (n = 22) was sold at weaning, the other group was sorted into 3 replicates per sire breed. Lambs were rotationally grazed for 62-d with paddock movements every 10-d. Lambs were supplemented at a rate of 2% of bodyweight with a 16% CP corn-soybean meal supplement. Weights and FAMACHA were collected at weaning and then weekly for the duration of the study. Fecal egg counts (FEC) and packed cell volumes (PCV) were collected bi-weekly. Lambs were dewormed when FAMACHA score was a 3 or greater. Ultrasound measures of rib eye area (REA) and fat depth were obtained at study conclusion and lambs were marketed at the same graded auction as the group sold at weaning. There was no significant difference in FEC and PCV data values during project duration (P = 0.32) (P = 0.19). Fewer deworming treatments were necessary in TX-sired lambs at 19% (7/36) whereas SU-sired lambs required 42% (15/36) (P = 0.04). REA and fat depth measurements were not significant between sired breeds (P = 0.21) (P = 0.50). Texel-sired lambs received a $0.26/Kg greater premium than the SU-sired lambs at weaning. Texel-sired lambs received a $0.29/Kg greater premium than the SU-sired lambs after the conclusion of grazing. These data demonstrate that Texel-sired lambs required fewer dewormer treatments and received premiums when marketed at a graded auction.

The Effects of Seasonality and Group Size on Fecal Egg Counts in Wild Przewalski's Horses (Equus Ferus Przewalskii, Poljakov, 1881) in The Chernobyl Exclusion Zone, Ukraine During 2014 - 2018.

SummaryThe aim of this study was to investigate the difference in Fecal Egg Counts (FEC) with regard to group size, age, sex and body condition of wild free-roaming Przewalski’s horses in the Chernobyl Exclusion Zone (Ukraine), across different seasons, over a five-year period (2014 – 2018). We hypothesized that horses from larger group sizes would have higher faecal egg counts (FECs). The relationship between FECs and the year and season of sample collection, and age, sex and group size of the horses was analyzed. Generalized linear model using positive strongylid FEC`s as a variable response, was used to investigate the differences in FECs between the groups.Nematode (Strondylidae, Parascaris spp., Habronematidae) and cestode (Anoplocephalidae) eggs were also identified. Stronglyids were the most prevalent helminth egg, and had the highest FECs.The model for egg counts of strongylids showed that season and group size of horses were statistically significant. Presence of strongylid eggs was not dependent on age and sex of horses. We suggest that this could be a result of parasite transmission between individuals and groups in places were animals aggregate around water sources or collective farms.Results obtained in this current study broaden the knowledge of gastrointestinal parasites in free-roaming horses under wild natural conditions.

Attempts to induce tolerance to Trichostrongylus colubriformis infection in sheep.

The possibility of manipulating the immune response in lambs to the gastrointestinal nematode Trichostrongyluscolubriformis to reduce production losses associated with infection was investigated. In a series of four experiments, attempts to immunize sheep via the mucosal route to modify the immune response and induce mucosal tolerance are outlined. Initially, a proof of concept study was conducted with lambs being injected with multiple doses of a somatic Tcolubriformis antigen without an adjuvant in the rectal submucosa and subsequently challenged with Tcolubriformis L3 larvae. This was followed by a dose-response study comparing different antigen doses to identify the optimum dose of the nematode antigen for successful induction of mucosal tolerance. The final two studies were conducted to determine the larval stage specificity of the parasite antigen and the most suitable site of delivery required to stimulate mucosal tolerance. In the proof of concept study, lambs either received repeated injections in the rectal submucosa at 3×weekly intervals with 15µg of L3, 11µg of L4 and 21µg of immature adult (L5) somatic Tcolubriformis antigens (ANT) or not (INF) prior to infection with Tcolubriformis. In the dose-rate study, antigen dose rates of 100%, 50%, 10%, 1% or 0% of the antigen concentration used in the proof of concept study were compared while the larval stage study compared antigen from either L3, L4, L5 stages or combination of all (COMB) and the route of administration study compared antigen delivery into either the rectal submucosa (RE) or sub-cutaneous injection (SC). During infection, lamb growth was improved by antigen treatment between days 21 and 42 in the proof of concept study (P=.009), for groups 10%, 50% and 100% in the dose-rate study (P<.05 for all) and in RE in the route of administration study with no improvement observed in the larval stage study. No differences in faecal egg counts were observed (P>.05 for all). Parasite-specific IgA and IgE showed a dose-response (the dose-rate study), were not affected by larval stage (the larval stage study) and were greater in RE than SC (the route of administration study). IL-4 production following lymphocyte stimulation was greatest in COMB (the larval stage study) and RE (the route of administration study). Although antigen treatment improved performance, this was inconsistent and appeared to stimulate immunity rather than induce tolerance. Combined larval stages were more efficient than individual stages, and intra-rectal administration was more effective than sub-cutaneous.

163 Annual differences in fecal egg counts in a forage-based ram test

Abstract The objective was to determine the magnitude of yearly differences in parasite load in growing ram lambs. Data were obtained from the Southwest Virginia Agriculture Research and Extension Center in Glade Spring, VA. The center conducts a forage-based ram growth test during the summer where rams also undergo a parasite challenge. Data consisted of 488 Katahdin rams tested from 2012 to 2018. Rams were dewormed at delivery, and at the start of the test, each ram received an oral dose of 5,000 H. contortus larvae adjusted for body weight. Fecal egg count was measured 70 d later when rams were on average (SD) 200 (18) d old. Fecal egg counts were not normally distributed. The Box-Cox procedure indicated that a log transformation was appropriate, but the residuals were not normally distributed for several linear models. A zero-inflated negative binomial generalized linear mixed model was used for data analysis with the glmmTMB package in R. The model included fixed effects of centered and scaled weight, centered and scaled age, year, birth type, and rearing type, and the random effect of consignor. Birth type, rear type, and age were not significant (P &amp;gt; 0.10). The least square mean (SE) fecal egg counts by year were 344 (118) for 2012, 623 (214) for 2013, 574 (195) for 2014, 1,125 (409) for 2015, 745 (253) for 2016, 408 (142) for 2017, and 239 (86) for 2018. Differences in summer precipitation could affect average parasite load. Despite similar total summer precipitation, 2012 had 1 extremely wet month whereas, 2015 had consistent precipitation throughout the summer. We conclude that producers should not compare fecal egg counts across years because the overall average may be multiple-fold different from year to year. Ranking rams within year will be more effective to select for improved parasite resistance.

Are sainfoin or protein supplements alternatives to control small strongyle infection in horses?

The spread of anthelmintic resistance in equine strongyle nematodes has become a major problem, advocating for the development of alternative control for strongyles. Our study consisted of both in vivo and in vitro experiments. We investigate for the first time the efficacy of a short-term consumption of tannin-rich sainfoin (Onobrychis viciifolia) or extra proteins in naturally infected horses. We used 30 horses allocated into three groups of 10 individuals that received for 18 days either (i) a tannin-rich diet with 70% DM sainfoin pellets (Sd), (ii) a protein-rich diet with 52% DM Italian rye-grass pellets and 18% DM grinded linseed expeller (Pd), or (iii) a control diet with 45% DM barley and 25% DM cereal-based pellets (Cd). The three diets were isoenergetic, covering 94% of animal energy requirements on average, and the Sd and Pd diets were isoproteic and provided extra proteins (227% of protein requirements v. 93% for the Cd diet). Pd and Cd were compared to test for benefits of receiving extra proteins, while Sd and Pd were compared to account for the effect of sainfoin secondary metabolites. There were no between-diet differences in faecal egg counts (FEC) or in worm burden evaluated from worm counts in faeces of drenched horses at the end of the experiment. However, coprocultures from the faeces collected in each group at the beginning and at the end of the experiment suggested a lower rate of strongyle larval development in the Sd group at the end of the experiment (Sd=8.1%, Pd=30.5%, Cd=22.6%). In vitro tests using sainfoin solutions evidenced the influence of sainfoin on strongyle larval development: adding 29% of sainfoin pellets to faeces reduced the strongyle egg development into infective larvae by 82% (P<0.001) and using solutions with sainfoin concentrations higher than 7.5 mg/ml reduced egg hatching by 37% (P<0.05). The short-term use of tannin-rich plants in horse diet could thus constitute a promising strategy to reduce the risk of infection by strongyles at pasture.

Multi-drug resistant Haemonchus contortus in a sheep flock in Antioquia, Colombia.

A sheep farm experiencing high lamb mortality and poor body conditions of ewes due to haemonchosis was tested for the presence of anthelmintic-resistant nematodes in August 2014. A fecal egg count reduction test was performed in Colombia on this farm and a DrenchRite® Larval development Assay (LDA) was shipped to the University of Georgia in the United States for resistance testing. The fecal egg count reduction test (FECRT) was conducted on 70 out of 500 animals allocated into five groups of 14 animals each: untreated control, albendazole (ABZ; 3.5mg/kg sc), ivermectin (IVM; 0.2mg/kg sc), moxidectin (MOX; 0.2mg/kg sc) and levamisole (LEV; 5mg/kg sc) plus triclabendazol/ivermectin (TBZ; 10mg/kg and IVM; 0.2mg/kg po). Individual fecal egg counts (FEC) using the modified McMaster technique and pooled larval cultures were performed 10days after anthelmintic treatment. Following 10days the initial results from the ABZ and IVM groups, 24 animals were treated twice with trichlorfon (TCF; 50mg/kg po) on days 0 and 6, and then checked for FEC on day 10. Mean differences in FEC before and after treatment were negligible (3 to 8% change) for the control, ABZ, LEV-TBZ and IVM groups. The MOX treatment resulted a mean FEC reduction of 76.7%, which was not-significant by t-test (p=0.08). The TCF treatment showed a mean FEC reduction of 42.3%, which was also not-significant (p=0.1). The DrenchRite® LDA was used to evaluate the resistance status to benzimidazole, levamisole, ivermectin and moxidectin on this farm. Coprocultures indicated that the predominant worm species was Haemonchus contortus (Colombia 94-100%) (UGA 77% H. contortus and 23% Trichostrongylus colubriformis). Resistance was evaluated for both H. contortus and T. colubriformis. The LDA results indicated high resistance to all 4 anthelmintics for both parasite species. The current study, together with similar surveys in 4 other Antioquian goat and sheep farms, confirms the presence of multi-drug resistant H. contortus to all three classes of anthelmintics in this region of Colombia.

Resistance to gastrointestinal parasite infection in Djallonké sheep

Gastrointestinal parasitism places serious constraints on small ruminant production. The situation has been exacerbated by development of drug resistance in many parasite populations, leading to interest in identification of animals with genetically mediated resistance or tolerance to nematode infections. This study assessed the response to natural infection with gastrointestinal nematodes (GIN) in Djallonké sheep during the rainy season in the Sudan-Guinea Savannah region of Burkina Faso. Haemonchus contortus is the most prevalent GIN at this site and time. Djallonké lambs (n=434) were sampled from 40 households and evaluated at a common location in southern Burkina Faso. Lambs were dewormed with levamisole at 2 to 6 months of age and returned to infected pastures. Fecal egg counts (FEC), packed cell volumes (PCV), and FAffa Malan CHArt (FAMACHA©) scores were determined 28 and 35 days after deworming. Lamb mortality was monitored throughout the experiment. Least-squares means for BW increased from 13.8±0.2 kg at 28 days to 14.0±0.2 kg at 35 days (P<0.01). Simple means and medians for FEC were 615 and 100, respectively, at 28 days and 850 and 175, respectively, at 35 days. The FEC exhibited strong right skewness. Following logarithmic transformation and back-transformation of resulting least-squares means to the original scale, FEC were higher (P<0.01) for males (208±27) than females (122±10). Least-squares means for PCV decreased (P<0.001) from 28 (36.3±0.5%) to 35 days (33.7±0.5%), and were higher (P<0.01) for females (36.0±0.4%) than males (33.9±0.7%). Correlations (r) between repeated measurements of BW, FEC, PCV and FAMACHA scores at 28 and 35 days were all positive (P<0.001). The correlation between FAMACHA scores and PCV was negative at 28 (r=−0.14) and 35 days (r=−0.18) (P<0.001). This study revealed that BW was an easily measured predictor of the ability of the lamb to resist infection with GIN and maintain PCV, and confirmed that FAMACHA scores are useful indicators of differences in FEC. Approximately 40% of female and 30% of male lambs did not show detectable levels of infection (i.e. FEC=0) under field conditions. The great variability that was observed in FEC and PCV suggests potential to use Djallonké sheep in breeding programs to enhance resistance to GIN.

Genetic variation for worm burdens in laying hens naturally infected with gastro-intestinal nematodes

Genetic parameters were determined for the worm burden of the most common gastro-intestinal nematodes in two chicken genotypes after being exposed to free-range farming conditions for a laying period.Seventeen-week-old hens of 2 brown genotypes, Lohmann Brown (LB) plus (n = 230) and LB classic (n = 230), were reared for a laying period and subjected to post-mortem parasitological examinations at 79 weeks (LB plus) or 88 weeks (LB classic) of age.There was no significant difference in faecal egg counts between the genotypes. Almost all hens (>99%) were infected with at least one nematode species. Species-specific nematode prevalence ranged from 85.8% to 99.1% between the two genotypes. Heterakis gallinarum was the most prevalent nematode (98.5%), followed by Ascaridia galli (96.2%) and Capillaria spp. (86.1%). Capillaria spp. were composed of C. obsignata (79%), C. caudinflata (16%) and C. bursata (5%).All phenotypic and genetic correlations among worm counts of different parasite species were positive in combined genotypes (rP ranged from 0.05 to 0.30 and rG ranged from 0.29 to 0.88). A strong genetic correlation (rG = 0.88 ± 0.34) between counts of A. galli and H. gallinarum was quantified. Heritability for total worm burden for LB plus and LB classic, respectively, were 0.55 ± 0.18 and 0.55 ± 0.34. Across both genotypes, the heritability of total worm burden was 0.56 ± 0.16.In conclusion, there is a high variation attributable to genetic background of chickens in their responses to naturally acquired nematode infections. The high positive genetic correlation between counts of closely related worm species (e.g. A. galli and H. gallinarum) may indicate existence of similar genetically determined mechanism(s) in chickens for controlling these nematodes.

Anthelmintic effect of three tannin-rich Mediterranean shrubs in naturally infected sheep

Gastrointestinal nematodes are recognized as some of the most important causes of production losses in extensive sheep farming. Due to the current trends and need for finding ecologically acceptable alternatives to chemically produced anthelmintics, many research efforts are focusing on secondary plant metabolites that showed promising anthelmintic effects (e.g. tannins). In this study we investigated the effect of a mixture of three tannin-rich Mediterranean shrubs (Arbutus unedo L., Pistacia lentiscus L. and Quercus ilex L.) on the fecal egg counts (FEC) of nematodes in naturally infected adult sheep. A total of 28 sheep was randomly assigned to a treated and control groups (n=14) and the effects of tannin-rich diet on FEC were evaluated throughout 30 days of study. No significant difference in FEC between the treated and the control group was noted at days 0, 23, and 30 of the study, suggesting that these three shrubs in combination do not exhibit a favorable antiparasitic effect for gastrointestinal nematodes in naturally infected sheep.

Effects of chicory/perennial ryegrass swards compared with perennial ryegrass swards on the performance and carcass quality of grazing beef steers.

An experiment investigated whether the inclusion of chicory (Cichorium intybus) in swards grazed by beef steers altered their performance, carcass characteristics or parasitism when compared to steers grazing perennial ryegrass (Lolium perenne). Triplicate 2-ha plots were established with a chicory/ryegrass mix or ryegrass control. Forty-eight Belgian Blue-cross steers were used in the first grazing season and a core group (n = 36) were retained for finishing in the second grazing season. The experiment comprised of a standardisation and measurement period. During standardisation, steers grazed a ryegrass/white clover pasture as one group. Animals were allocated to treatment on the basis of liveweight, body condition and faecal egg counts (FEC) determined 7 days prior to the measurement period. The measurement period ran from 25 May until 28 September 2010 and 12 April until 11 October 2011in the first and second grazing year. Steers were weighed every 14 days at pasture or 28 days during housing. In the first grazing year, faecal samples were collected for FEC and parasite cultures. At the end of the first grazing year, individual blood samples were taken to determine O. ostertagi antibody and plasma pepsinogen levels. During winter, animals were housed as one group and fed silage. In the second grazing year, steers were slaughtered when deemed to reach fat class 3. Data on steer performance showed no differences in daily live-weight gain which averaged 1.04 kg/day. The conformation, fat grade and killing out proportion of beef steers grazing chicory/ryegrass or ryegrass were not found to differ. No differences in FEC, O. ostertagi antibody or plasma pepsinogen levels of beef steers grazing either chicory/ryegrass or ryegrass were observed. Overall, there were no detrimental effects of including chicory in swards grazed by beef cattle on their performance, carcass characteristics or helminth parasitism, when compared with steers grazing ryegrass.

The effectiveness of faecal removal methods of pasture management to control the cyathostomin burden of donkeys.

BackgroundThe level of anthelmintic resistance within some cyathostomin parasite populations has increased to the level where sole reliance on anthelmintic-based control protocols is not possible. Management-based nematode control methods, including removal of faeces from pasture, are widely recommended for use in association with a reduction in anthelmintic use to reduce selection pressure for drug resistance; however, very little work has been performed to quantitatively assess the effectiveness of such methods.MethodsWe analysed data obtained from 345 donkeys at The Donkey Sanctuary (Devon, UK), managed under three different pasture management techniques, to investigate the effectiveness of faeces removal in strongyle control in equids. The management groups were as follows: no removal of faeces from pasture, manual, twice-weekly removal of faeces from pasture and automatic, twice-weekly removal of faeces from pasture (using a mechanical pasture sweeper). From turn-out onto pasture in May, monthly faecal egg counts were obtained for each donkey and the dataset subjected to an auto regressive moving average model.ResultsThere was little to no difference in faecal egg counts between the two methods of faecal removal; both resulted in significantly improved cyathostomin control compared to the results obtained from the donkeys that grazed pasture from which there was no faecal removal.ConclusionsThis study represents a valuable and unique assessment of the effectiveness of the removal of equine faeces from pasture, and provides an evidence base from which to advocate twice-weekly removal of faeces from pasture as an adjunct for equid nematode control. Widespread adoption of this practice could substantially reduce anthelmintic usage, and hence reduce selection pressure for nematode resistance to the currently effective anthelmintic products.

Weight gain-based targeted selective treatments (TST) of gastrointestinal nematodes in first-season grazing cattle

A three-year trial was performed in south-western Sweden to compare animal performance and levels of parasite control in three grazing groups, each with 18–24 first-season grazing (FSG) calves in similar set-stocked pasture enclosures. These groups were subjected to: (1) no parasite control (NT), (2) monthly repeated doramectin (Dectomax®) injections (SP), or (3) targeted selective weight gain-based anthelmintic treatments (TST) but only when individual calf performance was inferior to the average of the poorer 50% of those calves in group SP. In each year, weight and parasitological variables were measured at turn-out and then at predetermined intervals for 22–24 weeks during the grazing season. The dewormed calves in group SP had a higher average weight gain at housing (range 0.39–0.61kg/day) than those in TST (0.36–0.50kg/day), which in turn always exceeded the NT group (0.23–0.42kg/day). This indicates that the parasite challenge in the NT group was sufficiently high to result in production loss. However, the average cumulative faecal egg counts (FEC) at housing in NT were in the range 1271–1953 eggs per gram faeces (epg) and in TST 1221–1968epg. In contrast, parasite eggs were rarely recorded in group SP and then only during the first two years (on average 12 and 38epg). There were also no significant differences in FEC or serum pepsinogen levels between FSG in groups NT and TST. The animals in SP received 7 doses of doramectin each year, whereas those in TST received an average of 0.5 doses. Thus, the TST approach represented a 92% reduction in anthelmintic use. The average weight gain in animals subjected to TST was always significantly lower than in animals dewormed regularly. In addition, there were no signs of short-term selection for anthelmintic resistance in the group SP animals, despite the fairly intensive use of injectable doramectin.

Prevalence of nematode infection and faecal egg counts in free-range laying hens: relations to housing and husbandry

1. Faecal samples from 19 commercial, 65 week old free-range egg laying flocks were examined to assess the prevalence and number of parasitic nematode eggs. Data were collected to characterise the housing, husbandry, behaviour and welfare of the flocks to examine possible relationships with the egg counts. 2. Eggs of at least one genus of nematode were present in the faeces of all 19 flocks. Heterakis eggs were detected in 17 (89%) flocks, Ascaridia in 16 (84%), Trichostrongylus in 9 (47%), and Syngamus in 6 (32%). Faecal egg counts (FEC) were greatest for Ascaridia and Heterakis. 3. For each nematode genus, there was no significant difference in FEC between organic (N = 9) and non-organic (N = 10) flocks, or between static (N = 8) and mobile (N = 11) flocks. 4. FEC were correlated with a range of housing, husbandry and management practices which varied between the nematode genus and included depth of the litter, percentage of hens using the range, and number of dead hens. Statistical analysis indicated relationships with FEC that included light intensity above the feeder, indoor and outdoor stocking density, fearfulness in the shed and on the range, distance to the nearest shelter, and swollen toes. 5. None of the FEC for any of the genera was correlated with weekly egg production or cumulative mortality. 6. Although nematode FEC were highly prevalent among the flocks, the overall lack of relation to other welfare and production measures suggests that these infections were not severe.

Daily Variability of Strongyle Fecal Egg Counts in Horses

Strongyle parasites are ubiquitous in grazing horses and constitute a potential threat to equine health. Feces were collected from six horses four times daily over a period of 5 days. Fecal egg counts (FECs) were performed to identify any diurnal rhythms in strongyle egg shedding and to quantify variability at the different levels: individual horses, repeated counts, repeated subsamples, different time points, and different days. No significant differences in FECs were found between the different time points (P = .11). The variables—horse, day, subsample, and egg count—accounted for a variance of 104.83, 0.10, 7.24, and 5.61, respectively. The apparent lack of additional variability between the four different time points suggests that time of the day chosen for collecting fecal samples does not constitute a source of error in field studies. The majority of variability exists between different subsamples and repeated egg counts on the same subsamples, whereas the variability of FECs between following days can be considered negligible. The findings of this study have implication for designing and performing field surveillance of strongyle FEC levels and applying the FEC reduction test for evaluating anthelmintic efficacy.

A Comparison of the Sensitivity and Fecal Egg Counts of the McMaster Egg Counting and Kato-Katz Thick Smear Methods for Soil-Transmitted Helminths

BackgroundThe Kato-Katz thick smear (Kato-Katz) is the diagnostic method recommended for monitoring large-scale treatment programs implemented for the control of soil-transmitted helminths (STH) in public health, yet it is difficult to standardize. A promising alternative is the McMaster egg counting method (McMaster), commonly used in veterinary parasitology, but rarely so for the detection of STH in human stool.Methodology/Principal FindingsThe Kato-Katz and McMaster methods were compared for the detection of STH in 1,543 subjects resident in five countries across Africa, Asia and South America. The consistency of the performance of both methods in different trials, the validity of the fixed multiplication factor employed in the Kato-Katz method and the accuracy of these methods for estimating ‘true’ drug efficacies were assessed. The Kato-Katz method detected significantly more Ascaris lumbricoides infections (88.1% vs. 75.6%, p<0.001), whereas the difference in sensitivity between the two methods was non-significant for hookworm (78.3% vs. 72.4%) and Trichuris trichiura (82.6% vs. 80.3%). The sensitivity of the methods varied significantly across trials and magnitude of fecal egg counts (FEC). Quantitative comparison revealed a significant correlation (Rs >0.32) in FEC between both methods, and indicated no significant difference in FEC, except for A. lumbricoides, where the Kato-Katz resulted in significantly higher FEC (14,197 eggs per gram of stool (EPG) vs. 5,982 EPG). For the Kato-Katz, the fixed multiplication factor resulted in significantly higher FEC than the multiplication factor adjusted for mass of feces examined for A. lumbricoides (16,538 EPG vs. 15,396 EPG) and T. trichiura (1,490 EPG vs. 1,363 EPG), but not for hookworm. The McMaster provided more accurate efficacy results (absolute difference to ‘true’ drug efficacy: 1.7% vs. 4.5%).Conclusions/SignificanceThe McMaster is an alternative method for monitoring large-scale treatment programs. It is a robust (accurate multiplication factor) and accurate (reliable efficacy results) method, which can be easily standardized.

Fasciola hepatica: Comparison of the sedimentation and FLOTAC techniques for the detection and quantification of faecal egg counts in rats

We compared the sedimentation and FLOTAC techniques for the detection and quantification of Fasciola hepatica eggs in faecal samples obtained from 120 experimentally-infected rats before intervention, and in 42 rats after drug administration. Additionally, the average time for a single test was determined. A single FLOTAC showed a higher sensitivity (92.6%) than 2, 4 and 8 sedimentation readings (63.0–85.2%) for detecting F. hepatica eggs in rat faeces post-treatment. On average, it took 21 min to prepare and examine a single FLOTAC, whereas 114 min were needed for the sedimentation method including the reading of 8 slides. In both treated and untreated rats, the sedimentation method resulted in higher mean faecal egg counts (FECs) than FLOTAC ( P < 0.05). In view of the high sensitivity and efficiency, the FLOTAC technique holds promise for experimental work in the F. hepatica-rat model. Additional research is needed to determine the reasons for the observed differences in FECs.

The relative resistance to gastrointestinal nematode infection of three British sheep breeds

The relative resistance of Manx Loaghtan, Shetland and Southdown sheep to naturally acquired gastrointestinal nematode infection was assessed over a ten week period. Thirty shearling ewes, ten from each of the three breeds, were co-grazed on an infective pasture. The animals were initially treated with an anthelmintic to minimise previous nematode infection, and faecal samples were collected from individual animals every two weeks. Southdown sheep had significantly higher faecal egg counts (FEC) than Shetland by week 6, and than Manx Loaghtan by week 10. After ten weeks there was an 86-fold difference in FEC between Shetland and Southdown sheep, and a 14-fold difference between Manx Loaghtan and Southdown sheep. These preliminary results suggest that primitive Shetland and Manx Loaghtan sheep may have greater resistance to gastrointestinal parasites, a trait that could be of value to the UK livestock industry.

Association between variation in faecal egg count for a mixed field-challenge of nematode parasites and IGHA gene polymorphism

Research has shown that variation in ovine immunoglobulin A (IgA) levels are associated with reduced faecal egg counts (FECs) in sheep hosting gastro-intestinal (GI) parasites. Variation in the constant region of the ovine IgA heavy alpha chain gene ( IGHA) may result in structurally and functionally different IgA molecules and may consequently lead to variation in the IgA response to parasitisation. This study involved three sheep breeds (Merino, Polwarth and Corriedale) and a total of 2098 lambs from eight New Zealand farms that underwent a mixed field-challenge of nematode parasites. Faecal samples were taken at approximately 4 and 9 months of age and FECs for Nematodirus and Strongyle species determined along with total eggs per gram (EPG). Analysis of all eight farms collectively revealed no significant differences in FECs associated with the presence or absence of a particular IGHA allele. However, when the data was split into predominant challenge type groups, associations were detected. In 4-month-old lambs predominantly challenged by Nematodirus sp., the presence of the IGHA allele *01 was associated ( P < 0.05) with higher Strongyle FECs. In 9-month-old lambs predominantly challenged by Trichostrogylus sp., the presence of IGHA allele *02 was associated ( P < 0.006) with a higher mean total EPG at 9 months of age. These results suggest that IGHA gene variation will not be an effective gene-marker for reducing overall FEC but may be useful in defined or specific species challenges.