Gastrointestinal nematodes and anthelmintic resistance in Danish goat herds

The prevalence of gastrointestinal parasites in Danish goats and the presence of anthelmintic resistance (AR) in 10 selected herds were investigated during April–September 2012. All Danish herds (n = 137) with 10 or more adult goats were invited to participate, and of these 27 herds met the inclusion criterion of more than 10 young kids never treated with anthelmintics. Questionnaire data on management were collected, and faecal samples from 252 kids were analysed by the McMaster technique. From all herds with a mean faecal egg count (FEC) above 300 eggs per g of faeces, pooled samples were stained with peanut agglutinin (PNA) for specific detection of Haemonchus contortus. Strongyle eggs were detected with an individual prevalence of 69%, including Nematodirus battus (3.6%) and other Nematodirus species (15.0%). Eimeria spp. were observed in 99.6% of the kids. H. contortus was found in 11 of 12 (92%) tested herds. Anthelmintics were used in 89% of the herds with mean treatment frequencies of 0.96 and 0.89 treatments per year for kids and adults, respectively. In 2011, new animals were introduced into 44% of the herds of which 25% practised quarantine anthelmintic treatments. In 10 herds the presence of AR was analysed by egg hatch assay and FEC reduction tests using ivermectin (0.3 mg/kg) or fenbendazole (10.0 mg/kg). AR against both fenbendazole and ivermectin was detected in seven herds; AR against fenbendazole in one herd, and AR against ivermectin in another herd. In conclusion, resistance to the most commonly used anthelmintics is widespread in larger goat herds throughout Denmark

Feeding chicory (Cichorium intybus) selectively reduces Ostertagia ostertagi infection levels in cattle

Objectives: Studies were conducted to test the potential use of chicory against gastrointestinal nematode infections in cattle. Methods: In study 1, fifteen 2-4 months-old dairy calves were allocated into a chicory (CHI, n=9) or control (CTL, n=6) group. CHI and CTL were stabled and fed with chicory silage or hay, resp., ad lib for 56 days. Protein/energy intakes were equalized between groups throughout the study. After 14 days on the diet all calves were infected with 10,000 Ostertagia ostertagi and 66,000 Cooperia oncophora third-stage (L3) larvae. In study 2, twenty 4-6 months-old dairy calves grazed a second-year, pure chicory sward (CHI, n=10) or a ryegrass/white clover pasture (CTL, n=10) for 43 days. After 7 days on the diet all calves were infected with 20,000 O. ostertagi L3. In both studies, individual live weights were recorded and faecal egg counts were calculated as number of eggs per g of dried feces (FECDM). At day 56 (study 1) calves were killed for worm recovery. Live weights and log-transformed FECDM were analysed by ANOVA using repeated measurements. Log-transformed worm counts were analysed by t-test. Results: In study 1 daily live weight gains were 500 and 329 g/day in CHI and CTL animals, resp. (p=0.02). Mean FECDM were not significantly different between groups (p=0.19). O. ostertagi geo mean worm counts were 1599 (± 296) and 3752 (± 258) in CHI and CTL groups, resp. (p0.05). From this point, egg excretion in CHI calves was significantly reduced and by day 36 post-infection FECDM was decreased by 48-65% compared to CTL (P<0.05). Discussion: Feeding on a chicory diet demonstrated a marked anthelmintic effect against O. ostertagi in both trials, whereas C. oncophora in study 1 was unaffected. Apparently, chicory does not interfere with worm establishment of O. ostertagi but significantly reduces egg excretion and adult worm counts. The lower weight gains in study 2 probably reflect lower energy consumption in this group and suggest that duration of grazing of pure chicory should be limited to selectively target established O. ostertagi adult populations

Condensed tannins in the gastrointestinal tract of cattle after sainfoin (Onobrychis viciifolia) intake and their possible relationship with anthelmintic effects

The fate of condensed tannins (CTs) along the digestive tract of ruminants is not well known and may account for the variable efficacy of CTs against gastrointestinal nematodes in different locations. Here, we analyzed sainfoin CTs in the digesta of cattle from two separate experiments. When using the acetone-butanol-HCl assay, the total CTs concentrations in the digestive tract were close to those in the diets (6.3 and 1.5% of DM in Expt. 1 and 2, resp.) indicating that CTs remained largely undegraded and unabsorbed. Yet with the thiolysis assay in Expt. 1, CTs concentration was much higher in the abomasum (2.3 ± 0.4 % of DM) compared with the rumen, small and large intestines, along with increases of mean size and percentage of prodelphinidins within CTs. This corroborates the anthelmintic efficacy reported only against Ostertagia ostertagi in the abomasum. In Expt. 2, no anthelmintic effect was observed against the larval exsheathment in the rumen, probably because the dietary level of CTs was too low. Overall, the level of CTs accessible to thiolysis in the gut appears to be critical for anthelmintic activity, which is favored under the acidic conditions of the abomasum

Antiparasitic activity of chicory (Cichorium intybus) and its natural bioactive compounds in livestock: a review

Increasing drug resistance in gastrointestinal (GI) parasites of livestock and concerns about chemical residues in animal products and the environment are driving the development of alternative control strategies that are less reliant on the use of synthetic drugs. An increasingly investigated approach is the use of bioactive forages with antiparasitic properties as part of the animal’s diet (nutraceuticals) or as potential sources of novel, natural parasiticides. Chicory (Cichorium intybus) is a multi-purpose crop and one of the most promising bioactive forages in temperate regions, and numerous in vivo trials have explored its potential against parasitic nematodes in livestock. However, it is unclear whether chicory can induce a direct and broad activity against various GI parasites in different livestock species, and the levels of chicory in the diet that are required to exert an efficient antiparasitic effect. Moreover, the mechanisms leading to the reported parasiticidal activity of chicory are still largely unknown, and its bioactive phytochemicals have only recently been investigated. In this review, we summarise the progress in the study of the antiparasitic activity of chicory and its natural bioactive compounds against GI parasites in livestock, through examination of the published literature. The available evidence indicates that feeding chicory can reduce faecal egg counts and/or worm burdens of abomasal nematodes, but not infections with intestinal worms, in ruminants. Highly chicory-rich diets (≥ 70% of chicory dry matter in the diet) may be necessary to directly affect abomasal parasitism. Chicory is known to synthesise several bioactive compounds with potential antiparasitic activity, but most research has been devoted to the role of sesquiterpene lactones (SL). Recent in vitro studies have confirmed direct and potent activity of SL-rich extracts from chicory against different GI helminths of livestock. Chicory SL have also been reported to exhibit antimalarial properties and its potential antiprotozoal activity in livestock remains to be evaluated. Furthermore, the detailed identification of the main antiparasitic metabolites of chicory and their pharmacokinetics need further confirmation. Research gaps and perspectives on the potential use of chicory as a nutraceutical forage and a source of bioactive compounds for parasite control in livestock are discussed

Prevalence of the protozoan parasite Cryptosporidium on three organic pig farms in Denmark

Pigs are potential sources of contamination with Cryptosporidium spp., which can lead to infection in humans. Cryptosporidiosis in humans is primarily caused by two species, C. hominis and the zoonotic C. parvum, however, other species including C. suis and C. scrofarum are able to cause zoonotic infection. The oocysts can survive for long periods in the environment and are able to resist most disinfectants. In order to estimate the prevalence of Cryptosporidium spp. in organic pigs and to improve knowledge of the epidemiology, the oocyst excretion was monitored at quarterly intervals during the period September 2011 to June 2012 in each of three organic, Danish pig farms. Faecal samples for examination of Cryptosporidium spp. were collected from 994 pigs allocated into four age groups, piglets (n = 161), weaners (n = 315), fatteners (n = 232) and sows (n = 286), distributed on the three farms and four sampling times. Oocysts were quantified by immunofluorescence microscopy, and the overall prevalence of Cryptosporidium spp. was found to be 38%. The prevalence varied significantly between age groups with 45% piglets, 65% weaners, 40% fatteners and 3% sows found positive. No significant difference in the overall prevalence was detected between farms or seasons. Intensity of infection was age dependent with piglets and weaners having the highest oocyst excretion. No clear differences in the intensity of infections were seen between the four sampling times, but an apparent correlation was observed between number of positive sows and number of piglets with massive oocyst excretion (>105 oocysts per gram faeces ( OPG). Nine of the ten animals with highest OPG originated from the same farm which also had the highest prevalence in sows. Molecular characterisation of the collected Cryptosporidium isolates is ongoing and will reveal the zoonotic potential as well as the genetic variation between farms, seasons and age groups