Interactions between nutrition and gastrointestinal infections with parasitic nematodes in goats

Effectiveness of benzimidazole treatments against Haemonchus contortus in sheep and goats - Do they produce similar responses?

The primary aim of this study was to compare the in vivo responses to orally administered doses of albendazole (5 mg/kg body weight) between experimentally infected sheep and goats. Fifty-four Improved Valachian lambs and 54 Saanen goat kids were split into six groups of nine animals. The sheep and goats were infected with larvae of the gastrointestinal nematode parasite Haemonchus contortus containing 10, 20, 30, 40, 60, and 80 % of the isotype-1 β-tubulin gene codon 200 alleles previously shown to be associated with benzimidazole (BZ)-resistance. All groups of goats generally had higher mean eggs per gram (EPG) before treatment, which was significant (p<0.05) only for the group with 80 % resistance alleles. An in vivo faecal egg reduction test (FECRT) was used to determine the efficacy of albendazole (ABZ) eight days after treatment. Anthelmintic treatment significantly reduced the EPGs in the groups with 10, 20, and 80 % resistance alleles in sheep and with 10, 20, 30, and 40 % resistance alleles in goats. Differences in efficacy between the sheep and goats after the application of doses of ABZ recommended for sheep mostly ranged from 2 % to 10 %. The largest variation was in the group infected with worms containing 60 % resistance alleles, where the efficacy was 13 % higher in goats. Our secondary aims were to evaluate the data obtained from an in vitro egg hatch test (EHT) in sheep and goats and to compare these data with the results from the isotype-1 β-tubulin gene codon 200 pyrosequencing and the FECRT. The percentages of the BZ-resistance alleles were comparable with the mean hatching obtained in the EHT and were also supported by the FECRT data for all groups. The results of the in vivo tests should be verified in the future using in vivo surveys conducted in mixed breeds and infections in multiple species.

Amino acid profiles, amino acid sensors and transporters expression and intestinal microbiota are differentially altered in goats infected with Haemonchus contortus

Infection with the nematode Haemonchus contortus causes host malnutrition and gastrointestinal injuries. The objective of this study was to investigate the effects of H. contortus infection on gastrointestinal contents of free amino acids (AA), the expression of AA transporters and microbiota with a focus on amino acid metabolism. Twenty-four Xiangdong black goats (13 ± 1.5 kg, 6 months old) were randomly assigned into the control group (n = 8) and the infected group (n = 16). The results showed that H. contortus infection increased (P < 0.05) the free AA contents in jejunum and ileum digesta. The concentrations of blood threonine, phenylalanine and tyrosine were lower (P < 0.05) in the infected group as compared to the control group. In the jejunum and ileum epithelium, H. contortus infection significantly (P < 0.05) down-regulated the expression of AA transporter b^0,+AT/rBAT and B0AT1, but up-regulated (P < 0.05) the expression of transporter CAT2 and xCT. Furthermore, microbiota in both jejunum (Bifidobacteriaceae, Lachnospiraceae, Bacteroidaceae, Enterobacteriaceae, and Micrococcaceae) and ileum (Acidaminococcaceae, Desulfovibrionaceae, Bacteroidaceae, and Peptostreptococcaceae) were also altered at the family level by H. contortus infection. The  commensal bacteria of jejunum showed a close correlation with amino acids, AA transporters, and amino acid metabolism, especially cystine. In conclusion, H. contortus infection affected the intestinal AA contents and the expression of intestinal AA transporters, suggesting altered AA metabolism and absorption, which were accompanied by changes in the relative abundances of gut bacteria that mediate amino acid metabolism.

Antiparasitic Tannin-Rich Plants from the South of Europe for Grazing Livestock: A Review

Internal parasites are one of the main causes of health threats in livestock production, especially in extensive livestock farming. Despite the environmental toxic effects (loss of dung beetles, biodiversity, and other issues) and resistance phenomenon derived from their prolonged use, anti-parasitic chemical pharmaceuticals are frequently used, even in organic farming. Such a situation within the context of climate change requires urgent exploration of alternative compounds to solve these problems and apparent conflicts between organic farming objectives regarding the environment, public health, and animal health. This review is focused on some plants (Artemisia spp., Cichorium intybus L., Ericaceae family, Hedysarum coronarium L., Lotus spp., Onobrychis viciifolia Scop.) that are well known for their antiparasitic effect, are voluntarily grazed and ingested, and can be spontaneously found or cultivated in southern Europe and other regions with a Mediterranean climate. The differences found between effectiveness, parasite species affected, in vitro/in vivo experiments, and active compounds are explored. A total of 87 papers where antiparasitic activity of those plants have been studied are included in this review; 75% studied the effect on ruminant parasites, where gastrointestinal nematodes were the parasite group most studied (70%), and these included natural (31%) and experimental (37%) infections.

Ecological drivers of helminth infection patterns in the Virunga Massif mountain gorilla population

The Virunga Massif mountain gorilla population has been periodically monitored since the early 1970s, with gradually increasing effort. The population declined drastically in the 1970s, but the numbers stabilized in the 1980s. Since then, the population has been steadily increasing within their limited habitat fragment that is surrounded by a dense human population. We examined fecal samples collected during the Virunga 2015-2016 surveys in monitored and unmonitored gorilla groups and quantified strongylid and tapeworm infections using egg counts per gram to determine environmental and host factors that shape these helminth infections. We showed that higher strongylid infections were present in gorilla groups with smaller size of the 500-m buffered minimum-convex polygon (MCP) of detected nest sites per gorilla group, but in higher gorilla densities and inhabiting vegetation types occurring at higher elevations with higher precipitation and lower temperatures. On the contrary, the impact of monitoring (habituation) was minor, detected in tapeworms and only when in the interaction with environmental variables and MCP area. Our results suggest that the Virunga mountain gorilla population may be partially regulated by strongylid nematodes at higher gorilla densities. New health challenges are probably emerging among mountain gorillas because of the success of conservation efforts, as manifested by significant increases in gorilla numbers in recent decades, but few possibilities for the population expansion due to limited amounts of habitat.

Nematicidal effect of a lectin preparation from Artocarpus heterophyllus (Moraceae) on larvae and adults of Haemonchus contortus

Haemonchus contortus is a hematophagous parasite that causes damage to ruminant production worldwide. This study reported the in vitro nematicidal effect of a lectin preparation (LP) isolated from Artocarpus heterophyllus seeds on larvae and adults of H. contortus. The protein extraction was in phosphate-buffered saline followed by protein precipitation with ammonium sulfate 70% and dialysis. The dialyzed protein fraction was chromatographed to obtain isolated LP. The LP was characterized by hemagglutinating activity (HA) assays, protein dosage and polyacrylamide gel electrophoresis. The motility index of H. contortus in the third larval stage (unsheathed L3 larvae) and adult stage was evaluated. The HA inhibition of LP by mannose and galactose as well as the electrophoretic profile indicated the presence of the lectins ArtinM and Jacalin. The motility index of H. contortus was significantly reduced (p < 0.001) during the first 8 h of LP exposure, both in larvae (lowest index 8.3% with LP at 1 mg mL-1) and female adults (lowest index 20% with LP at 500 μg mL-1; index 40% with LP at 1 mg mL-1). This research revealed that the LP has potential for being utilized in the development of natural nematicides.

Metabolizable energy balance in hair sheep lambs artificially infected with Haemonchus contortus

In sheep, infection with Haemonchus contortus may increase the need for energy, and this demand may vary according to the infection level. In this study, the energy intake, digestibility, and energy retention of lambs artificially infected with different levels of H. contortus were estimated. A total of 24 hair sheep lambs reared parasite-free were experimentally infected with H. contortus at one of three infection levels: non-infected (n = 6); infected with 300 infective larvae (L₃) of H. contortus/kg body weight (BW) (n = 9); and infected with 500 H. contortus L₃/kg BW (n = 9). The lambs were fed for an individual weight gain of 100 g/day, and intake of organic matter (OMI) and gross energy (GEI), digestible (DEI) and metabolizable energy (MEI) were measured weekly. The digestibility of organic matter (OMD) and GE (GED) and the metabolizable energy (ME) balance adjusted to zero nitrogen balance (ME_adj) were measured for each lamb during the prepatent and patent periods of infection. From day 21 post-infection (PI), the individual eggs per gram (EPG) of feces and the total number of eggs in feces (TEF) were estimated weekly. After humane slaughter on day 42 PI, the worm burden (WB) was determined. Correlation and regression analyses were performed to estimate the relationships between the parasitological variables (L₃, EPG, TEF and WB) and the response variables (OMI, GEI, DEI, MEI, OMD, GED, ME_adj). During the prepatent period, there were no significant relationships of L₃ with the response variables (OMI, GEI, DEI, MEI, OMD, GED, ME, ME_adj). Similarly, during the patent period, no relationship was evident between infection (EPG, TEF or WB) and OMI, GEI, DEI, GED, OMD, ME or ME_adj. Thus, the gradient of H. contortus infection examined in the present study did not influence energy balance in hair sheep lambs, and infection did not impose any detectable energy cost. Further studies are needed to fully assess the impact of H. contortus infection on energy metabolism in hair sheep.

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 (0.5 ml/25 kg bwt) (positive control 1), the third group was given albendazole (2.5 mg active principle/kg bwt) (positive control 2), and the fourth group was given PPE (200 mg/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 (7 days 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.

Unravelling the anthelmintic bioactives from Jasminum grandiflorum L. subsp. Floribundum adopting in vitro biological assessment

ETHNOPHARMACOLOGICAL RELEVANCE

Jasminum grandiflorum L. is a medicinal plant widely used in the traditional system of Medicine as an anthelmintic in ringworm infections, for treating ulcers, stomatitis, skin diseases, and wounds.

AIM OF THE STUDY

The emergence of resistance by different parasites to currently used chemicals has been reported. There are increasing needs for more effective and safer parasiticides. Therefore, the current study was designed to investigate the methanolic extract of the aerial parts of J. grandiflorum subsp. Floribundum (JGTE) to confirm its traditional uses as anthelmintic through a bioassay-guided fractionation and isolation of the active components with anthelmintic activity.

MATERIALS AND METHODS

The JGTE was partitioned into dichloromethane (DCM-F) and n-butanol (BuOH-F) fractions. The JGTE, fractions, and the isolated compounds were tested in vitro for their anthelmintic activity using two nematodes; one larval stage of cestode and one arthropod. Four major compounds were isolated from the most active fraction (BuOH-F) including two flavonoids and two secoirridoid glycosides, identified as kaempferol-3-O-neohesperoside (1), rutin (2), oleuropein (3), and ligstroside (4).

RESULTS

Among the isolated compounds from most active fraction (BuOH-F), rutin (2) displayed the highest anthelmintic activity in a dose-dependent activity with IC₅₀ of 41.04 μg/mL against H. muscae adult worm, followed by ligstroside (4) with IC₅₀ of 50.56 μg/mL.

CONCLUSIONS

These findings could advocate the traditional use of J. grandiflorum L. and provide further insight into the anthelmintic activity of flavonoids.

Dietary protein degradability effect on performance of lambs experimentally infected with Haemonchus contortus and Trichostrongylus colubriformis

The study investigated the effects of dietary protein degradation rate on growth performance and immune response of crossbred Dorper × short-tail Han ram lambs experimentally infected with Haemonchus contortus and Trichostrongylus colubriformis. Eighteen lambs were randomly assigned to three dietary treatments, rapidly degradable protein (RDP), moderately degradable protein (MDP), and slowly degradable protein (SDP) diets. Feed intake and body weight of the lambs were recorded weekly until 42 days post-infection. The fecal egg count (FEC), FAMACHA scores, and immunoglobulins (IgG, IgM and IgA) were also monitored during the experimental period. A metabolic trial was conducted to assess apparent digestibility and volatile fatty acids were also determined. The lambs in SDP and MDP groups had higher feed, nutrient intake, weight gain, and feed efficiency than those in the RDP group. Feed conversion ratio (FCR) of the lambs in RDP group was higher than those in the SDP and MDP groups. A significant (P < 0.001) decrease in FEC was observed in the SDP and MDP groups. Dietary treatment had no significant effect on FAMACHA scores and concentration of serum antibodies. Concentration of acetic acid was higher (P < 0.013) in the lambs fed RDP than those fed the SDP and MDP diets. The lambs fed SDP diet had higher apparent digestibility than those fed the RDP diet. The poor performances in RDP group could be overcome by including SDP that ensures adequate post-ruminal protein supply reaching the small intestine.

Traditional Latvian herbal medicinal plants used to treat parasite infections of small ruminants: A review

Numerous treatment agents offering prophylaxis against livestock parasites are commercially available. However, because of increasing antiparasitic drug resistance, the increased popularity of environmentally friendly lifestyle choices, and organic farming, there is more demand for new alternatives to livestock anthelmintic control strategies and medications. It is important to develop antiparasitics that are safe, effective, inexpensive, and environmentally safe. Local, traditional herbal plants such as tansy, mugwort, wormwood, and heather may serve as treatments for intestinal parasites of sheep. This overview provides knowledge of traditional Latvian plants with antiparasitic activities to establish a database for further research to develop new herbal antiparasitic drugs.

In-vivo anthelmintic activity assessment to dietary incorporation of natural feed additives in sheep: A comparative study

Anthelmintic activity to dietary incorporation of exogenous fibrolytic enzymes (EFE) and wormwood (Artemisia absinthium L.) herb as feed additives was evaluated. Twenty crossbred lambs (11.58±0.01 kg body weight) were distributed into four dietary treatments in completely randomized design and fed for a period of 90 days followed by 6 day digestibility trial. Animals in all the groups were offered oats straw based total mixed ration added with EFE’s cocktail at 0.60% substrate dry matter (DM) level (T1) or wormwood herb at 4.50% substrate DM level (T2) either alone, and in-combination of the two feed additives (T3), whereas the TMR without addition of any additive served as control (T0). In vivo anthelmintic assays and selected haemato-biochemical parameters of animals were evaluated at start (0d) and subsequently at monthly intervals (30, 60 and 90d). The feed additives in-combination improved nutrient digestibility and digestible nutrient intakes per day. Wormwood herb inclusion had significant positive effect on overall treatment means as well as at each feeding period of per cent faecal egg count reduction and at 90 day period of faecal parasitic eggs per gram assay. Blood profile revealed better physiological health status of lambs fed feed additives compared to those of control group. It is concluded that incorporation of wormwood had better anthelmintic activity and the two feed additives act synergistically in sheep to improve nutrient utilisation and gastrointestinal infested host’s health.

The effect of plant bioactive compounds on lamb performance, intake, gastrointestinal parasite burdens, and lipid peroxidation in muscle

Plant extracts have been widely used in animal production systems due to the benefits promoted by their bioactive components, mainly through their antioxidant effects and positive effects on animal growth, health, and meat quality. We determined whether bioactive compounds (BC) from grape (Vitis vinifera), olive (Olea europaea), and pomegranate (Punica granatum) have beneficial effects on lamb growth while controlling gastrointestinal parasitism and reducing skeletal lipid peroxidation in muscle. Fourteen lambs (4 to 5 mo of age) were housed in individual pens and assigned to two treatment groups (seven animals/group), where they received: 1) a basal diet of beet pulp:soybean meal (90:10) (CONTROL) and 2) the same diet, but containing 0.3% of BC extracted from grape, olive, and pomegranate (BNP). After 21 d of consuming their respective rations (period 1), all lambs were dosed with 10,000 L3 stage larvae of Haemonchus contortus. Intake, production, and physiological parameters were determined before infection (period 1), after oral dosage with L3 (period 2), and during early (period 3) and later (period 4) developmental stages of infection. Groups of animals did not differ in their ration intake or average daily gain, either before or after the infection, or in their parasitic burdens estimated through fecal egg counts (P > 0.05). Lambs under BNP showed greater feed efficiency before infection (P < 0.001), but the pattern reversed after infection. In addition, the inclusion of plant bioactives to the diet did not have an effect (P > 0.05) on blood or lipid peroxidation in muscle or on hemogram, serum concentration of haptoglobin, and immunoglobulin E. These results could be explained by low dietary doses and constrained absorption or ruminal inactivation of these compounds. Changes in feed efficiencies suggest a negative interaction between BC in the diet and parasitism, which warrants further research.

Prevalence and fecal egg load of gastrointestinal parasites of Angora goats in four agro-ecological zones in Lesotho

Background and Aim:

Goats are reared for their meat, mohair and other socio-cultural needs in Lesotho. Helminth infections are some of the major setbacks in the goat production industry due to their negative impact on animals’ health, resulting in significant losses on meat and mohair production and death. A cross-sectional study was conducted to determine the prevalence, fecal egg infestation, and morphological identification of gastrointestinal parasites in goats.

Materials and Methods:

Fecal samples were collected from 765 goats and subjected to McMaster egg counting techniques using the flotation method. Statistical analyses were performed using the Statistical Package for the Social Sciences (SPSS v.26.0).

Results:

The overall prevalence of gastrointestinal parasites was 94.7%, and the identified gastrointestinal parasites were nematodes (64.7%), coccidia (25.8%), and cestodes (4.2%). Haemonchus contortus was identified as the prevalent gastrointestinal nematode species found in goats. The prevalence and fecal egg count of gastrointestinal parasites were significantly higher (p<0.05) in goats located in the highlands and Senqu River Valley, while goats in the lowlands demonstrated a significantly (p<0.05) higher prevalence of H. contortus. Immature goats and kids were more significantly (p<0.05) prone to gastrointestinal parasites.

Conclusion:

The nematodes and coccidia infestations were prevalent in goats located in the highlands and foothills, respectively, whereas nematode and coccidia fecal egg loads were higher in goats located in the foothills and Senqu River Valley, respectively.

Tannin supplementation modulates the composition and function of ruminal microbiome in lambs infected with gastrointestinal nematodes

This study was carried out to evaluate the effects of tannin supplementation on ruminal microbiota of sixteen lambs infected and non-infected with Haemonchus contortus and Trichostrongylus colubriformis. Animals were fed with hay, concentrate and supplemented with Acacia mearnsii (A. mearnsii). The animals were divided into four treatments: two control groups without infection, either receiving A. mearnsii (C+) or not (C-), and two infected groups, one with A. mearnsii (I+) and another without A. mearnsii (I-). Ruminal short-chain fatty acids (SCFA) and metagenome sequencing of ruminal microbiota were used to evaluate the effect of tannin and infection on ruminal microbiome. For SCFA, differences were observed only with A. mearnsii. Total SCFA and acetate molar percentage were decreased in C+ and I+ (P<0.05). Butyrate, valerate and isovalerate were higher in lambs that received A. mearnsii in the diet (P<0.05). The infection changed the microbiome structure and decreased the abundance of butyrate-producing microorganisms. In addition, A. mearnsii supplementation also affected the structure the microbial community, increasing the diversity and abundance of the butyrate-producing and probiotics bacteria, amino acid metabolic pathways, purine, pyrimidine and sphingolipid metabolism. Together, our findings indicate that A. mearnsii supplementation modulates important groups related to nitrogen, amino acid, purine and pyrimidine metabolism, in rumen microbiome, affected by gastrointestinal nematodes infection in lambs.

The Electrophoretic Pattern of Serum Proteins in Sheep with Naturally Acquired Gastrointestinal Nematode Infections

The objective of this study was to describe the serum protein pattern in sheep with naturally acquired gastrointestinal parasitosis and to compare the distribution of protein fractions with the results obtained in animals with negative fecal examination results. Fecal and blood samples were taken from twenty-nine sheep positive for nematode eggs and twenty-four animals with negative results of fecal examination. Between the evaluated groups of sheep significant differences were noted in the relative mean values for all protein fractions and for albumin/globulin ratio (p<0.01 and p<0.001). The concentrations of total proteins showed no significant differences between both groups of sheep. The absolute mean values of albumin, α2-globulins and A/G ratio were significantly lower, the mean concentrations of α1-, β-, γ1- and γ2-globulins significantly higher in the nematode positive group of sheep (p<0.01 and p<0.001). In the nematode positive group the protein electrophoretic pattern showed a double α2-zone in three sheep and the γ-globulin zones were characterized by a diffuse higher broad and wide peaks. The presented results indicate that the gastrointestinal parasitic infections in sheep alter the distribution of serum proteins, and suggest their usefulness in animals with unchanged serum protein concentrations. The study brings new findings and extends the knowledge about the metabolic responses and consequences of gastrointestinal parasitic infections in sheep, particularly with regard to alterations in protein metabolism.

Hydro-Ethanolic Extract of Mentha pulegium Exhibit Anthelmintic and Antioxidant Proprieties In Vitro and In Vivo

INTRODUCTION

During recent decades, the emergence of chemoresistance among synthetic anthelmintic drugs has increased the interest in screening novel natural anthelmintic compounds derived from plants. The current study is aimed to determine the chemical profile, anthelmintic and antioxidant properties of Mentha pulegium hydro-ethanolic extract.

MATERIALS AND METHODS

Two tests were used to assess the in vitro anthelmintic activity of the hydro-ethanolic extract of M. pulegium against Haemonchus contortus; egg hatch assay (EHA) and adult worm motility (AWM) assay. M. pulegium extracts at the doses of 500, 1000, 2000 and 4000 mg/kg were evaluated in vivo in mice infected with Heligmosomoides polygyrus. The anthelmintic efficacy was monitored using faecal egg count reduction (FECR) and total worm count reduction (TWCR). The antioxidant activity of M. pulegium extract was evaluated by testing the total antioxidant capacity and the DPPH free radical-scavenging ability.

RESULTS

Chromatographic characterization of M. pulegium composition using RP-HPLC revealed the presence of phenolic acids such as syringic acid, ferulic acid and the presence of flavonoid compounds, such as isorhamnetin-3-O-glucoside and kaempferol-3-O-rutinoside. We observed 91.58% inhibition in the EHA at 8 mg/mL after 48 h of incubation (IC50=1.82 mg/mL). In the AWM assay, M. pulegium extract achieved 65.2% inhibition at 8 mg/mL after 8 h. The highest dose (4000 mg/kg) showed a significant nematicidal effect 7 days post-treatment by inducing 60.39% FECR and 71.6% TWCR. We also report strong in vivo antioxidant capacity of the extract, as revealed by a significant increase of the enzymatic activities of catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GPx) enzymes in mice infected with H. polygyrus.

CONCLUSION

Together, the results in this paper suggest that M. pulegium possesses anthelmintic properties and could be a potential source of novel compounds for the control of helminth parasites as well as its associated oxidative damage.

Frequency of Resistance to Benzimidazoles of Haemonchus contortus Helminths from Dairy Sheep, Goats, Cattle and Buffaloes in Greece

The study investigated the presence of resistance to benzimidazoles in Haemonchus contortus helminths from ruminant species in Greece through the detection of the Phe/Tyr polymorphism in the amino acid at position 200 of the β-tubulin protein. In total, 288 adult female H. contortus helminths collected from the abomasum of various ruminant animals in Greece were tested. Of these, 96 were collected from sheep, 96 from goats, 48 from cattle, and 48 from buffaloes. The frequencies of the homozygous and heterozygous resistant genotypes at the position 200 of the β-tubulin gene of helminths recovered from sheep were 96.9% and 3.1%, respectively. The frequencies of the homozygous and heterozygous resistant genotypes, respectively, were 100.0% and 0.0% in helminths from goats, 25.0% and 75.0% in helminths from cattle and 8.3% and 91.7% in helminths from buffaloes. In all parasitic populations, no homozygous susceptible genotypes were detected. The present study highlighted, for the first time, the emergence of benzimidazole-resistant H. contortus in goats, cattle, and buffaloes in Greece, using an allele-specific PCR. It is postulated that benzimidazole-resistant alleles were transferred from sheep or goats to cattle and buffaloes at the commonly grazing pastures in Greece.

Kinetics of IgA and eosinophils following a low-dose, predominantly Haemonchus contortus infection of Boer goats

AIMS

Most breeds of goat are more susceptible to nematode infection than sheep, and this appears to be a consequence of less effective immune responses. Several papers have considered the effectiveness of eosinophils and immunoglobulin A (IgA) in goats but differences in the induction of responses have not been studied in the same detail. The aim of this study was to look at the induction of eosinophil and IgA responses in Boer goats reared indoors under intensive conditions.

METHODS AND RESULTS

The goats were experimentally infected with a low dose of 2400 Haemonchus contortus, Trichostrongylus spp. and Oesophagostomum spp. at a 6:1:1 ratio. Faecal egg counts (FEC), packed cell volume (PCV), IgA activity against third-stage larvae and peripheral eosinophilia were measured twice a week for eight weeks. The infection generated an IgA response but did not significantly increase peripheral eosinophilia in the 25 infected kids compared with the 4 control animals. FEC was not associated with IgA activity or eosinophilia.

CONCLUSION

A detailed analysis of IgA and eosinophil responses to deliberate nematode infection in Boer goats showed that there was an increase in nematode-specific IgA activity but no detectable eosinophil response. In addition, there was no association between increased IgA activity or eosinophilia with egg counts and worm burdens. These suggest that IgA and eosinophils do not act to control nematode infection in goats.

Anthelmintics in the future: current trends in the discovery and development of new drugs against gastrointestinal nematodes

The control of gastrointestinal nematodes (GINs), the most abundant and serious parasites of livestock, has become difficult because of the limited number of available drugs and fast development of drug resistance. Thus, considerable efforts have been devoted to developing new anthelmintics that are efficient against nematodes, especially resistant species. Here, we summarize the most recent results using various approaches: target-based or high-throughput screening (HTS) of compound libraries; the synthesis of new derivatives or new combinations of current anthelmintics; the repurposing of drugs currently approved for other indications; and lastly, the identification of active plant products. We also evaluate the advantages and disadvantages of each of these approaches.

Implication of the fecal egg count reduction test (FECRT) in sheep for better use of available drugs

Abstract The aim here is to present data on the efficacy of anthelmintics in sheep flocks in Rio de Janeiro, Brazil, and to discuss the interpretation of the fecal egg count reduction test (FECRT) for each nematode genus. Fecal eggs counts and pre- and post-treatment coprocultures were performed, the former to evaluate the efficacy of and the latter to determine the overall parasite prevalence. An additional efficacy test was performed at Farm # 1 a year after the initial test. Severe anthelmintic resistance was found for the flocks, with no FECRT sensitivity at any of the 22 farms evaluated. However, an analysis of the infective larvae showed that some drugs were effective against certain parasitic genera; i.e., levamisole was more effective against Haemonchus spp. and moxidectin against Trichostrongylus spp. In the additional FECRT performed at Farm # 1, moxidectin and nitroxynil were ineffective separately, but when applied in combination they were highly effective due to their efficacy against Haemonchus (nitroxynil) and Trichostrongylus (moxidectin), respectively. The use of the FECRT targeting the parasitic nematode species prevalent on farms may make it possible to choose more effective anthelmintics.

Assessment of Haemonchus contortus larval and adult somatic antigens in sero-diagnosis of haemonchosis in naturally infected sheep and goats

The current work was carried out to evaluate the potency of larval and adult somatic Haemonchus contortus (H. contortus) antigens in detection of haemonchosis among sheep and goats using ELISA. Two hundred and forty-three fecal and blood samples were randomly collected from small ruminants (107 sheep and 136 goats) in Beni-Suef Governorate, Egypt, during the period from June to August 2018. The fecal analysis exhibited that 26.33% of the small ruminants were infected with gastrointestinal nematodes. The overall prevalence of H. contortus was reached 22.22% whereas it was 27.10% and 18.38% among sheep and goats, respectively. The current study elucidated that the larval antigen has claimed more superior diagnostic results compared to the adult somatic H. contortus antigen. The apparent overall sero-prevalence among small ruminants was reached 51.85%. Separately, it was 64.48% in sheep and 41.91% in goats. The larval antigen had proved 96.55% sensitivity and 47.43% specificity, for sheep serum samples. Meanwhile, sensitivity and specificity for goats' sera were 100% and 71.17%, respectively. Diagnostic efficacy of ELISA was recorded 60.74% in sheep and 76.47% in goats. This study deduced that the larval antigen has proved the priority and the potency for diagnosis of H. contortus infection. Moreover, haemonchosis is a prevalent disease among the examined sheep and goats.

Impact of gastrointestinal parasitism on dry matter intake and live weight gain of lambs: A meta-analysis to estimate the metabolic cost of gastrointestinal nematodes

This study aimed to estimate the effect of gastrointestinal nematodes (GIN) on the productive performance assessed by the live-weight change (LWC) of lambs, and the metabolic cost associated with parasitism by means of a meta-analysis. Data used in the meta-analyses were obtained from twenty papers selected using the following criteria: (a) lambs with (I) and without (NI) GIN; (b) lambs fed ad libitum; (c) LWC data; (d) feed consumption data; and (e) chemical composition of diets. The effect of diet composition (crude protein [CP] and metabolizable energy [ME]) on dry matter intake (DMI), and the effect of composition and nutrient intake (DMI and CP intake [CPI]) and ME intake (MEI) on LWC was evaluated using respective regression analyses. The metabolic cost of worm burden was determined as the difference in CP and ME requirements between NI and I lambs for each adult parasite. The CP and ME cost were evaluated for lambs at two different levels: maintenance level 0 g LWC and 100 g LWC. The worm burden had an impact on the DMI and LWC of lambs (P < 0.05). The association of CP x infection level was the best predictor of DMI. The association between MEI and infection level were the best predictors of LWC. The metabolic cost of GIN increased to 0.30 mg CP/kg LW^0.75 and 0.0056 kJ ME/kg LW^0.75 for each adult parasite. The metabolic cost was not modified by diet quality (maintenance level 0 g LW/day or 100 g LW/day). In conclusion, GIN has a negative effect on DMI and LWC. The metabolic cost of GIN infection can be covered by supplying the additional requirements for protein and energy in the diet of infected lambs.

Supplementation with dry Mimosa caesalpiniifolia leaves can reduce the Haemonchus contortus worm burden of goats

Gastrointestinal nematodes (GINs) cause considerable economic losses in grazing goat herds. At present, GIN control cannot rely on conventional anthelmintic (AH) drugs because parasites have developed resistance against such drugs. Thus, alternative control methods are being sought to reduce the dependence on AH. Many tannin-rich plants exhibit AH activity and may be used as alternatives for GIN control. Mimosa caesalpiniifolia is a tannin-rich shrub consumed by small ruminants in Brazil. This study evaluated the in vivo AH effect of M. caesalpiniifolia leaf powder supplementation on GIN egg fecal excretion and worm burden in goats. Plant leaves were harvested, dried and ground to obtain a powder. Twenty-four castrated male goats, aged six to eight months, with a mean body weight of 15.0 ± 2.5 kg were used in the experiment. Animals were infected orally with 16,000 larvae comprising 50% Haemonchus spp., 41% Trichostrongylus spp. and 9% Oesophagostomum spp. Once the infection was patent, the goats were distributed into four groups of six animals. The control group received concentrate without condensed tannins (CTs) and did not receive any drench against GINs. The monepantel group received concentrate without CTs and were drenched once with monepantel. The other two groups received the M. caesalpiniifolia leaf powder in two periods of seven consecutive days (days 1-7 and 14-21), with one of the groups also receiving 10 g of polyethyleneglycol (PEG)/day. The animals were weighed weekly, and individual fecal eggs counts (FECs) were performed daily. After 28 days, the animals were humanly slaughtered, and the worm burden was estimated. Although live weight gain and FECs did not differ among the groups (P > 0.05), post-mortem worm counts showed a reduction in Haemonchus contortus adult worm burden (57.7%) in goats of the CT group compared to control goats (P < 0.05). The addition of PEG did not diminish AH activity in the CT + PEG group (66.9% reduction compared to the control). No AH effect against other GIN species was found. The result for the addition of PEG suggested that the observed AH activity was associated with plant secondary compounds, as opposed to CTs. As expected, no AH effect against Oesophagostomum columbianum was found for the monepantel group showed. Thus, feeding dry leaves of M. caesalpiniifolia represent a promising alternative for the control of GIN infections in goats.

Serum biochemistry panels in African buffalo: Defining reference intervals and assessing variability across season, age and sex

Serum biochemical parameters can be utilized to evaluate the physiological status of an animal, and relate it to the animal's health. In order to accurately interpret individual animal biochemical results, species-specific reference intervals (RI) must be established. Reference intervals for biochemical parameters differ between species, and physiological differences including reproductive status, nutritional resource availability, disease status, and age affect parameters within the same species. The objectives of this study were to (1) establish RI for biochemical parameters in managed African buffalo (Syncerus caffer), (2) assess the effects of age, sex, pregnancy, and season on serum biochemistry values, and (3) compare serum biochemistry values from a managed herd to a free-ranging buffalo herd and to values previously published for captive (zoo) buffalo. Season profoundly affected all biochemistry parameters, possibly due to changes in nutrition and disease exposure. Age also affected all biochemical parameters except gamma glutamyl transferase and magnesium, consistent with patterns seen in cattle. Sex and reproductive status had no detectable effects on the parameters that were measured. The biochemical profiles of managed buffalo were distinct from those observed in the free-ranging herd and captive buffalo. Biochemical differences between buffalo from captive, managed, and free-ranging populations may be related to nutritional restriction or lack of predation in the context of management or captivity. The reference intervals provided in this study, in addition to the seasonal and age-related patterns observed, provide a foundation for health investigations that may inform management strategies in this ecologically and economically important species.

The effect of different levels of crude protein on the pathophysiology of Haemonchus contortus infection in 2-year-old Boer dry does under confined conditions

The effect of dietary protein supplementation on the pathophysiology of a single Haemonchus contortus infection in 2-year-old Boer dry does under confined conditions was examined. Twenty-four does were randomly confined in individual pens and allocated into three groups balanced by their liveweight. The goats in the Control group were offered a basal diet whereas goats in Treatments 1 and 2 were fed the basal diet plus 25% and 50% dietary protein increments, respectively. Each animal was orally administrated 100 H. contortus L3 larvae/kg liveweight on Day 0 of the experiment. The goat liveweights and FAMACHA scores were recorded at weekly intervals. Packed cell volumes, eosinophil percentage, haemoglobin concentration, total serum protein, globulin, and albumin concentrations were recorded on Days 0 and 14, and then at weekly intervals during the experiments. Faecal egg counts were measured on Days 0, 21, and then at weekly intervals thereafter. Antigen-specific IgA, IgG, and IgM titres were determined from Enzyme-linked immunosorbent assays tests on Days 0, 28, and at the termination of the experiment. The results of this study showed that a single H. contortus L3 infection did not cause pathogenic effects in 2-year-old Boer dry does. Dietary protein supplementation significantly lowered faecal egg count and significantly enhanced IgG titres (P < 0.05). However, the higher protein diets did not have any significant effects on liveweight, packed cell volumes, haemoglobin concentration, biological parameters (total serum protein, albumin, and globulin concentrations), and peripheral antibodies (IgA and IgM titres) between the treatments. Further investigations are required to clarify the role of protein supplementation to control H. contortus infection in goats.

Evaluation of anthelmintic activity of biologically synthesized silver nanoparticles against the gastrointestinal nematode, Haemonchus contortus

The present study focuses on the in vitro anthelmintic activity of silver nanoparticles (AgNPs) synthesized using the aqueous extract of Azadirachta indica against Haemonchus contortus. The synthesized AgNPs were characterized by ultraviolet-visible (UV-Vis) spectrophotometry, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD) studies. The UV-Vis spectrum exhibited a sharp peak at 420 nm, which was validated by electron microscopy, indicating the preparation of spherical nanoparticles measuring 15-25 nm in size. The in vitro study was based on an egg hatch assay (EHA) and adult motility inhibition assays. Six concentrations of AgNPs were used for EHA, ranging from 0.00001 to 1.0 μg/ml, and a range of 1-25 μg/ml was used for adult worms. The highest concentration induced 85 ± 2.89% egg hatch inhibition. The IC50 value for EHA was 0.001 μg/ml, whereas in vitro adult H. contortus motility inhibition was produced at 7.89 μg/ml (LC50). The effectiveness of A. indica leaf extract (aqueous) was also evaluated, which showed an IC50 value for EHA of 115.67 μg/ml, while the LC50 against adult H. contortus was 588.54 μg/ml. The overall findings of the present study show that the experimental plant extract contains reducing properties for the synthesis of AgNPs which, in turn, showed potent anthelmintic properties. This is the first report where AgNPs have been tested for their anthelmintic properties in an in vitro model.

Interactions Between Nutrition and Infections With Haemonchus contortus and Related Gastrointestinal Nematodes in Small Ruminants

Interactions between host nutrition and feeding behaviour are central to understanding the pathophysiological consequences of infections of the digestive tract with parasitic nematodes. The manipulation of host nutrition provides useful options to control gastrointestinal nematodes as a component of an integrated strategy. Focussed mainly on the Haemonchus contortus infection model in small ruminants, this chapter (1) illustrates the relationship between quantitative (macro- and micro-nutrients) and qualitative (plant secondary metabolites) aspects of host nutrition and nematode infection, and (2) shows how basic studies aimed at addressing some generic questions can help to provide solutions, despite the considerable diversity of epidemiological situations and breeding systems.

The 'Toolbox' of strategies for managing Haemonchus contortus in goats: What's in and what's out

A dynamic and innovative approach to managing the blood-consuming nematode Haemonchus contortus in goats is critical to crack dependence on veterinary anthelmintics. H. contortus management strategies have been the subject of intense research for decades, and must be selected to create a tailored, individualized program for goat farms. Through the selection and combination of strategies from the Toolbox, an effective management program for H. contortus can be designed according to the unique conditions of each particular farm. This Toolbox investigates strategies including vaccines, bioactive forages, pasture/grazing management, behavioural management, natural immunity, FAMACHA, Refugia and strategic drenching, mineral/vitamin supplementation, copper Oxide Wire Particles (COWPs), breeding and selection/selecting resistant and resilient individuals, biological control and anthelmintic drugs. Barbervax(®), the ground-breaking Haemonchus vaccine developed and currently commercially available on a pilot scale for sheep, is prime for trialling in goats and would be an invaluable inclusion to this Toolbox. The specialised behaviours of goats, specifically their preferences to browse a variety of plants and accompanying physiological adaptations to the consumption of secondary compounds contained in browse, have long been unappreciated and thus overlooked as a valuable, sustainable strategy for Haemonchus management. These strategies are discussed in this review as to their value for inclusion into the 'Toolbox' currently, and the future implications of ongoing research for goat producers. Combining and manipulating strategies such as browsing behaviour, pasture management, bioactive forages and identifying and treating individual animals for haemonchosis, in addition to continuous evaluation of strategy effectiveness, is conducted using a model farm scenario. Selecting strategies from the Toolbox, with regard to their current availability, feasibility, economical cost and potential ease of implementation depending on the systems of production and their complementary nature, is the future of managing H. contortus in farmed goats internationally and maintaining the remaining efficacy of veterinary anthelmintics.

Comparing different maize supplementation strategies to improve resilience and resistance against gastrointestinal nematode infections in browsing goats

The effect of maize grain supplementation on the resilience and resistance of browsing Criollo goat kids against gastrointestinal nematodes was evaluated. Five-month-old kids (n = 42), raised worm-free, were allocated to five groups: infected + not supplemented (I-NS; n = 10), infected + maize supplement at 108 g/d (I-S108; n = 8), maize supplement at 1% of body weight (BW) (I-S1%; n = 8), maize supplement at 1.5% BW (I-S1.5%; n = 8), or infected + supplemented (maize supplement 1.5% BW) + moxidectin (0.2 mg/kg BW subcutaneously every 28 d) (T-S1.5%; n = 8). Kids browsed daily (7 h) in a tropical forest for 112 days during the rainy season. Kids were weighed weekly to adjust supplementary feeding. Hematocrit (Ht), hemoglobin (Hb), and eggs per gram of feces were determined fortnightly. On day 112, five goat kids were slaughtered per group to determine worm burdens. Kids of the I-S1.5% group showed similar body-weight change, Ht and Hb, compared to kids without gastrointestinal nematodes (T-S1.5%), as well as lower eggs per gram of feces and Trichostrongylus colubriformis worm burden compared to the I-NS group (P > 0.05). Thus, among the supplement levels tested, increasing maize supplementation at 1.5% BW of kids was the best strategy to improve their resilience and resistance against natural gastrointestinal nematode infections under the conditions of forage from the tropical forest.

Growth and carcass attributes of growing Creole kids according to experimental infection level and type of diet

In the tropics one of the major constraints to goat production is infection by gastrointestinal nematodes (GIN). One promising alternative to chemotherapy is the improvement of host nutrition. The aim of this study was to assess the effects of infection and supplementation on packed cell volume (PCV), average daily gain (ADG) and carcass quality in growing Creole kids. Sixty male goats were reared indoors following a 2 × 3 factorial design: two experimental infection levels, (infected (I) and non-infected (NI)) and three diets D (G, kids were fed exclusively with tropical forages; B, kids were supplemented with dried and crushed banana and C, kids were supplemented with commercial pellets). Faecal egg counts did not vary among I groups (on average 2,200 ω/g). The PCV and ADG were improved (P < 0.001) for NI vs. I animals. There was a D effect (P < 0.001) and no I × D interaction was observed. There was no significant effect of GIN on the main carcass data, except the weights of liver, white offal and abdominal fat, which increased slightly in I compared with NI goats (P < 0.05). All carcass data increased significantly with the addition of supplement in the diet (P < 0.001), except for carcass-cut proportions. Meat physical parameters were degraded when I kids received low N diets (B or G) with higher lightness and water loss than in the C groups. Given that GIN affect the animal's N metabolism it is recommended to avoid the use of unbalanced diet such as those banana-based. Further research is necessary to assess the nutrition × parasitism interactions on physiological features and carcass quality of Creole goats.

Effects of dietary supplementation with green tea polyphenols on digestion and meat quality in lambs infected with Haemonchus contortus

Ujumqin sheep are susceptible to infection by the gastrointestinal nematode Haemonchus contortus, which reduces productivity and total meat yield in sheep. Thus, the effects of green tea polyphenol (GTP) supplements (0, 2, 4, or 6g of GTP/kg feed) on dietary nutrient digestibility and meat quality in lambs infected with H. contortus were examined; control lambs were not infected. H. contortus infections did not affect digestion but the apparent digestibilities of nutrients were decreased by dietary 2g of GTP/kg feed supplementation. There was an interaction between treatment and sampling time on plasma total protein, urea nitrogen, and amino acid concentrations. The antioxidant activity and meat color of INFGTP0 lambs decreased. In conclusion, H. contortus infections in lambs decreased meat quality, but appropriate levels of dietary GTP supplementation diminished these negative effects though lower dose of GTP supplement showed negative effects on digestion.

Fasciola hepatica infection and association with gastrointestinal parasites in Creole goats from western Argentina

Goats, called “the cow of the poor”, are the livestock species with the most significant population growth worldwide in recent years. Gastrointestinal parasitism constitutes one of the main constraints to its outdoor and extensive breeding in temperate and tropical countries. Despite a Creole goat population of nearly 4 million heads, local reports on parasitological prevalence are scarce, and while Fasciola hepatica infection is spread all over Argentina, the goat is usually neglected as a reservoir and economic losses are not considered. To evaluate gastrointestinal parasitism prevalence and associations between parasite genera and species, with emphasis on fascioliasis, Creole goats from the plateau and Andean regions from western Argentina were investigated by coprological techniques, and associations were statistically assessed. Eighty-five percent (85%) of the animals harbored one or more parasite types, while 46% showed mixed infections. Significant positive associations between F. hepatica + Strongyle eggs, Eimeria sp. + Nematodirus sp. and Nematodirus sp. + Trichuris ovis were detected. Further studies are required to define the causality of these associations and their relevance in epidemiology. F. hepatica is rarely considered as goat parasite in the country, but a 33% prevalence poses an interrogation on the role goats play on the transmission and dissemination of this zoonotic trematode.

Investments on Pro-poor Development Projects on Goats: Ensuring Success for Improved Livelihoods

The elements that determine the success of development projects on goats and the prerequisites for ensuring this are discussed in the context of the bewildering diversity of goat genetic resources, production systems, multifunctionality, and opportunities for responding to constraints for productivity enhancement. Key determinants for the success of pro-poor projects are the imperatives of realistic project design, resolution of priorities and positive impacts to increase investments and spur agricultural growth, and appropriate policy. Throughout the developing world, there exist 97% of the total world population of 921 million goats across all agro-ecological zones (AEZs), including 570 breeds and 64% share of the breeds. They occupy a very important biological and socio-economic niche in farming systems making significant multifunctional contributions especially to food, nutrition and financial security, stability of farm households, and survival of the poor in the rural areas. Definitions are given of successful and failed projects. The analyses highlighted in successful projects the value of strong participatory efforts with farmers and climate change. Climate change effects on goats are inevitable and are mediated through heat stress, type of AEZ, water availability, quantity and quality of the available feed resources and type of production system. Within the prevailing production systems, improved integrated tree crops - ruminant systems are underestimated and are an important pathway to enhance C sequestration. Key development strategies and opportunities for research and development (R and D) are enormous, and include inter alia defining a policy framework, resolution of priority constraints using systems perspectives and community-based participatory activities, application of yield-enhancing technologies, intensification, scaling up, and impacts. The priority for development concerns the rainfed areas with large concentrations of ruminants in which goats, with a capacity to cope with heat tolerance, can be the entry point for development. Networks and networking are very important for the diffusion of information and can add value to R and D. Well formulated projects with clear priority setting and participatory R and D ensure success and the realisation of food security, improved livelihoods and self-reliance in the future.

In vitro screening of forty medicinal plant extracts from the United States Northern Great Plains for anthelmintic activity against Haemonchus contortus

An egg hatch assay (EHA) and a larval migration assay (LMA) involving Haemonchus contortus was used to evaluate the anthelmintic activity of methanol extracts from 40 plants that are native or naturalized within the U.S.A. Northern Great Plains. Only one of these 40 plants (i.e. Lotus corniculatus) had been previously evaluated for activity against any gastrointestinal nematode. The various extracts were initially screened at 50mg/ml diluted either in 0.5% dimethyl sulphoxide (DMSO) or 3-(N-morpholino) propanesulfonic acid (MOPS buffer), and plants showing 100% inhibition at 50mg/ml, were further evaluated at 8 other concentrations (25-0.19 mg/ml). Extracts with 100% activity with the EHA were again screened with the LMA (50mg/ml). Two extracts with the highest LMA inhibition were also evaluated at lower concentrations (25-3.1mg/ml). Of the 40 methanolic extracts screened, 7 (Chrysothamnus viscidiflorus, Ericameria nauseosa, Liatris punctata, Melilotus alba, Melilotus officinalis, Perideridia gairdneri, and Sanguinaria canadensis) showed significant egg-hatch inhibition in DMSO and MOPS buffer. Three extracts (Geranium viscosissimum, L. corniculatus, and Rhus aromatica) only showed significant inhibition in DMSO. The 8 extracts showing 100% efficacy at 50mg/ml exhibited dose-dependent effects at the 8 lower concentrations, and R. aromatica and E. nauseosa extracts had the lowest ED50 values. Similarly, when these 8 plant extracts were further evaluated with the LMA, the extracts of E. nauseosa and R. aromatica again exhibited the highest activity (p<0.001), with ED50 values of 4.0mg/ml and 10.43 mg/ml respectively. Three other extracts (C. viscidiflorus, M. alba and M. officinalis) also showed inhibitory activity in the LMA. These results support the need for additional evaluations of the nematocidal properties for at least these 5 plants.

Maize supplementation of Pelibuey sheep in a silvopastoral system: fodder selection, nutrient intake and resilience against gastrointestinal nematodes

This trial evaluated the effect of maize supplementation on the ingestive behavior, nutrient intake and the resilience against gastrointestinal nematode (GIN) infection of hair sheep in a silvopastoral system containing tropical grasses and legume trees. In addition, it attempted to determine the metabolic cost of the natural GIN infection in supplemented and non-supplemented animals. Twenty-nine 3-month-old lambs (male and female), raised nematode free, were allocated to four groups: I-NS (infected, not supplemented, n = 8), I-S (infected, supplemented with maize at 1.5% live weight (LW), n = 7), T-NS (treated with moxidectin 0.2 mg/kg LW every 28 days, and not supplemented, n = 7) and T-S (treated with moxidectin and supplemented with maize at 1.5% LW, n = 7). During the 70-day trial, fodder intake, fodder selection, LW change (LWC), red blood cell counts (RBC), hemoglobin (Hb), hematocrit (Ht) and eggs per gram of feces (EPG) were measured every 14 days. Supplement consumption was recorded daily. Metabolizable energy (ME) and protein (MP) consumption from the feeds were estimated. Maize supplementation helped to improve the resilience of hair sheep lambs against GIN infections. The I-S and T-NS groups showed similar LWC, RBC, Hb and Ht (P > 0.05) and both were higher than those in the I-NS group (P < 0.05). No difference was found in EPG between the I-NS and the I-S groups (P > 0.05). No effect of sex was observed in the different variables. Although all groups showed low dry matter intake (DMI) (< 2% LW), supplemented groups (T-S and I-S) showed higher total DMI (fodder + maize; P < 0.05), hence higher ME and MP intakes than the non-supplemented groups (T-NS and I-NS). All groups showed similar fodder selection patterns. The estimated metabolic cost of parasitism was ME = 0.70 MJ/day and MP = 9.2 g/day in the I-S animals. Meanwhile, the cost in the I-NS animals was ME = 1.46 MJ/day and MP = 12.71 g/day. Maize supplementation was an economically viable strategy to control GIN compared with no intervention.

Risk factors relating to helminth infections in cows during the peripartum

The aim of this study was to investigate whether season, lactation number, breed standard and milk production were risk factors relating to occurrences of gastrointestinal nematodes in dairy cows during the peripartum period. Eighty-four cows were randomly selected through proportional stratified sampling. In order to analyze the fecal egg per gram (EPG) count, the data were subjected to the Spearman test, Kruskal-Wallis test at 5% significance and linear regression. At the time of calving, the cows showed high EPG counts in relation to all variables analyzed. Among the animals studied, we observed that purebred Holstein cows at their first lactation and with high milk production showed high EPG counts (600) and comprised the group most at risk within the herd studied. In this group, the animals showed moderate EPG during the prepartum period (300) and a significant increase (p < 0.01) in EPG count from the time of calving (900), i.e. an increase of the order of 300%. Selection of animals for milk production in tropical countries should be based not only on productive potential, but also on adaptive features.

Manipulating small ruminant parasite epidemiology through the combination of nutritional strategies

It is increasingly being recognized that non-chemical parasite control strategies may need to be combined to control more effectively gastrointestinal parasitism, result in resilient production systems and reduce reliance on anthelmintics. Here, we consider if and how metabolizable protein (MP) supplementation and anti-parasitic plant secondary metabolites (PSM) may modulate parasite epidemiology through intervention in pasture contamination, development of infection on pasture and larval challenge as target processes. We then propose that combining two or more non-chemical parasite control strategies may have additive effects on host resistance, especially if the individual strategies target different drivers of parasite epidemiology, different processes in the parasite life cycle or different phases of acquired immunity to parasites. This epidemiological framework is used to review recent findings on combining maternal MP supplementation and grazing the PSM-rich bioactive forage chicory as an example of combining nutritional treatments to manipulate parasite epidemiology in a temperate production system. In the absence of available data for combined nutritional strategies in tropical production systems, we make predictions on the consequences of combining such strategies in these systems. We conclude that currently published studies on combining nutritional strategies under temperate conditions show potential to improve additively host resilience and reduce reliance on anthelmintics; however, effects on epidemiology have to date not shown the additive results hypothesized. The framework developed may assist further in evaluating combined (nutritional) strategies to manipulate parasite epidemiology.

Effects of host diet and thermal state on feeding performance of the flea Xenopsylla ramesis

We examined feeding performance of the flea Xenopsylla ramesis on three different hosts: its natural, granivorous, rodent host, Sundevall’s jird (Meriones crassus); the frugivorous Egyptian fruit bat (Rousettus aegyptiacus); and an insectivorous bat, Kuhl’s pipistrelle (Pipistrellus kuhlii). Because these fleas are not known to occur on bats, we hypothesized that the fleas’ feeding performance (i.e. feeding and digestion rates) would be higher when feeding on their natural host than on either of the bats that they do not naturally parasitize. We found that mass-specific blood-meal size of both male and female fleas was significantly lower when feeding on Kuhl’s pipistrelles than on the other two species, but was not different in female fleas feeding on fruit bats or on jirds at all stages of digestion. However, more male fleas achieved higher levels of engorgement if they fed on Sundevall’s jirds than if they fed on Egyptian fruit bats. The fleas digested blood of fruit bats and jirds significantly faster than blood of Kuhl’s pipistrelle. In addition, after a single blood meal, the survival time of fleas fed on normothermic Kuhl’s pipistrelles was significantly shorter than that of fleas fed on Sundevall’s jirds and even lower when male fleas fed on Egyptian fruit bats. Thus, our prediction was partially supported: normothermic Kuhl’s pipistrelles were inferior hosts for fleas compared with Sandevall’s jirds and Egyptian fruit bats. Interestingly, the proportion of engorged fleas that fed on torpid Kuhl’s pipistrelles was significantly higher than the proportion of the fleas that fed on normothermic individuals, indicating that becoming torpid might be a liability, rather than an effective defense against parasites.