Gastrointestinal Nematode Infection In Goats Research Articles

Gastrointestinal nematode infections in goats: differences between strongyle faecal egg counts and specific antibody responses to Teladorsagia circumcincta in Nera di Verzasca and Alpine goats.

Strongylida are gastrointestinal nematodes (GIN) of greatest importance in small ruminants throughout the world. Differences in resistance and resilience to GIN among goat breeds were reported. This study aims to investigate the mechanism underlying the breed-associated differences using a cosmopolitan (Alpine, AB) and an autochthonous (Nera di Verzasca, NV) goat breed. At first, fifteen goats from the same herd (NV = 7, AB = 8) at day 0 were infected with infective larvae (L3) of mixed GIN. From the 15th day post-infection (DPI), individual parasite egg excretion (faecal egg counts, FEC) was performed on all goats, once per week, until the 63rd DPI. Afterwards, in goats under field conditions (30 AB and 30 NV reared on the same farm), individual faecal and blood samples were collected; FEC-specific antibody and PCV levels were explored. In goats with experimental GIN infection, mean eggs per gram of faeces (EPG) values were consistently lower in NV goats. In goats with natural GIN infection, EPG and prevalence values showed high variability in both breeds; among individual variables, breed had a significant influence on EPG. Further, PCV and anti-T. circumcincta IgA levels were influenced by the breed. Lower PCV values were also associated with higher strongyle EPG in AB goats, and anti-T. circumcincta IgA levels were influenced by both strongyle EPG and breed, with IgA levels being higher in AB vs. NV goats and positively associated with EPG. Neither EPG nor breed had any influence on IgE levels. Both studies on experimental and natural infection confirmed that goats of NV are more resistant to infection with gastrointestinal nematodes.

Transcriptome variation in response to gastrointestinal nematode infection in goats.

Gastrointestinal nematodes (GIN) are a major constraint for small ruminant production. Due to the rise of anthelmintic resistance throughout the world, alternative control strategies are needed. The development of GIN resistance breeding programs is a promising strategy. However, a better understanding of the mechanisms underlying genetic resistance might lead to more effective breeding programmes. In this study, we compare transcriptome profiling of abomasal mucosa and lymph node tissues from non-infected, resistant and susceptible infected Creole goats using RNA-sequencing. A total of 24 kids, 12 susceptible and 12 GIN resistant based on the estimated breeding value, were infected twice with 10,000 L3 Haemonchus contortus. Physiological and parasitological parameters were monitored during infection. Seven weeks after the second infection, extreme kids (n = 6 resistant and 6 susceptible), chosen on the basis of the fecal egg counts (FEC), and 3 uninfected control animals were slaughtered. Susceptible kids had significantly higher FEC compared with resistant kids during the second infection with no differences in worm burden, male and female worm count or establishment rate. A higher number of differentially expressed genes (DEG) were identified in infected compared with non-infected animals in both abomasal mucosa (792 DEG) and lymph nodes (1726 DEG). There were fewer DEG in resistant versus susceptible groups (342 and 450 DEG, in abomasal mucosa and lymph nodes respectively). ‘Cell cycle’ and ‘cell death and survival’ were the main identified networks in mucosal tissue when comparing infected versus non-infected kids. Antigen processing and presentation of peptide antigen via major histocompatibility complex class I were in the top biological functions for the DEG identified in lymph nodes. The TGFβ1 gene was one of the top 5 upstream DEG in mucosal tissue. Our results are one of the fist investigating differences in the expression profile induced by GIN infection in goats.

Prevalence and risk factors associated with gastrointestinal nematode infection in goats raised in Baybay city, Leyte, Philippines.

Aim:Gastrointestinal parasitism is a serious constraint affecting goat production in the Philippines. This study aimed to determine the prevalence and associated risk factors of gastrointestinal nematode infection in goat-populated barangays of Baybay City, Leyte.Materials and Methods:A total of 81 households or farms were interviewed, and 450 goats were sampled for fecalysis. Fecal egg count along with egg morphological identification and coproculture for third stage larvae identification were conducted. Descriptive statistics and logistic regression analyses were carried out to determine the farm- and animal-level prevalence and risk factors.Results:Fecalysis revealed the presence of strongyle and Trichuris spp. with a farm-level prevalence of 100% and 4.94%, respectively; and animal-level prevalence of 96.22% and 4.44%, respectively. The identified strongyle genera per barangay were Haemonchus spp. (34.79%), Trichostrongylus spp. (33.29%), Oesophagostomum spp. (24.21%), Cooperia spp. (6.93%), and Chabertia spp. (0.79%). Goats older than 12 months were four times more likely to present high strongyle burden when compared to goats <6 months. With each month increase in goat’s age, the odds of acquiring strongyle infection also increased by 1.07 times. Animals kept in goat house with cemented flooring have lower odds of acquiring strongyle (odds ratio=0.12). Goats raised for leisure purposes and fed with carabao grass (Paspalum conjugatum) were 8.12 and 5.52 times more likely to acquire Trichuris, respectively.Conclusion:Most of the backyard goat raisers in Baybay City, Leyte, do not practice sound helminth control measures as shown by the high prevalence of gastrointestinal nematodes. The most relevant risk factors for gastrointestinal nematode infection were the age of the goat, type of goat house’s flooring, purpose of raising goats, and feeding practices.

Seasonal patterns of gastrointestinal nematode infection in goats on two Lithuanian farms.

BackgroundThis study investigated seasonal changes in naturally acquired gastrointestinal nematode (GIN) infections on two Lithuanian goat farms with different parasite control practices.FindingsOn both farms, nematode faecal egg counts (FEC) and larval cultures were obtained from 15 adult and 10 young goats at bi-weekly intervals from April 2012 to April 2013. Goats on farm A were dewormed with ivermectin (0.3 mg/kg body weight) in October/November 2012, whereas the animals on farm B were left untreated. Thirteen young goats were slaughtered in August/November 2012 and April 2013 and worm burdens in the gastrointestinal tract were enumerated. In goats from both farms, Teladorsagia, Trichostrongylus, Oesophagostomum, Chabertia and Haemonchus were the dominant GIN genera. Herbage contamination with infective third-stage larvae (L3) peaked in July/August and resulted in high FEC in September/October. Parasitological examination at slaughter showed that Teladorsagia spp. and Haemonchus contortus survived the winter, both in the abomasal mucosa as adults and as early fourth-stage larvae (EL4). Deworming on farm A significantly reduced FEC, especially of H. contortus, at the start of the grazing period compared with the untreated farm B (P < 0.05).ConclusionsGoats were heavily infected with several GIN throughout the year. Strategic anthelmintic treatment during housing significantly reduced nematode egg output, in particular by H. contortus, at the start of the grazing season.

Single nucleotide polymorphisms in candidate genes associated with gastrointestinal nematode infection in goats.

Cytokines are small cell-signaling proteins that play an important role in the immune system, participating in intracellular communication. Four candidate genes of the cytokine family (IL2, IL4, IL13, and IFNG) were selected to identify Single Nucleotide Polymorphisms (SNPs) that might be associated with resistance to gastrointestinal endoparasites in goats. A population of 229 goats, F2 offspring from an F1 intercross was produced by crossing pure Saanen goats, considered as susceptible to gastrointestinal endoparasites, with pure Anglo-Nubian goats, considered resistant. Blood was collected for DNA extraction and fecal samples were also collected for parasite egg count. Polymorphisms were prospected by sequencing animals with extreme phenotype for fecal egg count (FEC) distribution. The association between SNPs and phenotype was determined by using the Fisher exact test with correction for multiple tests. Three of the 10 SNPs were identified as significant (P ≤ 0.03). They were found in intron 1 of IL2 (ENSBTA00000020883), intron 3 of IL13 (ENSBTA00000015953) and exon 3 of IFNG (ENSBTA00000012529), suggesting an association between them and gastrointestinal endoparasite resistance. Further studies will help describe the effects of these markers accurately before implementing them in marker assisted selection. This study is the pioneer in describing such associations in goats.

The influence of stocking rate and mixed grazing of Angora goats and Merino sheep on animal and pasture production in southern Australia. 4. Gastrointestinal parasitism

Gastrointestinal nematodes limit the growth, production and welfare of goats but there are few reliable sources of information for recommending management practices across flocks. The effects of animal species (Angora goat, Merino sheep, mixed-grazed goats and mixed-grazed sheep at the ratio of 1 : 1) and stocking rate (SR: 7.5, 10, 12.5 animals/ha) on gastrointestinal parasitism were determined in a replicated experiment on improved annual temperate pastures in southern Australia, from 1981 to 1984. Detailed monitoring of gastrointestinal nematodes was undertaken on animals before, during (five times per year) and at the conclusion of studies using faecal strongyle egg counts (WEC) and total worm counts. Sheep had a greater proportion of nematodes as Teladorsagia spp. and goats a greater incidence of Trichostrongylus spp. Both goats and sheep developed resistance to Nematodirus spp. during the experiment. WEC was similar in goats and sheep at the start of the experimental period but, thereafter, was consistently greater in goats than in sheep. While WEC was highly related to total worm count, the regressions for sheep and goats were different. Increasing the SR increased the WEC of goats and mixed-grazed goats but not of sheep. During the experiment, WEC declined at 7 and 10 animals/ha but increased at 12.5/ha. Mixed grazing with goats provided beneficial effects for sheep at all stocking rates, but the effects for goats were dependent on the stocking rate, being beneficial at 7.5 and 10/ha but harmful at 12.5/ha. The WEC of separately grazed goats were generally higher than the WEC of mixed grazed goats. The WEC of mixed sheep were lower than those of separately grazed sheep. During the experiment, the WEC of mixed grazed sheep declined faster than the WEC of separately grazed sheep but the WEC of separately grazed goats at 12.5/ha and of mixed grazed goats at 10 and 12.5/ha increased. Under the environmental and pastoral conditions examined, Angora wether goats should not be grazed at SR above those recommended for wether sheep. In the present study, the impact of gastrointestinal-nematode infections in goats was reduced at lower SR. Further, mixed grazing of Angora wether goats with wether sheep at or below the recommended SR resulted in reduced gastrointestinal parasitism for both sheep and goats, compared with monospecific grazing conditions. Goats did not represent a gastrointestinal-nematode hazard to sheep.

The Efficacy of Moxidectin Against Gastrointestinal Nematode Infections in Goats

The Efficacy of Moxidectin Against Gastrointestinal Nematode Infections in Goats

The effect of long-term feeding of fresh and ensiled cassava (Manihot esculenta) foliage on gastrointestinal nematode infections in goats

The benefit of long-term feeding of fresh or ensiled cassava foliage on gastrointestinal parasite in goats was evaluated. Eighteen male goats (15.15 +/- 2.83 kg and between 4-6 months) were randomly allocated into three treatments supplemented with 200 g of wheat bran head(-1) day(-1). All groups were fed ad-libitum on either grass (CO), fresh cassava (CaF) or ensiled cassava foliage (CaS). At the beginning of the trial, each goat was inoculated with 3000 L3 containing approximately 50% Haemonchus contortus. Individual LWt, FEC and PCV were measured at weekly intervals for 10 weeks. At the termination of the experiment all goats were slaughtered for worm recovery and enumeration. The goats in CaF and CaS had similar weight gains while those in CO lost weight (p < 0.05) through the trial. FEC in CaF and CaS were lower (p < 0.05) than CO during the patency of parasite infections, but there was no difference between CaF and CaS goats. PCV of all groups decreased from above 30% to around 25% at the end of the trial. The compositions of established worm burdens were mainly H. contortus (19-40%) and Trichostrongylus colubriformis (55-76%). TWB did not differ among the groups, however, CaS significantly reduced H. contortus burdens, as compared to CaF and CO (p < or = 0.005). Thus, ensiled cassava foliage reduced the H. contortus population while the fresh foliage only reduced worm fecundity.

Sericea lespedeza hay as a natural deworming agent against gastrointestinal nematode infection in goats

Infection with gastrointestinal nematodes (GIN), particularly Haemonchus contortus, is the biggest constraint to profitable goat production in the United States (US). Due to widespread prevalence of anthelmintic resistance in goat GIN, alternative, non-chemical control methodologies are needed to increase profitability of small ruminant industries. A study was designed to test the efficacy of a high condensed tannin (CT) legume, sericea lespedeza [SL, Lespedeza cuneata (Dum.-Cours. G. Don)] against GIN of goats fed in confinement. The goats were given a trickle infection of 500 H. contortus larvae/animal three times per week during the trial to simulate natural infection. Twenty Boer bucks (6–8 months old) were fed bermudagrass [BG, Cynodon dactylon (L.) Pers.] hay plus concentrate for 5 weeks in confinement and then 10 animals were switched to SL hay for an additional 7 weeks. Throughout the trial, feces and blood were collected weekly from individual animals to determine fecal egg count (FEC) and blood packed cell volume (PCV). Fecal cultures were made weekly from pooled samples to determine treatment effects on GIN larval development. All goats were slaughtered at the end of the trial, with adult worms in the abomasum and small intestine of each goat recovered, counted, and identified to species. Feeding SL hay to goats significantly ( P < 0.01) reduced FEC and increased PCV compared with BG hay. In addition, a lower percentage of ova in feces from SL-fed goats developed into infective (L3) larvae. There was a direct effect of SL hay on adult worms, with significantly ( P < 0.01) lower numbers of both abomasal ( H. contortus, Teladorsagia circumcincta) and small intestinal ( Trichostrongylus colubriformis) nematodes compared with goats fed BG hay. Feeding SL hay to goats is an effective means of controlling parasitic nematodes and may be a potential supplement/replacement for chemical anthelmintics.

Influence of age, grazing system, season and agroclimatic zone on the prevalence and intensity of gastrointestinal strongylosis in Ugandan goats

The influence of various factors on the level of strongyloid infection and worm-egg output of goats in Uganda was assessed. Faecal examination of 1661 goats was carried out in four different agroclimatic zones in Uganda between November 1996 and August 1997. Generally, grazing system, season and agroclimatic zone were the only factors found to have a significant ( P<0.001) influence on the intensity of gastrointestinal nematode infections in goats, but age did not. Age, grazing system, season and agroclimatic zone were found to have a significant ( P<0.001) influence on the level of risk of nematode infections. The results of this study indicate that epidemiological factors have significant influence on the level of risk of gastrointestinal nematode infections and on the worm-egg output in goats, under field conditions with very little helminth control practice in Uganda.

Comparison of nematode infections of the gastrointestinal tract in Angora and dairy goats in a rangeland environment: relations with the feeding behaviour

A study was conducted in order to examine the possible influence of feeding behaviour on differences in the diversity and the intensity of nematode infections of the gastrointestinal tract between two breeds of goats placed in the same rangeland environment. Within the same flock bred on rangeland conditions, 10 Saanen dairy goats and 14 Angora goats were surveyed for 5 months (from May to September) and parasitological and behavioural parameters were measured. The level of nematode infection was estimated by monthly measurements of faecal egg counts whereas the feeding behaviour was assessed every fortnight. During the whole survey, nematode egg excretion was repeatedly higher in the Angora goats compared to the Saanen ones and significant differences were observed in May and September. This difference in egg excretion was related to major difference in feeding behaviour between the two breeds. In contrast with the Saanen does, Angora goats did not show any browsing and resting activities at any date of observation. Hence, Angora goats can be considered mainly as grazers whereas Saanen goats exhibit feeding activities close to browsers. The relative influence of feeding behaviour and host immune response on the susceptibility to gastrointestinal nematode infection in goats is discussed.

Genetic resistance to gastro-intestinal nematode parasites in Galla and Small East African goats in the sub-humid tropics

AbstractA study was carried out from 1992 to 1996 to compare the resistance to naturally acquired gastro-intestinal (GI) nematode parasite infections (predominantly Haemonchus contortus) of Galla and Small East African goats in the sub-humid coastal region of Kenya. A total of 204 Galla and 349 Small East African (SEA) kids were born from five kiddings. These were the progeny of 18 Galla and 17 SEA bucks. Live weights (LWT), blood packed-cell volume (PCV) and faecal egg count (FEC) were recorded at 1- to 2-month intervals from birth to about 14 months of age. The SEA kids were more resistant to GI nematode parasites than Galla kids as shown by their significantly lower FEC (P&lt; 0·001) in the post-weaning period (8- to 14-month-old kids) and lower mortality from birth to 14 months of age (P&lt; 0·05). There was no significant (P&gt; 0·05) breed effect on PCV, but Galla kids were significantly heavier (P&lt; 0·001) at all measurement times between birth and 14 months of age. Heritability estimates for LWT, PCV and FEC at the different sampling times were characterized by high standard errors. Heritability estimates for records taken at 4·5 and 8 months of age from a repeated measures analysis were 0·18 (s.e.0·08) for PCV and 0·13 (s.e.0·07) for logarithm-transformed FEC. The phenotypic and genetic correlation estimates between PCV and LFEC were moderately to highly negative and averaged –0·36 and –0·53, respectively. The results are discussed in relation to the limited evidence for resistance to GI nematode infections in goats and compared with the much stronger evidence for resistance in sheep.

Periparturient rise in fecal egg counts associated with prolactin concentration increase in French Alpine dairy goats.

Previous data on periparturient relaxation of immunity during gastrointestinal nematode infection in goats are scarce and conflicting; one study carried out in fiber (Angora) goats showed a positive association of fecal egg counts with prolactin concentrations around parturition, whereas the two other available studies dealing with dairy goats, gave divergent results. The objectives of the study were thus to assess the occurrence of a periparturient rise in fecal egg counts in dairy goats and to examine a possible relationship between the level of milk production and the intensity of the periparturient rise. A total of 28 French Alpine grazing dairy goats naturally infected with Teladorsagia, Trichostrongylus, and Oesophagostomum were allocated into two groups according to their reproductive status; group 1 (n = 7) consisted of nonpregnant lactating animals in the 3rd month of lactation, whereas group 2 (n = 21) was composed of dry goats at 6 weeks before term. Fecal egg counts, pepsinogen and phosphate blood concentrations, blood eosinophil counts, and prolactin concentrations were individually monitored at weekly intervals for 12 weeks (from midwinter to early spring). The mean fecal egg counts were significantly higher in pregnant goats during the 2 weeks before (668 versus 242 eggs per gram of feces (epg), P < 0.05) and the 2 weeks after (962 versus 279 epg, P < 0.01) parturition as compared with nonpregnant lactating animals. No significant difference was seen in the composition of larval cultures between the two groups of animals, with Oesophagostomum infective larvae being found predominantly, particularly at the time of parturition. Pepsinogen and phosphate concentrations as well as blood eosinophil counts were similar between the two groups throughout the survey and indicated a moderate larval challenge. The mean prolactin concentration measured in pregnant goats was significantly higher (P < 0.01) at the time of parturition (298 versus 130 ng ml(-1)) and at 4 weeks after parturition (387 versus 193 ng ml(-1)) than that determined in nonpregnant animals. Furthermore, a significant correlation (rs = 0.30, df = 79; P < 0.01) between fecal egg counts and prolactin concentrations was recorded for the pregnant goats during the 4-weeks period around parturition.

Efficacy of ivermectin against induced gastrointestinal nematode infections in goats.

The efficacy of ivermectin (0.08 per cent w/v oral solution) at different dose levels was evaluated against induced infections of adult Haemonchus contortus (21 days old) and Trichostrongylus colubriformis (21 days old) and fourth stage larvae of Oesophagostomum columbianum (17 days old), Ostertagia circumcincta (five days old) and Strongyloides papillosus (five days old). Twenty-five Boergoats (mutton goats) were randomly allocated by bodyweight within each sex to an untreated control group and four ivermectin treatment groups; ivermectin was administered at either 25, 50, 100 or 200 micrograms/kg orally, once. The goats were killed and processed for worm recovery 25 to 27 days after treatment. At 25 micrograms/kg the efficacy of ivermectin varied from 43 per cent for adult T colubriformis to more than 99 per cent for fourth larval stage O columbianum. Ivermectin at 50 micrograms/kg or higher was 99 per cent or more effective against all induced parasite infections with the exception of ivermectin at 50 micrograms/kg against S papillosus (97 per cent). For all parasites there was a statistically significant (P less than 0.05) difference between the control group and the pooled treated groups. No adverse reactions to ivermectin treatment were observed in the goats.