Changes in liveweight gain, blood constituents and worm egg output in goats infected with a sheep-derived strain of Trichostrongylus colubriformis

Two groups of goats were dosed with 20,000 and 40,000 sheep-derived strain (SDS) larvae of Trichostrongylus colubriformis respectively. Over a period of 42 days, goats dosed with 40,000 larvae lost more weight than goats dosed with 20,000 larvae. Anaemia was not observed in infected goats, but total serum proteins, albumins and phosphorus fell with infection.     

Failure of young goats to acquire resistance to Haemonchus contortus

Two experiments were carried out to investigate the acquisition by goats of resistance to Haemonchus contortus. In Experiment 1, five Saanen wethers reared worm-free and averaging 5 1/2 months of age at the start of the experiment, were dosed with 200 H. contortus infective larvae three times per week for 10 weeks (approximately 23 infective larvae/kg mean initial liveweight/week) and then given anthelmintic treatment. Each goat and an equal number of worm-free controls were then challenged with 10,000 infective larvae. Post mortem worm counts were carried out 30 days later. In Experiment 2, eight worm-free Saanen wethers, 14 months old at the start of the experiment, were dosed with 825 infective larvae per week for 14 weeks (approximately 23 infective larvae/kg mean initial liveweight/week) except for one week when only 300 larvae were given and one week when no larvae were given. After anthelmintic treatment, each received, together with seven worm-free control animals, a challenge dose of 15,000 infective larvae. Post-mortem worm counts were carried out 28 days later. There were no significant differences in post-mortem worm counts between previously infected and uninfected groups in either experiment. In both experiments, serum pepsinogen values rose significantly as a result of infection but there was no significant (p>0.5) correlation between worm counts and pepsinogen values on the day of slaughter.     

Failure of young goats to acquire resistance to Haemonchus contortus

Two experiments were carried out to investigate the acquisition by goats of resistance to Haemonchus contortus. In Experiment 1, five Saanen wethers reared worm-free and averaging 51/2 months of age at the start of the experiment, were dosed with 200 H. contortus infective larvae three times per week for 10 weeks (approximately 23 infective larvae/kg mean initial liveweight/week) and then given anthelmintic treatment. Each goat and an equal number of worm-free controls were then challenged with 10,000 infective larvae. Post mortem worm counts were carried out 30 days later. In Experiment 2, eight worm-free Saanen wethers, 14 months old at the start of the experiment, were dosed with 825 infective larvae per week for 14 weeks (approximately 23 infective larvae/kg mean initial liveweight/week) except for one week when only 300 larvae were given and one week when no larvae were given. After anthelmintic treatment, each received, together with seven worm-free control animals, a challenge dose of 15,000 infective larvae. Post-mortem worm counts were carried out 28 days later. There were no significant dii- ferences in post-mortem worm counts between previously infected and uninfected groups in either experiment. In both experiments, serum pepsinogen values rose significantly as a result of infection but there was no significant (p>0.5) correlation between worm counts and pepsinogen values on the day of slaughter.     

Parasites of domestic and wild animals in South Africa. XII. Artificial transmission of nematodes from blesbok and impala to sheep, goats and cattle.

Sheep were successfully infested artificially with the larvae of Haemonchus contortus, Trichostrongylus axei, Trichostrongylus falculatus and Impalaja nudicollis, cultured from the faeces of blesbok naturally infested with these nematodes. Haemonchus placei, Longistrongylus sabie, Trichostrongylus colubrifomis, T. falculatus, Impalaia tuberculata and Cooperia hungi likewise became established in sheep, goats and calves dosed with larvae cultured from the faeces of infested impala. Sheep and goats could also be infested with Cooperioides hamiltoni and Oesophagostomum columbianum of impala origin, but Cooperioides hepaticae could not be transmitted either to these hosts or to calves.     

Influence of an experimental infection of Strongyloides ransomi on performance of pigs

Sixty-four pigs (average 21.8 kg live weight) were divided into 16 comparable groups of four, each based on sex and body weight, to study the effects of a single infection of Strongyloides ransomi (either 0, 5,000, 10,000 or 20,000 S. ransomi larvae/kg body weight) on performance during a 91-d trial. Final weight, weight gain and average daily gain of pigs not infected were greater (P less than .01) than those of pigs given either 5,000 or 10,000 S. ransomi larvae/kg body weight, which in turn were greater (P less than .01) than those of pigs given 20,000 S. ransomi larvae/kg body weight. Average daily gain for pigs not infected was 40% greater (P less than .01) than that of pigs given 20,000 S. ransomi larvae/kg body weight. Feed required per unit of weight gain was 44% greater for pigs given 20,000 S. ransomi larvae/kg body weight than for pigs not infected, but this difference was not significantly greater due to extreme variation within the group of infected pigs. In each of two trials, eight crossbred barrows (average 20.0 kg in trial 1 and 22.7 kg body weight in trial 2) were examined for the effects of two levels of S. ransomi infections (0 and 10,000 larvae/kg body weight) on digestion and absorption of nutrients and on N balance. Digestion coefficients for dry matter, crude protein and gross energy for pigs not infected were greater (P less than .05) than for those experimentally infected.(ABSTRACT TRUNCATED AT 250 WORDS)     

Development of resistance to Trichostrongylus colubriformis in goats

A high level of host resistance to Trichostrongylus colubriformis was established in a group of Saanen goats infected weekly with 10,000 infective larvae for 10 weeks, treated with an anthelmintic and then challenged twice with 50,000 larvae, with a further anthelmintic treatment 28 days after the first challenge. A second group of goats exposed only to the two challenge infections developed worm burdens intermediate between, and significantly different from, the first group and a third control group given only the second challenge infection. Nematode fecundity (eggs per female) and male:female ratios were also significantly decreased in the first two groups. Faecal egg counts and worm counts were highly correlated and this relationship was dominated by the influence of the number of eggs/female nematode. The goats were approximately 9 months old at the start of the experiment.     

Efficacy of the nematode-trapping fungus Duddingtonia flagrans against three species of gastro-intestinal nematodes in laboratory faecal cultures from sheep and goats

The ability of the nematode-killing fungus Duddingtonia flagrans to reduce number of infective larvae of three species of gastro-intestinal parasitic nematodes developing in dung was investigated in both goats and sheep. Groups of lambs and kids (12-20 weeks old) were given mono-specific infections of Haemonchus contortus, Ostertagia (Teladorsagia) circumcincta or Trichostrongylus colubriformis. Following patency of the infections (t1) faecal samples were collected for determination of faecal nematode egg count (FEC) and culture of parasite larvae. Groups of animals were then dosed on 2 consecutive days with one of the two dose rates of the fungus (250,000 or 500,000 spores/kg liveweight). One (t2) and 5 (t3) days after the second dose of fungus samples were again collected for FEC and culture. The number of larvae recovered from the faecal cultures at t1 and t3 were used as controls to assess the efficacy of the experimental treatment at t2. Average efficacy was 78% with group means ranging from 40 to 93%. Dose rate of fungus appeared to influence efficacy against O. circumcincta but not against H. contortus or T. colubriformis. Overall, there were no differences in the efficacy of the fungus against any of the parasite species or in either host animal. The results of this trial indicate the potential use of this fungus as a broad spectrum anti-parasite agent for use in both goats and sheep.     

Parasites as stressors: plasma cortisol responses of goats infected with the stomach worm Haemonchus contortus to exogenous corticotropin (ACTH)

Ten male, juvenile pigmy goats of similar age and weight were allocated randomly to two groups. Goats in one group were each inoculated with 20,000 infective larvae of Haemonchus contortus. The other group served as uninfected controls. Goats were housed together, and precautions were taken to avoid the creation of differential, between group, stressogenic circumstances. Body weights, nematode egg production, hematocrits, and clinical signs were monitored over a 61-day period following inoculation of larvae. On Days 59 and 61, adrenal response tests (ART) were conducted by measuring the levels of plasma cortisol before and 2 h after administration of porcine ACTH at the rate of 0.35 I.U. kg-1 body weight on Day 59 and 2.2 I.U. kg-1 on Day 61. Although the infections did not reduce body weights, they were 'heavy' on the basis of egg production, and led to significant reductions in packed erythrocyte volumes. There was no significant difference between the groups of goats in the responses to ART, indicating that the infections did not produce sufficient stress to reduce the ability of the adrenal cortex to respond to exogenous ACTH.     

Efficacy of fenbendazole and cambendazole against Muellerius capillaris in dairy goats

Two anthelmintics, fenbendazole and cambendazole, were used in an attempt to eliminate Muellerius capillaris infections in a group of 44 goats. During the course of this study (508 days), M capillaris larvae were found in at least one fecal specimen from each of 22 of the 44 goats. All 44 goats were dewormed with fenbendazole (30 mg/kg of body weight) at the onset of this study (day 18). Two additional dewormings with fenbendazole at 4- to 8-week intervals were restricted to the goats that continued to shed M capillaris larvae. On the basis of routine fecal examinations, fenbendazole eliminated M capillaris larvae from the feces of 8 (36%) of these 22 goats. On day 253, cambendazole (60 mg/kg) was given orally to 17 of these 22 goats (2 of the 22 had died and 3 were not available for treatment); 13 of these goats were still shedding M capillaris larvae. Cambendazole eliminated M capillaris larvae from the feces of 10 (77%) of these 13 goats chronically infected with M capillaris.     

Goats and sheep as hosts for some common cattle trichostrongylids

Recently weaned kid goats, lambs and calves, raised under worm-free conditions, were dosed with infective larvae of Ostertagia spp. and Cooperia spp. derived from naturally infected cattle. Each animal received a similar mixed dose of 60 000 infective larvae. Postmortem examination four weeks after infection revealed that the overall establishment of Ostertagia spp. in the kids was markedly less than in either the calves or the lambs, while the establishment in the lambs was marginally less than in the calves. Species composition of the Ostertagia burdens at necropsy differed widely between the host species. In the calves, O. ostertagi was the dominant species (57.8–73.4%), whereas in the lambs it was less successful (12.3–51.4%), and in the goats it was present in only very small numbers (0.0–3.8%). The proportion of O. crimensis present in the Ostertagia burden of each of the lost species was inversely related to the level of O. ostertagi present. A similar level of establishment of Cooperia spp. occurred in both lambs and calves, but no Cooperia established in the goats.     

Parasites of domestic and wild animals in South Africa. XLVI. Oestrid fly larvae of sheep, goats, springbok and black wildebeest in the Eastern Cape Province

Merino sheep in Thornveld, Dorper sheep and Angora goats in inland Valley Bushveld, Angora goats and Boer goats in Valley Bushveld on the coastal plateau, and springbok, Antidorcas marsupialis, and black wildebeest, Connochaetes gnou, in Karroid Mountainveld, all in the Eastern Cape Province, were examined for the larvae of nasal bot flies. The sheep and goats were infested with the larvae of Oestrus ovis, and Dorper sheep and Boer goats harboured more larvae than Angora goats on the same farms. Most infestation was present from November to May in Merino sheep in Thornveld, from February to June in Dorper sheep in inland Valley Bushveld, and from May to September in Angora and Boer goats in Valley Bushveld on the coastal plateau. These patterns of seasonality appeared to be regulated by the severity of the summer temperatures at the various localities. The springbok were infested with the larvae of Rhinoestrus antidorcitis, most of which seemed to mature from June to August. All larval sages of Oestrus variolosus and Gedoelstia h?ssleri were present in the black wildebeest, and large numbers of 1st instar larvae of G. h?ssleri appeared to accumulate on the dura of the wildebeest from June to August.     

Facial eczema in goats: the toxicity of sporidesmin in goats and its pathology

Groups of six goats were orally dosed with sporidesmin at rates of 0.3, 0.6, 1.2 and 2.4 mg of sporidesmin per kg body weight and their responses up to 6 weeks later compared with those of sheep dosed at the same time. Clinical facial eczema and pathological lesions similar to those found in sheep were found in all the goat breeds, but at higher dose rates of sporidesmin than those which caused equivalent lesions in sheep. Saanens were the most susceptible goat breed, requiring 2-4 times as much sporidesmin as sheep to achieve similar effects. G4 and feral goats required 4-8 times the sheep dose of sporidesmin to obtain similar responses. Gamma-glutamyltransferase reached its highest serum levels after 20 days while glutamate dehydrogenase and aspartate aminotransferase reached their highest levels between 10 and 20 days. Alkaline phosphatase did not rise consistently to high levels in affected goats. The elevation in aspartate aminotransferase levels tended to be early and transient; glutamate dehydrogenase early and prolonged; gamma-glutamyltransferase late and prolonged, and'alkaline phosphatase late and minor. There was considerable individual variation in the time at which elevations occurred and the levels which enzymes reached. Cholesterol and bilirubin levels were high if liver injury was severe.     

Efficacy of doramectin against experimental infections by some nematode parasites in cattle in New Zealand

A study was undertaken to determine the efficacy of the novel avermectin, doramectin, against experimental larval and adult infections of three species of nematode parasite important to cattle production in New Zealand. Eighteen worm-free dairy bull beef calves were randomly allocated on live weight to three similar treatment groups. Each calf was given 30,000 Ostertagia ostertagi, 20,000 Cooperia spp. and 10,000 Trichostrongylus axei infective larvae as a single dose. One group was treated with doramectin 6 days after infection while the remaining groups received saline or doramectin 27 days after infection. Given as a single subcutaneous injection behind the ear, doramectin at 200 microg/kg removed 99.9-100% of adult and larval stages of O. ostertagi, Cooperia spp. and T. axei when compared to infections established in untreated controls (p<0.001). No adverse reactions were observed following treatment in the doramectin-treated animals. No injection site lesions were found by palpation following treatment or by injection site examination at necropsy.     

The establishment and development of Trichostrongylus colubriformis in goats

Twelve goats were inoculated with 20,000 infective larvae of Trichostrongylus colubriformis and two were killed on each of Days 4, 7, 11, 14, 18 and 21 after inoculation (DAI). The number of worms that established, and the site of development were recorded. Most of the worms established within the first 3 m of the small intestine. There was little relocation or loss of nematodes after establishment. The worms started to migrate from the mucosa to the lumen 11 days after infection. At 4 DAI, 63% of the worms were still at the late L3 stage; the remainder of the worm population had completed the third moult to the L4 stage. The population at 11 DAI comprised largely young adults. When 21 DAI was reached, about 57% of the female worms had eggs in their uteri.     

Przhevalskiana silenus myiasis among slaughter goats in northern Jordan

During the period December 1998-May 2000, 900 local goats slaughtered at the Irbid Abattoir (northern Jordan) were examined for the larval instars of Przhevalskiana silenus. Of 900 goats, 10% (95% CI: 9,13) were infested with P. silenus larvae. Only the second and third larval instars were seen. A multiple-regression analysis (with the error variance described by the negative-binomial function) suggested that infestation depended on the month of sampling, and that infestation with live larvae was associated with a poorer carcass. The percentage of infested goats and the mean monthly total number of larvae per goat peaked in samples taken in the autumn and winter. Larval numbers were highly aggregated: most animals had no larvae but the maximum was 69. Analysis of the pattern of aggregation suggested that the best model fit was one in which the larvae counts per goat varied with the monthly prevalence.     

Polymyxin B: pharmacokinetics of single doses given intravenously and intramuscularly to turkeys, and minimal inhibitory concentrations for Escherichia coli and Pasteurella multocida.

The 50% and 90% minimal inhibitory concentrations (MIC50 and MIC90) of polymyxin B for avian Escherichia coli and Pasteurella multocida isolates were determined by the agar plate dilution method. Polymyxin B at approximate MIC level in serum was bactericidal for E. coli in 2 to 4 hours. Aqueous polymyxin B sulfate was administered by a single bolus intravenous injection into turkeys at 10,000 IU/kg, and by a single bolus intramuscular injection at 5,000, 10,000 or 20,000 IU/kg. Effective serum drug concentrations after intramuscular injection (MIC50 levels or greater) were maintained for E. coli for 7.0 hr (10,000 IU/kg) and 11.5 hr (20,000 IU/kg), and for P. multocida for 3.0 hr (10,000 IU/kg) and 4.1 hr (20,000 IU/kg). Pharmacokinetic parameters were calculated by non-compartmental methods. Elimination time half-lives, mean residence time, clearance, and apparent volume of distribution at steady state (Vdss) were all much higher for i.m. injection of 20,000 IU/kg than for i.m. injection of 10,000 IU/kg. We postulate that there exists a minimal tissue-interaction threshold concentration (MTC) at which polymyxin B can enter previously unavailable compartments or bind to previously refractory tissue components. Bioavailability of polymyxin B injected i.m. was 0.904 for the 10,000 IU/kg dose and 0.675 for the 20,000 IU/kg dose. Dosage intervals necessary to produce minimal steady state concentrations (Cssmin) equal to the MIC were calculated. Certain aspects of the use of the parameter Vdss, and limitations on the use of dosage interval calculations for polymyxin B, are discussed. One week after i.m. injection of polymyxin B at 10,000 IU/kg, high tissue drug levels were present, especially in bound form in liver. Following single injections, no toxic effects on turkeys were observed.     

Parasitologic, clinical, hematologic and serologic findings in puppies after lactogenic infection with Ancylostoma caninum ERCOLANI 1859 (Ancylostomidae)]

The correlation between intensity of Ancylostoma caninum infections in bitches and the intensity of lactogenic infections and clinical signs of their puppies was investigated. On average, 825, 1,867 or 2,125 specimens were observed in litters of two bitches inoculated with 5,000, 10,000 or 20,000 third stage larvae (LIII) respectively, at the day of conception. Adverse effects of the infection on the growth and behaviour of the puppies were observed after onset of their second week of life: 11/27 puppies died during the fourth week. The body weight of puppies surviving 28 days was up to 750 g less than that of uninfected controls. Eosinophilia, erythroblastosis and microcytic, hypochromic anemia developed in all puppies during their first four weeks. The IFA test (LIII antigen) was positive for only 5/18 heavily infected puppies after uptake of colostrum.     

Effect of copper oxide wire particle treatment on establishment of major gastrointestinal nematodes in lambs

Eighty-four 10-week-old lambs were used to investigate the effect of copper oxide wire particle treatment on the establishment of major gastrointestinal nematodes. They were maintained on pasture previously treated to minimise larval contamination. Five grams of uniform sized copper oxide wire particles were given orally five days before infection with either 20,000 Trichostrongylus colubriformis larvae, 20,000 Ostertagia circumcincta larvae or 3000 Haemonchus contortus larvae given as three doses at three-day intervals. The animals were slaughtered 21 or 22 days after the last infective dose. Parasite burdens in the lambs treated with copper oxide wire particles were reduced by 96 per cent in the case of H contortus and by 56 per cent in the case of O circumcincta compared to burdens in controls. There was no significant effect of copper particles on the establishment of T colubriformis.     

Ixodid ticks on ruminants, with on-host initiated moulting (apolysis) of Ixodes, Haemaphysalis and Dermacentor larvae

To screen the host-dependent abundance of hard tick (Acari: Ixodidae) developmental stages on ruminants in South Hungary, red and roe deer, as well as goats and sheep were examined in a season, when larvae and nymphs are active. Altogether 2271 ticks were collected. In the relevant period the prevalence of tick-infestation was significantly higher among goats, than among sheep kept in the very same area, most likely in association with the browsing habit of the former. Roe deer and goats were found to be important hosts for Ixodes ricinus and Haemaphysalis concinna larvae, in contrast to the view that this stage does not usually feed on medium-sized mammals. Interestingly, one third of I. ricinus larvae and one larva of H. concinna and of Dermacentor reticulatus collected from goats in the same herd in August have started the moulting process (showed apolysis) on their host, despite being three-host ticks. This is the first survey involving four species of domestic and wild ruminants in Europe to compare the host-preference of ixodid ticks in the same region.     

Effects of Daily Oral Administration of Copper to Goats

Three goats were dosed orally with a 0.2 % aqueous copper sulphate solution. The dosing was 20 mg copper sulphate/kg body weight twice a day for 56 to 113 days. One of the goats accumulated substantial amounts of copper in the liver and developed two haemolytic crises. The two other goats showed only increased liver copper concentrations before they were killed. The results indicate that the goats were susceptible in varying degrees to repeated oral copper dosing, and that two of the goats were significantly less susceptible to copper than sheep. The goat that turned into a haemolytic crisis showed changes similar to those seen in sheep as far as blood and plasma parameters are concerned. The gross and histological lesions were also mainly of the same type as described in sheep. The hepatic lesions found in the goat differed to some degree from those found in sheep as the necroses were more distinctly located to the centrilobular area, and as the iron pigments were mainly located in phagocytes in the hepatic sinusóides.