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1.
The efficacy of oxfendazole was tested in naturally infected Sokoto-Gudali calves at a dosage of 2.8 mg per kg. At this dosage level, oxfendazole showed 100 per cent efficacy against adult and immature forms of Haemonchus spp, Trichostrongylus spp, Bunostomum phlebotomum and Oesophagostomum radiatum. Although efficacy of 100 per cent was recorded for the adult form of Cooperia spp, only 48 per cent reduction was recorded for its immature stages. Similarly, a percentage reduction of 75 was recorded for adult Trichuris spp. No larvae hatched out of a seven-day vermiculite culture of faeces collected from the treated calves 24 h after treatment.  相似文献   

2.
The efficacy, safety, and compatibility of fenbendazole (FBZ) and clorsulon (CLN) were tested after oral administration of label recommended and of higher (5x) dosage rates to calves naturally infected with gastrointestinal nematodes and Fasciola hepatica. Results for 42 calves allotted to 4 treatment groups indicated a similar efficacy against mature F hepatica by FBZ (5 mg/kg of body weight) and CLN (7 mg/kg) in a combined oral suspension, compared with CLN (7 mg/kg) alone (100 vs 99% reduction). A lesser efficacy was observed against immature flukes (88.6 and 84.9% reduction, respectively). Calves given 25 mg of FBZ/kg and 35 mg of CLN/kg had nearly complete reduction of both mature (99.6%) and immature flukes (99.1%). Fasciola egg counts were reduced by greater than 99.5% in all treated groups. Against Ostertagia ostertagi, the percentage of efficacy of the combined FBZ (5 mg/kg) and CLN (7 mg/kg) treatment was 94.3% against adults and 81.3% against inhibited larvae. Efficacy against all other nematodes was 100%, except against Cooperia spp adults (98.3%) and immature Oesaphagostomum radiatum (88.0%). At 5 x dosage rates for FBZ and CLN, percentage of removal of adults and inhibited larvae of O ostertagi was 99.3 and 99.0%, respectively, and 99 to 100% for other nematodes. Results indicate that FBZ and CLN are compatible when mixed together and administered as an oral suspension to cattle and that the efficacy is similar to that of the drugs individually. On the basis of further results, we suggest that summer treatment may be superior in preventive value for gastrointestinal nematodes and F hepatica, compared with spring treatment, because of seasonal infection dynamics of the major cattle parasites in Louisiana.  相似文献   

3.
Treatment of buffalo calves (Bubalus bubalis) at different times after birth demonstrated that transmission of Toxocara vitulorum from the cow to the calf via milk occurs in all calves during the first 2 days after birth, decreases to 53% by 6 days, 10% by 8-9 days and 2% from Day 10 onwards. This may be because the larvae are no longer in the milk or because the calf has become resistant to the establishment of a new infection. The result also emphasizes the importance of mammary transmission of the parasite. Against immature parasites the efficacy of pyrantel and levamisole was 97%; febantel was 100% on one farm, only 35% on another; piperazine 42% and thiabendazole 35%. Santonin was ineffective in four calves. Against mature parasites the efficacy of pyrantel was 100%; febantel was 100% on one farm, only 35% on another; oral levamisole 83%; cutaneous levamisole 73%; oxfendazole 89%; and piperazine 57%. Nevertheless, piperazine reduced the infection to levels which were probably not pathogenic. In general, the efficacy against mature parasites was similar to that against immature parasites. Treatment of 10-16-day-old calves with an anthelmintic, which is effective against immature parasites, is recommended. This procedure greatly reduces contamination of the environment and also precludes the pathogenic effect of a large number of immature or mature parasites.  相似文献   

4.
Activity of the feed premix formulation (M-1839) of crufomate against helminths of the gastrointestinal tract and lungs of cattle was determined in a controlled test. Eight calves were treated and 7 were nontreated. The dosage rate of crufomate was 17 mg of active drug/kg of body weight daily for 3 consecutive days. Removal activity was high against mature Cooperia oncophora (99%) and C punctata (96%) and immature Cooperia spp (87%). Removal of mature Ostertagia ostertagi was 68%. The removal of strongyloides papillosus and Bunostomum phlebotomum was 72% and 67%, respectively, but only a few specimens were present in the nontreated calves. Efficacies against the other mature and immature species of nematodes ranged from 0% to 34%. Lungworms (Dictyocaulus viviparus) were not effectively removed.  相似文献   

5.
The efficacy of febantel at a dosage of 5 mg/kg (45.5% paste formulation) against inhibited early 4th-stage larvae (EL4) of Ostertagia ostertagi, other nematodes of the abomasum, and Dictyocaulus viviparus was investigated in 4- to 6-month-old Holstein calves that grazed on pasture heavily contaminated with parasites from February 24 to April 1, 1986 (36 days). In Louisiana, this is the first month of a 3-month period in which increasing numbers of inhibition-prone O ostertagi larvae are acquired, and infection risk with D viviparus may remain high. Three of 4 calves that died of lungworm infection during the pasture-exposure period were necropsied. Large numbers of abomasal nematodes, including inhibited O ostertagi larvae, and large numbers of D viviparus were recovered. Twenty-five calves were randomly allotted by equal distribution of body weight to 2 groups and treated on April 4: placebo-treated calves (n = 13) and febantel-treated calves (n = 12). Equal numbers of treated and control calves were killed at 6 and 7 days, respectively, after treatment. Mean numbers of O ostertagi in control cattle were: adults, 4,931; developing 4th-stage larvae (DL4), 1,119; and inhibited EL4, 3,410. Ostertagia lyrata, Trichostrongylus axei, Haemonchus sp, and D viviparus were well distributed in nearly all control calves. Percentage reduction of O ostertagi in treated calves, when compared with controls, was: adults, 83.6%; DL4, 57.8%; and inhibited EL4, 34.8%. Percentage reductions of other species were: O lyrata, 92.6%; T axei adults, 99.3% and 4th-stage larvae (L4), 100%; Haemonchus sp adults, 66.7%, and L4, 64%; D viviparus adults 90.6%, and immature forms, 97.1%.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

6.
Treatment of bovine calves 10-16 days old with an anthelmintic which is effective against immature Toxocara vitulorum killed the parasites, there was no new infection and recontamination of the environment was precluded. When the management of the program was delegated to the livestock officers, approximately 3% of calves scheduled for treatment developed patent infections. The prevalences of toxocarosis on the different farms were correlated with annual rainfall, probably because the longer dry periods associated with lower rainfall killed infective eggs in the environment. The treatment schedules prevailing before the study commenced were ineffective. The prevalence of toxocarosis in the bovine calves on farms in the area with an annual rainfall of about 1000 mm was lower than that in buffalo calves studied previously in the same area.  相似文献   

7.
A series of trials to establish the anthelmintic efficiency of levamisole, when applied dermally to calves, is described. The levamisole base was formulated in a suitable solvent system at 100 g/l and applied dermally at a dose rate of 8 mg base/kg. This gave efficiencies of 97.1-100%, 88.5-100%, 100%, 98.7-100% and 89.2-100% against adult Haemonchus placei, Ostertagia spp, Cooperia spp, Oesophagostomum radiatum and Trichostrongylus axei, respectively. Activity against the immature stages of H. placei was recorded at 100%, and against immature Cooperia spp the range was 96.3-100%. Extremely variable results were obtained against immature Ostertagia spp, efficiency ranging from 0% to 100%. Efficiency against adult Dictyocaulus viviparus was in the range of 84-100%. The potential advantage of a dermally applied anthelmintic is discussed.  相似文献   

8.
The toxicity of zinc ethylene-bis-dithiocarbamate (zineb), a widely used fungicide, was studied in four 4-week-old Friesian calves with immature rumen function. Calves were first subjected to liver biopsy, and thereafter, 3 of them were orally administered 200 mg of zineb/kg of body weight daily for 80 days, whereas the fourth calf served as control and remained untreated. Clinical, hematologic, and pathologic (including ultrastructural) findings were recorded. The distribution in body fluids and tissues of the parent compound and one of its main metabolites, ethylenethiourea (ETU), also was examined. Treated calves had unthrifty appearance and reduction in weight gain. They also had remarkable impairment of thyroid function, as reflected by reduction in serum concentrations of triiodothyronine and thyroxine and increase in weight of the thyroid gland associated with epithelial vacuolization and foci of hyperplasia. Moderate increase in liver glycogen content and impairment in maturation of germ cells were recorded consistently. Whereas zineb was widely distributed in body tissues, ETU accumulated mainly in the liver and the thyroid gland, although noticeable concentrations also were attained in muscle. Data were consistent with involvement of ETU mainly in the pathogenesis of thyroid gland lesions, and indicate that unweaned calves given zineb develop a clinicopathologic syndrome that does not differ qualitatively from that already described in adult cattle exposed to zineb.  相似文献   

9.
Controlled tests were used to assess the efficacy of anthelmintics against immature paramphistomes, predominantly Calicophoron calicophorum, in 127 calves which were exposed to contaminated pasture for 7 weeks, treated and slaughtered. When a combination product of oxyclozanide and levamisole was used, oxyclozanide at 18.7 mg/kg reduced parasite numbers in the small intestine, abomasum and rumen-reticulum by 61 to 96.1%, 50.0 to 92.6% and 56.5 to 98.1%, respectively. When 2 doses were given 3 days apart, oxyclozanide was 99.9%, 100% and 100% effective, respectively, in the above organs, and produced improvement in clinically affected calves. This treatment elicited transient diarrhoea. Hexachlorophene at 20 mg/kg as a single dose was 99.5%, 100% and 100% effective against the fluke in the small intestine, abomasum and rumen respectively but severe neurological signs were seen in some calves. Niclosamide at 160 mg/kg given as single or 2 doses 3 days apart was 91.1% and 92.6% effective, respectively, against the parasites in the small intestine. No toxicity was noted. Closantel, at 7.5 mg/kg was not effective. Oxyclozanide and niclosamide when given as a single treatment had varying activity. Two doses of oxyclozanide and a single dose of hexachlorophene gave consistent results. Further tests based on reduction of faecal egg counts, 10 to 14 days after treatment were conducted with oxyclozanide and hexachlorophene against mature paramphistomes in 207 cattle. Oxyclozanide as a single dose or 2 doses 3 days apart at 12.8 to 18.7 mg/kg was 93.6 to 97.5% effective in reducing egg counts. Hexachlorophene at 20 mg/kg was 83.0% effective.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

10.
Two controlled tests were conducted in 1981 and 1982 in dairy calves on the University of Kentucky research farm to determine activity of the bolus formulation of levamisole given at the dose rate of 8 mg/kg against naturally occurring infections of Ostertagia ostertagi. Removal efficacies of mature O ostertagi were 98% in the 1981 test (3 treated and 3 nontreated calves) and 94% in the 1982 test (7 treated and 8 nontreated calves). Against immature Ostertagia spp, removal efficacies were 100% and 65% for the 1st and 2nd tests, respectively. The calves were grazed on the same pasture as dairy calves in previous controlled tests in 1979 and 1980 where activity of levamisole against mature O ostertagi (data recently published) was much less than in the present tests. It does not appear that the poor performance in the early tests can be attributed to the drug resistance phenomenon. Data on overwinter survival (119 days) of free-living stages of gastrointestinal parasites on pasture were derived from the nontreated calves in the 1982 controlled test. The calves, raised helminth-free, were placed on the pasture on Apr 5, 1982. Helminths recovered at necropsy of the calves, besides O ostertagi, included Trichostrongylus axei, Nematodirus helvetianus, Nematodirus spp, Cooperia oncophora, Trichuris spp, and Moniezia spp. The lung-worm, Dictyocaulus viviparus, previously found in cattle on the farm, was not found in these calves.  相似文献   

11.
The immunisation of young milk-fed calves with two doses of the commercially available Dictyocaulus viviparus irradiated larval vaccine, Dictol, was studied. In the first experiment, vaccination of groups of pail-milk-fed calves at 3 and 7 weeks of age resulted in 96.7% reduction of lungworm burdens upon challenge when compared with non-vaccinated controls. Contemporaneous vaccination of calves aged 8 and 12 weeks resulted in a reduction in lungworm burden of 98.9% compared with controls of the same age. The clinical reaction upon challenge of both age groups was minimal compared with their respective controls.In the second experiment a group of six suckling calves were vaccinated with Dictol at 3 and 7 weeks of age and then challenged with infective larvae of D. viviparus together with non-vaccinated controls. At subsequent post-mortem examination the mean lungworm burdens of the vaccinates was 87% less than that of the controls. Some clinical reaction evidence by increased respiratory rates and bodyweight loss occurred in the vaccinates but this was not as severe as in the controls. At necropsy a concurrent pneumonia due to Mycoplasma spp. was present and it is suggested that this contributed to the poorer protection obtained compared with the pail-milk-fed calves of the fist experiment.In the third experiment a group of suckling calves were again vaccinated at 3 and 7 weeks of age and then exposed to a natural challenge together with parasite-naive controls. Although the level of challenge was relatively low, immunisation was apparently high successful as lungworms were completely absent in the vaccinates when examined at necropsy.In all three experiments numerous pulmonary lymphoid nodules, which are a useful guide to the immune status of calves, were present in the vaccinates and absent or scarce in the controls. It is concluded that the cumulative evidence from the three experiments suggest that immunisation against infections of D. viviparus of young milk-fed calves in the field may be a practical proposition.  相似文献   

12.
Summary The activity of albendazole against gastrointestinal helminths in naturally infected calves in the Netherlands was tested. The calves were in their fist grazing season and kept in two groups of ten. One of these groups was grazed alternately with sheep. Five out of each group were drenched with albendazole (7.5 mg/kg) on the day they were housed (November 1). Before and 2, 14, and 28 days after treatment individual faecal samples were taken from all calves and larval cultures were made. Ten calves, six treated and four untreated, were killed for post mortem studies 14 days after treatment The remaining calves were slaughtered 14 days later. The drug was highly effective in reducing the egg output, measured as the number of larvae cultured per gram of faeces. Compared with the untreated calves, the reduction was more than 99% two days after treatment, 100% at 14 days, and 99% after 28 days. It was shown that egg output 28 days after treatment came from worms which had developed from arrested larvae of Ostertagia ostertagi that had survived treatment. Post mortem results showed an efficacy of 100% against adult O. ostertagi, of almost 100% against Trichostrongylus axei, and 100% against adult and larval Cooperia oncophora. Twenty-eight days after treatment, the reduction of arrested early fourth stages of O. ostertagi was 85% in comparison with the untreated calves. Apparently less effect was found against Trichuris ovis at the given dose rate.  相似文献   

13.
Anthelmintic efficacy of ivermectin (greater than or equal to 80% 22,23-dihydroavermectin B1a and less than or equal to 20% 22,23-dihydroavermectin B1b) was evaluated in a controlled experiment against immature nematodes. Twenty calves raised to about 8 weeks of age under nematode-free conditions were allocated into 4 groups. Infective larvae of Haemonchus contortus, Ostertagia ostertagi, Trichostrongylus axei, T colubriformis, Cooperia oncophora, C punctata, Oesophagostomum radiatum, and Dictyocaulus viviparus were given orally to each calf on a staggered schedule 6 to 14 days before treatments. The drug was given subcutaneously when the nematodes were in the early 4th stage of development, and the calves were killed 23 or 24 days later. Group 1 nonmedicated control calves had a geometric mean of 25,102 nematodes; groups 2, 3, and 4 calves given ivermectin at dose rates of 50, 100, or 200 micrograms/kg had reductions of 88.2%, 98.0%, and 99.8%, respectively.  相似文献   

14.
Anthelmintic efficacy of ivermectin against Mecistocirrus digitatus was evaluated in 10 naturally infected zebu calves. Group 1 (n = 5) was not treated, and group 2 (n = 5) was treated SC with 200 micrograms of ivermectin/kg of body weight. Calves were euthanatized 14 or 15 days after treatment. There was 100% overall reduction of M digitatus in treated calves, which was significant (P = 0.0079) compared with reduction in controls. Cooperia punctata, Haemonchus similis, and Trichostrongylus axei were found in controls. Efficacy against these parasites in treated calves was 100%.  相似文献   

15.
AIMS: To determine the reasons for pre-slaughter mortality and post-slaughter wastage in New Zealand bobby veal calves, and to assess compliance with the national animal welfare codes at a slaughter premises in New Zealand.

METHODS: The study was conducted at a single slaughter premises in Southland, New Zealand, during the 2011 bobby veal processing season. Calves that died during the pre-slaughter period underwent post-mortem examination to identify the reasons for death and notable secondary findings. Data from calves condemned at official post-mortem meat inspection were also analysed.

RESULTS: The mortality risk in the pre-slaughter period was 0.7% (288/42,494) and post-slaughter condemnation losses were 0.4% (180/42,206), resulting in a total loss to food production of 1.1%. Of the calves that were examined after dying in the pre-slaughter period (n=247), digestive tract disorders (41%) and omphalitis (23%) were the most common primary diagnoses. Secondary findings in these calves included absence of curd in the abomasum (25%), immaturity (21%) and emaciation (9%). Omphalitis (54%) and septicaemia (37%) were the most common causes of post-mortem wastage.

CONCLUSIONS AND CLINICAL RELEVANCE: Digestive tract disorders, omphalitis and septicaemia were the most common reasons for pre-slaughter mortality and post-mortem wastage. Further investigation of pre-transportation husbandry and feeding practices is indicated to determine compliance with animal welfare codes by farmers that supplied calves that had no curd in the abomasum, or were immature or emaciated on arrival at the slaughter premises.  相似文献   

16.
In this study, the prevalence of Giardia duodenalis infections was determined in Western Canadian and Western Australian dairy calves. Faecal samples were collected from Holstein calves located on a commercial dairy near Lethbridge, Alta., Canada (N=28) and from calves located on two commercial dairies located near Perth, WA, Australia (N=36). Faecal samples were examined for the presence of Giardia cysts using sucrose gradient centrifugation, followed by immunofluoresence microscopy. DNA was then extracted from Giardia isolates obtained from positive samples. A PCR based method was employed to amplify and sequence a 292bp region of the 16S-rRNA gene. Genetic sequences obtained from Giardia isolates were compared to each other and to previously sequenced isolates. Following a single faecal sample, 58% of Western Australian calves and 57% of Western Canadian calves were positive for Giardia. Geometric mean cyst counts/g of faeces were 839 for Western Australian calves and 3475 for Western Canadian calves, but these values did not differ significantly. Genetic sequences were obtained from 10 calves from Western Canada, while six sequences were obtained from Western Australian calves. Of the Western Canadian isolates, eight aligned with the proposed 'Hoofed livestock' genotype. Of the five isolates obtained from Western Australian calves, four sequences were identical to the 'Hoofed livestock' genotype. Two isolates from the Western Canadian calves and one isolate from the Western Australian calves had the identical genetic sequence to the Genotype (Assemblage) A sequence, a common human genotype. The results of this study demonstrate, for the first time, that Giardia infections occur in Western Australian calves. Also, calves from different geographical locations appear to be primarily infected with a Giardia genotype unique to hoofed livestock. However, calves can shed Giardia cysts potentially infective for humans. Thus, Giardia infections should be considered important to Australian dairy producers, and infections in calves may pose a risk to public health regardless of geographical location.  相似文献   

17.
A trial was conducted to determine the efficacy and pharmacokinetics of fehantel and ivermectin in six month-old red deer calves (C. eluphus). Five calves received febantel by mouth at 7.5 mg/kg, five received a subcutaneous injection of ivermectin at 200 microg/kg and five were controls. All calves were killed seven days later and total lung and gastrointestinal worm counts carried out. Febantel was 85 and 99.8% efficient in removing immature and mature Dictyocaulus viviparus, respectively, and ivermectin was 100% efficient in both cases. There was no gastro-intestinal nematodes in any of the treated calves, compared to an average of 619 in the control calves. The metabolism of febantel resulted in plasma levels of fenbendazole, oxfendazole and sulphone for which the common curves fitted by compartmental model peaked at values (standard errors)-of 0.46 (0.03), 0.41 (0.02) and 1.73 (0.07) mg/l after approximately five, nine, and thirteen hours and were undetectable at 30,72 and 120 hours respectively. There was considerable variation among animals in response to ivermectin. The fitted common curve had a peak plasma level of 15.8 (0.08) microg/l at 20 hours after injection, which had dropped to 7.9 (1.1) microg/l seven days after injection. It was estimated that after 15 days plasma levels of ivermectin would not be detectable. It is concluded that the injectable form of ivermectin tested is a highly efficient anthelmintic in deer, and that plasma levels persist for over a week after subcutaneous injection. Fehantel is very efficient against mature D. viviparus in deer, but its reduced efficiency against immature D. viviparus may relate to the deer;s ability to metabolise and excrete benzimidazoles more quickly than sheep and cattle.  相似文献   

18.
The immune system in juvenile calves is immature, so calves are susceptible to several diarrheal and respiratory diseases. Oral administration of lactic acid bacteria (LAB) is known to improve the growth performance and prevent diarrheal and respiratory diseases by stimulating the immune system in juvenile calves. Most of the immunostimulation by LAB is achieved by their cell wall components, and therefore we evaluated the immunostimulation of the cell preparation of Enterococcus faecalis strain EC-12 (EC-12) in juvenile calves in a clinical field. Twenty-nine 1-week old calves were used. Fourteen calves were administered 0.2% (w/w) of an EC-12 preparation that supplemented a milk replacer, and other calves were not supplemented. Feces and serum was collected at day 0, 7 and 49 after the administration to measure the IgA and IgG concentration. The fecal IgA concentration was increased by EC-12 administration at day 49, and the serum IgA concentration was also increased at day 7. These results suggested that oral administration of EC-12 in juvenile calves might have an immunostimulatory effect and provide earlier recovery of IgA levels in mucosal immunity.  相似文献   

19.
Twenty male Holstein calves averaging 105 kg in weight and naturally infected with gastrointestinal nematodes and small numbers of lungworm and hookworm, were given experimental infections with the two latter species to provide adult and larval stages for anthelmintic evaluation. Following random allotment, one group of 10 calves was injected subcutaneously with moxidectin at a dosage of 0.2 mg kg-1 of body weight. A second group of 10 was injected subcutaneously with unmedicated blank vehicle at a dosage of 1 ml per 50 kg of body weight. Fecal samples were examined before treatment and at 7 and 13 days after treatment. The 20 calves were necropsied for worm recovery at 13 and 14 days after treatment. All calves were positive for lungworm and hookworm on the treatment date. Treatment was 100% effective in elimination of hookworm eggs and lungworm larvae and 99.9% in reducing total egg counts at both 7 and 13 days after treatment. Moxidectin was 100% effective (P less than 0.01) in eliminating the following 11 species of nematodes. Dictyocaulus viviparus mature and immature adults (E5), Bunostomum phlebotomum adults and L4, Ostertagia ostertagi adults and early L4, Ostertagia lyrata adult males, Haemonchus placei adults. Trichostrongylus axei adults, Cooperia spp., including Cooperia punctata, Cooperia spatulata, and Cooperia pectinata adults, Oesophagostomum radiatum adults and Trichuris discolor adults. No adverse reactions to moxidectin treatment were observed.  相似文献   

20.
The pharmacokinetic determinants of doxycycline were calculated after a single IV administration of the drug (20 mg/kg of body weight) in 5 Angus calves with mature rumen function and 4 Holstein calves with immature rumen function. Doxycycline disposition was best described by means of an open 2-compartment model. Median elimination half-life was 14.17 hours (Angus) and 9.84 hours (Holstein). Mean (+/- SEM) total body clearance was 1.07 (+/- 0.06) and 2.20 (+/- 0.21) ml/min/kg in Angus and Holstein calves, respectively. Mean extent of doxycycline binding to serum proteins was 92.3% (+/- 0.8%). The large steady-state volume of distribution (1.31 +/- 0.11 L/kg in Angus and 1.81 +/- 0.24 L/kg in Holstein calves), despite the small free fraction in serum, suggested a relatively unrestricted access of drug into the intracellular compartment and/or appreciable tissue binding. Results of mass spectrometric analysis of serum and urine from calves administered doxycycline IV revealed absence of biotransformation, because only parent drug could be detected. Thus, doxycycline may be a valuable antibiotic for use in food animals pending further studies on tissue residues, safety, and efficacy.  相似文献   

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