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Query: UMLS:C0851341 (infestation)
 10,121 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

An epidemiological study aimed at defining gastro-intestinal parasitism in sheep qualitatively and quantitatively was carried out in the Limousin area in France. Five lambs were sacrificed regularly every 4 weeks from May till January of the following year. Complete parasite counts were performed on these animals as well as measurements of the plasma level of pepsinogen. In order to define the influence of parasitism on the growth of the animals, the weight gains of lambs treated regularly and untreated lambs were compared. The results of post-mortem examination show that parasitism is mainly linked to the incidence of strongyles. Other observations in the flock have shown that Moniezosis may also play a non-negligeable part. The parasitic level, already high after one month at pasture, reached its maximum in July-August 1977 and was marked by a very high level of parasitism. Among these species found, two played an essential part: Ostertagia circumcincta and Haemonchus contortus. A study of the growth of the lambs showed that within 6 months, the weight gain of the treated animals was twice that of the untreated animals. The effects of parasitism were worsened by the low fodder value of the pasture and the occurrence of overgrazing. The blood pepsinogen measurements confirmed the usefulness of this technique in establishing the mean level of infestation of a flock by parasites of the abomasum. It seems that in some cases it could help to define the succession of peaks of infestation by different species.
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PMID:Study of gastro-intestinal stronglyosis in a sheep flock on permanent pasture. 1. Sheep parasitism in 1977. 54 22

The prophylactic effect of an albendazole containing 'pulse release' bolus on gastrointestinal helminth infection in calves during their first grazing season was tested on a farm in the Netherlands in 1986. Thirty calves were divided into two groups of young calves and two of old calves. On being turned out to grass, calves of one of these groups were given a bolus containing 3 x 2 grammes of albendazole, to be released after thirty-one, sixty-two and ninety-three days. The treated young calves showed a much lower egg-output, produced a lower infestation of herbage, displayed significantly lower pepsinogen levels and showed a significantly better gain in weight compared with the untreated young calves. Differences were not observed between the two groups of older calves, probably because of the fact that one of the treated calves had lost the bolus at an earlier stage.
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PMID:[The prophylactic effect of albendazole containing a pulse-release bolus on gastrointestinal helminth infection in calves]. 338 96

In an experiment carried out in 1981 and 1982, the effect of the use of a morantel sustained release bolus (Paratect bolus) on the weight gain and a number of parasitological parameters of cattle was studied. In the first year 42 calves were divided into 3 equal groups, one group was kept outside and treated with a bolus (B), the second group was kept outside and was not treated (C), while the third group remained indoors (I). Groups B and C were grazed separately on contaminated pasture. During the first months Group B had a negligible egg output. The egg output in the controls was much higher and in mid-August they had to be treated for parasitic gastroenteritis. At the end of the grazing season the advantage in weight gain of Group B was 20 kg compared with the controls. During the housing period the growth in the 3 groups was not significantly different. At the start of the second grazing season half the animals of Groups B, C and I received a bolus (Groups BB, CB and IB). The other half remained untreated (BC, CC and IC). The animals treated with a bolus in 1982 gained significantly more weight (64 g/day) than untreated animals. Heifers turned out for the first time (IB and IC) showed much less weight gain than heifers in their second grazing season. The heifers which had previously grazed in 1981 had a very low egg output compared with Groups IB and IC, although the level of egg output of the latter was also not very high (max, almost 40 (eggs per gram (EPG)). In faecal cultures of heifers of Group BC, CB and CC, no Cooperia oncophora-larvae were seen from May onwards, indicating a strong immunity against this species. In Group BB very low numbers of C. oncophora-larvae were observed. In Groups IB and IC, C. oncophora was present during the whole season. At the end of the first season the level of herbage infestation on the control pastures was much higher. In 1982 only slight differences in level of infestation between the pastures were observed. At the start of the season in 1982 serum pepsinogen levels were much higher in the groups which grazed in 1981, compared with the indoor-fed groups. Groups BC and CC had significantly higher levels than Groups BB and CB and all 4 groups always had higher levels than Groups IB and IC.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Effects of the use of a morantel sustained release bolus in first and second year grazing cattle. 404 26

In experiments carried out under field conditions with calves reared free from parasites and kept on pastures contaminated with Ostertagia larvae, the natural pattern of infestation with this parasite in calves was studied. It was shown that calves turned out early (late in April) developed a much higher primary (overwintered) infestation than calves turned out six weeks later on mown pasture. During the grazing season the serum pepsinogen levels were more indicative of the severity of the infestation than was the egg output. There also was a correlation between the serum pepsinogen level and loss of weight. During the housing period following the first grazing season, adult worms were eliminated more rapidly than inhibited fourth-stage larvae, resulting in a worm population consisting of up to 90 per cent EL-4 at the end of the housing period in April.
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PMID:[The natural pattern of Ostertagia-infections in cattle (author's transl)]. 742 71

In two experiments groups of calves were exposed to different levels and patterns of infection with Ostertagia spp. and Cooperia spp. The experimental design simulated the stereotypic pattern of herbage infestation, including a normal or a delayed midsummer increase, under conditions of set-stocking. The purpose of the experiments was to investigate the accuracy of egg counts, pepsinogen and gastrin values and antibody titres as estimators of the level of exposure to infection. Faecal egg counts significantly reflected levels of exposure during the first half of the simulated grazing season. Antibody titres and pepsinogen values reflected levels of exposure best during August and September, partly depending on the pattern and range of levels of exposure. Antibody titres against Cooperia spp. were particularly useful when levels of exposure to gastrointestinal nematode infection were low. Gastrin values were elevated only at high levels of exposure, which caused large weight gain reductions, in the later part of the simulated first grazing season. It is suggested that antibody titres and pepsinogen values can be used for prognostic diagnosis, indicating whether or not control measures should be taken. Both estimators of infection correlated significantly with the realised weight gain at the end of the simulated grazing season. Egg counts in the second month after the initial infection (turnout) also may be of significant value to support decisions concerning control measures. Comparisons with data from field trials and experiments conducted by others under various conditions suggested that the conclusions of the present experiments are also valid under field conditions. Furthermore, the results supported the conclusions drawn from previous field work, that levels of exposure are often very low on commercial farms in the Netherlands.
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PMID:Quantitative estimation of the level of exposure to gastrointestinal nematode infection in first-year calves. 772 24

In two experiments groups of calves were exposed to different levels and patterns of infection with Ostertagia spp. and Cooperia spp. The experimental design simulated the stereotypic pattern of herbage infestation, including a normal or a delayed midsummer increase, under conditions of set-stocking. After this simulated 'first grazing season', calves were monitored throughout the subsequent winter housing period. No continuing negative effects of previous infection on growth performance were observed. Calves in all groups gained on average over 0.7 kg day-1, irrespective of previous level of exposure. Differences between the experiments with respect to either level or pattern of infection during the preceding 'first grazing season' were all, to a greater or lesser extent, reflected in faecal egg counts, pepsinogen values, gastrin values and antibody titres against Cooperia spp. or Ostertagia spp. Depending on the time of sampling, pepsinogen values and antibody titres against Ostertagia spp. particularly were useful variables for assessing differences in levels of infection to which groups of calves had been exposed.
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PMID:Weight gain and the course of some estimators of gastrointestinal nematode infection in calves during winter housing in relation to the level of exposure during the previous grazing season. 773 55

Comparative analyses of the patterns of gastrointestinal nematode infections of first-grazing season cattle in Belgium are presented. The analysis involves 17 studies covering a 10 year period on 13 different farms in Flanders, Belgium. In all studies the calves were divided into an untreated control group, and one or two groups treated with chemoprophylactic systems. Two general infection levels emerged-'sub-clinical' (14 studies) and 'clinical' (three studies). The 'sub-clinical' infections were characterised by no clinical signs of parasitic gastroenteritis in the untreated control groups. Mean faecal egg counts remained low (less than 200), maximum pepsinogen levels only reached about 3500 mU tyrosine, and very small reductions in overall daily weight gain were observed compared with calves given chemoprophylaxis (less than 40 g day-1). Based on these results, on these 'sub-clinical' farms, chemoprophylaxis may not have been needed. In contrast, multiple salvage treatments of the control calf groups were required in the 'clinical' infections. Even with these salvage treatments mean faecal egg counts were high (more than 300), maximum pepsinogen levels were over 5500 mU tyrosine and there was a very large reduction in overall daily weight gain (more than 300 g day-1). However, it was not possible to predict either at turnout, or during the first month afterwards whether an infection on a particular farm would develop into a 'clinical' infestation. With the present data this prediction was possible from 8 weeks (Day 56) onwards, based on faecal egg counts and pasture larval contamination. It was also possible to predict using serum pepsinogen levels on Day 84. Therefore, one possible strategy for the effective control of gastrointestinal nematode infections of calves in temperate regions would be to evaluate faecal egg counts 2 months after turnout, and then only start treatment (i.e. metaphylaxis) if required.
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PMID:Gastrointestinal nematode infections of first-season grazing calves in Belgium: general patterns and the effect of chemoprophylaxis. 918 35

The objective of the present study was to determine the dynamics of infestation of cattle and pasture by gastrointestinal nematodes in a mild humid environment in northwestern Spain. For this, infestation of pasture by free-living stages (L3), dynamics of faecal egg output, blood pepsinogen levels and worm burden in slaughtered animals were quantified. The results showed a high degree of annual variability, which was dependent on weather conditions. The seasons were clearly defined in the study area, with mild humid winters and relatively dry summers registered throughout the years of the study. Infestation of pasture by larvae varied from year to year, peaking during August in the first year, between August and December in the second year, and during October in the third year. The annual variation was mainly due to weather conditions, particularly the amount of rain in summer. The patterns of faecal egg output were similar in the first and third grazing seasons, with maximum levels observed in May/June; however, in the second year, the peak was reached in October. Blood pepsinogen levels increased from pasture turnout (March/April) until the end of the grazing season (November/December), reaching maximum values from August/September onwards. The nematode parasite species identified at necropsy were Ostertagia osteragi, O. lyrata, Cooperia oncophora, C. macmasteri, C. punctata and Trichuris ovis, with O. ostertagi and C. oncophora predominating. In faecal cultures, the following genera were also identified: Haemonchus, Trichostrongylus, Nematodirus, Bunostomum, Oesophagostomum and Strongyloides. There was a significant correlation (r=0.97, P<0.01) between worm burden (Ostertagia spp.) and pasture infestation (Ostertagia L3) 3 weeks prior to slaughter of the calves, and also between blood pepsinogen levels and pasture infestation by Ostertagia L3 (r=0.33, P<0.02). Correlations between worm burden and faecal egg output and between blood pepsinogen level and faecal egg output were not significant. The results obtained in the present study confirm that there is annual variability in the time-course of nematodosis in cattle, and demonstrate the importance of weather, particularly summer rainfall, in an Atlantic temperate environment.
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PMID:Dynamics of infestation of cattle and pasture by gastrointestinal nematodes in an Atlantic temperate environment. 1706 22