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Biomedical subjects

J F Michel

Publications and source records attributed to J F Michel.

At least 37 records · Page 2Linked to original sources
PubMed1982

Effect of anthelmintic treatment on the milk yield of dairy cows in England, Scotland and Wales.

One hundred and twenty dairy herds collaborated in a trial to determine the effect on milk yield of anthelmintic treatment given at calving. Cows and heifers were divided into five groups. Three were each given a different anthelmintic: thiabendazole, fenbendazole or levamisole. One group was given a placebo and the fifth was untreated. Analysis of data from 9000 lactations showed a treatment effect just significant at the 5 per cent level, of 42 kg milk, 1.8 kg fat and 1.4 kg protein. There was no evidence that the three anthelmintics differed in their effect on yield. The effect of treatment was not greater in heifers than in cows, nor was there a difference between spring and autumn calvers. There was no indication that the effect of treatment was markedly greater in some herds than others and it was not related to periparturient faecal egg count.

Animals↗
PubMed1981

Worm burdens of dairy heifers in England and Wales.

The size and composition of abomasal worm burdens from 143 casualty and cull dairy heifers were estimated. Over 60 per cent had totals of less than 10,000, only four exceeded 100,000 and the overall mean was 16,285. Ostertagia ostertagi was almost always present and usually formed the major proportion of the total. Trichostrongylus axei was recorded in 83 heifers and was the most common species on 17 occasions. The numbers of arrested early fourth stage worms were highest in winter and declined rapidly during spring. O lyrata was only found when O ostertagi was present and always as a small percentage of the total. Similarly in the case of two of the minor species, Skrjabinagia kolchida (= Grosspiculagia podjapolskyi) was never found independently of O leptospicularis (= O crimensis). These relationships are regarded as suggestive of polymorphism.

Animals↗
PubMed1981

Further observations on the action of fenbendazole against inhibited fourth stage larvae of Ostertagia ostertagi.

Two further trials are reported on the effect of fenbendazole on inhibited Ostertagia ostertagi larvae. In the first trial fenbendazole successfully eliminated inhibited burdens of O ostertagi, while in the second trial the effect was variable. As a result of these trials and previous reports it is concluded that a single oral dose of fenbendazole cannot be relied upon to prevent winter (type 2) ostertagiasis.

Animals↗
PubMed1981

Use of anthelmintics for cattle in England and Wales during 1978.

A study of anthelmintic treatments received by 40,000 cattle during 1978 on a random sample of 240 farms in England and Wales showed that most were given against gastrointestinal nematodes for purposes of prophylaxis. Analysis of the data indicates that of an estimated pounds 15m spent on anthelmintics and their administration, most was far less effectively employed than it might have been. Errors of three kinds were common, some classes of cattle being dosed unnecessarily, animals being dosed at an unfavourable occasion or time of year, and anthelmintics being directed at parasites against which they had no action. Existing knowledge on the control of helminths is not effectively used; most dosing was done without advice from an identifiable source.

Animals↗
PubMed1980

Maximum duration of sustained /s/ and /z/ in children.

It has been proposed in the clinical literature that a ratio of the maximum duration of /s/ to /z/ may be useful in determining the possible contribution of the respiratory and vocal mechanisms to a disordered voice. The purpose of this study was to obtain preliminary normative data for the maximum phoneme duration (MPD) of /s/ and /z/ and to determine the ratio of /s/ to /z/ in five, seven, and nine year olds. The results indicated that while there were no significant differences in MPD for either /s/ or /z/ between males and females at any one age level, there was a significant increase in the MPD of /s/ and /z/ for both sexes as a function of age. When the ratio of /s/ to /z/ was computed for the subjects, there were no significant differences in these ratios between males and females nor were there significant differences as a function of age.

Age Factors↗
PubMed1979

The effect of age, acquired resistance, pregnancy and lactation on some reactions of cattle to infection with Ostertagia ostertagi.

An experiment is described in which the effects of age, previous infection, pregnancy and lactation on some reactions of cattle to infection with Ostertagia ostertagi were studied. It was found that an acquired resistance to the establishment of worms developed more rapidly in 20-month-old heifers than in calves, that it was unaffected by pregnancy of the host but that it was largely lost by heifers in early lactation. The rate at which populations were turned over, i.e. the mean life-span of worms through the late 4th and 5th stages was unaffected by the factors studied. Although, in the conditions of the experiment, development of the worms was not arrested in susceptible calves, both age of the host and its previous experience of infection were significant causes of arrest, and in previously infected 20-month-old cattle 86% of the worms of a challenge infection were arrested. Pregnancy did not affect the proportion of worms that was arrested but in lactating heifers only marginally more worms were arrested than in calves. Worms that were not arrested grew more rapidly in calves and in lactating heifers than in empty heifers or those in mid-pregnancy.

Age Factors↗
PubMed1978

Plasma pepsinogen levels in some experimental infections of Ostertagia ostertagi in cattle.

Two groups of calves were infected with larvae of Ostertagia ostertagi to establish large numbers of adults and arrested larvae. In one group symptoms of ostertagiasis were seen and there was a loss of three months growth; in the other, in which adult worms were removed by a single anthelmintic treatment, there was only a transient reduction in live-weight gain. Plasma pepsinogen levels were however the same in the two groups and followed the same course. Even after 25 weeks, when calves had been growing normally for up to three months, plasma pepsinogen values were still around 5 iu per litre, well above the level generally regarded as diagnostic of ostertagiasis. The relevance of these findings to the use of the test in the diagnosis of ostertagiasis is discussed. The literature is reviewed.

Animals↗