Search

De laatste jaren is er een toenemende aandacht voor de mogelijke bijdrage van therapeutisch gebruik van antibiotica in de dierhouderij op de ontwikkeling van antimicrobiële resistentie. Een additionele bron van blootstelling van landbouwhuisdieren aan antibiotica is versleping via diervoeders. In principe levert iedere partij gemedicineerd voeder, meerdere spoelcharges op met residuen van antibiotica. Landbouwhuisdieren worden door dit 'door versleping' gecontamineerde voer onbedoeld blootgesteld aan antibiotica.

In Aquacultuur 2010, nr. 5 stond op pagina 33 van het artikel "Aan tafel bij Sietze Leenstra" de opmerking, dat antibiotica het immuunsysteem verstoren. Hier is wel iets voor te zeggen, maar toch moeten we oppassen, dat we niet alle antibiotica op één hoop smijten. Volgens de auteur is het vooral het gebruik van oxytetracycline in de aquacultuur, waar we een vraagteken bij moeten plaatsen.

In Aquacultuur 2010, nr. 5 stond op pagina 33 van het artikel "Aan tafel bij Sietze Leenstra" de opmerking, dat antibiotica het immuunsysteem verstoren. Hier is wel iets voor te zeggen, maar toch moeten we oppassen, dat we niet alle antibiotica op één hoop smijten. Volgens de auteur is het vooral het gebruik van oxytetracycline in de aquacultuur, waar we een vraagteken bij moeten plaatsen.

The Netherlands' Ministry of Health and the health insurance companies have drawn up a list of preparations which will no longer be reimbursed. The ocular antibiotic preparations Polyspectran and Terramycin are on the list. However, there are no satisfactory alternative with respect to the broadness of the antibiotic spectrum required. In addition, some alternatives have serious side effects or may induce bacterial resistance.

Sixteen dairy cows with chronic puerperal endometritis between 3 and 8 weeks post partum were treated with intra-uterine applied oxytetracycline (OTC) and lugol. OTC was rapidly removed from plasma and was not detectable after 48 hours. The concentration of OTC in milk did not exceed 40 micrograms/kg, and it was still detectable in milk 34 hours after treatment. The concentration of OTC in milk was always lower than the limit of 50 micrograms/kg used by milk-testing stations and the European limit (MRL) of 100 micrograms/kg. Milk from cows treated with lugol did not cause inhibition in the plate test.

Equine granulocytic ehrlichiosis (EGE) has been observed in the U.S.A., Brazil, Germany, Sweden, Switzerland and possibly in Great Britain. The causative agent is rickettsia Ehrlichia equi, identified for the first time in 1969. The clinical features of the disease are anorexia, fever, depression, (limb) oedema, icterus, ataxia, petechiae and orchitis. Hematologic changes are leukopenia, thrombocytopenia, anemia and cytoplasmic inclusion bodies in the neutrophils and eosinophils. Vasculitis may be observed at autopsy. Following a positive hematological diagnosis (Giemsa stained blood smear) of EGE, treatment with oxytetracycline can be initiated.

Serological surveys showed that equine monocytic ehrlichiosis (EME) occurs in the USA, Canada and Europe. The causative agent is Rickettsia Ehrlichia risticii, isolated for the first time in 1984. The clinical features of the disease are sluggishness, anorexia, colic and fever, possibly followed by watery diarrhoea. Complications of an infection with E. risticii are laminitis and abortion. Colitis of the ascending colon may be observed at autopsy. Following a positive serological diagnosis (IgM ELISA) of EME, treatment with oxytetracycline can be initiated. It is also important to restore the fluid and electrolyte balance by infusion. Prevention may be achieved by vaccination.

Pharmacotherapeutic, pharmacodynamic and pharmacokinetic aspects of oral mass medication with oxytetracycline (OTC) in pigs, calves and poultry are discussed in this review. Clinical studies with successful therapeutic results are scarce in literature; however, OTC is still frequently used for mass medication. Some practical advice to improve the bioavailability of OTC is given. This mainly concerns the reduction of the interaction between calcium ions and OTC. OTC may be useful for oral mass medication when applied as a prophylactic drug. Pharmacological studies are required in order to provide more knowledge about the efficacy of OTC-mass medication. Additional information can be acquired from the field by improving and extending the reciprocal co-operation between field veterinarians and diagnostic laboratories. This may lead to a more justified choice from the various possibilities of antimicrobial use in livestock.

Postparturient endometritis in cattle is discussed in this review paper, considerable attention being paid to diagnosis and treatment. Clinical examination is stressed in the discussion of diagnosis. The diagnosis of endometritis may be established by rectal and vaginoscopical examination in nearly every case. Cytological and bacteriological examinations supply only little information. In view of the method of treatment, it is essential to determine whether or not the cow is affected with pyometra. Treatment of acute postparturient endometritis consists in intra-uterine administration of oxytetracycline (for a period of from one to three days). Pyometra should be treated by injection of prostaglandins (PG). When it is doubted whether pyometra is developing and a corpus luteum is present, treatment is nevertheless advisable. All other cases of chronic endometritis do not require therapy. The tendency to spontaneous recovery is so considerable in cattle that treatment cannot add anything to the results.

The course run by the disease is described in a horse which showed the symptom complex of colitis X following treatment with oxytetracycline. Disseminated intravascular coagulation was also observed in this horse. The possibility of disseminated intravascular coagulation being part of colitis X is discussed.

The distribution of oxytetracycline hydrochloride in two batches of 4,000 kg of pig-rearing pellets (400 ppm) was studied. The stability of oxytetracycline in this feed was also determined. The concentration of oxytetracycline in the feed was determined by high pressure liquid chromatography. The premix contained more oxytetracycline (27 per cent) than the proportion stated. The results show that the first 1,000 kg of feed contained less (350 mg/kg) oxytetracycline than the other 7,000 kg (435 mg/kg). After producing 8,000 kg of feed with oxytetracycline, 4,000 kg of feed not containing oxytetracycline was produced. Still, this feed was found to contain 13 mg/kg of oxytetracycline. When the feed was stored for 150 days at a temperature of from 1 to 2 degrees C and again for 270 days at 20 to 25 degrees C, it contained 86.5 per cent of the oxytetracycline present after production of the feed.

Een tussenverslag van de onderzoekresultaten tot nu toe om te komen tot de gewenste onderzoekmethode. Uitgevoerd werden een drietal ringonderzoeken met de Melkcontrolestations en een Keuringsdienst van Waren en een vervolgonderzoek met een Melkcontrolestation en een Keuringsdienst van Waren.

The piglets of two multiplier herds (M and B) showing clinically apparent atrophic rhinitis (AR) were treated by the nasal-spray method. A solution of oxytetracycline hydrochloride (OTC, 50 mg/ml.) was used as a spray fluid. The course of the disease in the herds was followed by studying the development of foreshortening of the upper jaws in the heads. Brachygnathia superior (BS), from the eighth to tenth week of life. Efforts were made to gain an impression of the effects of treatment on the frequency with which Bordetella bronchiseptica and Pasteurella multocida were isolated by bacteriological examination of the nose. Treatment by the nasal-spray method up to an age of approximately five weeks, of seven weeks were treated at least once weekly. The proportion of animals in which the disease was clinically apparent decreased from 25 per cent to 0 per cent in herd M and from 41 per cent to 0 per cent in herd B. Treatment by the nasal-spray method up to an age approximately five weeks, in which feed medicated with OTC was also given up to the age of eight to ten weeks also had a satisfactory effect. The frequency with which Bordetella bronchiseptica and Pasteurella multocida were isolated, was reduced by treatment, elimination of these agents was not.

The following measures designed for the prevention of Atrophic rhinitis (AR) were compared. (1) Adopting the all in - all out system in separate farrowing quarters. The variation in age between piglets in a single farrowing house was confined to one to two weeks. (2) Treating the piglets with a combined preparation of penicillin, chloramphenicol, oxytetracycline hydrochloride or sulphonamides on the third, sixth and twelfth days of life. (3) Administering immune sera to piglets. (4) Vaccinating sows and piglets with Bordetella bronchiseptica vaccine and piggery--specific Pasteurella multocida vaccine. The various forms of treatment had a beneficial effect on the clinical picture in every case of Atrophic rhinitis. Moreover, the dosage of the antibiotic oxytetracycline hydrochloride as well as the titre of the immune serum were found to be factors in the prevention of AR. The pressure of infection with Bordetella bronchiseptica and/or Pasteurella multocida is a factor of major importance in the pathogenesis of clinically apparent AR in piglets under eight weeks. Maintaining infection at a low level is the main object in the control of AR. The more so as the knowledge available today does not make it possible to free piggeries from Bordetella bronchiseptica and Pasteurella multocida.

Atrophic rhinitis (AR) caused serious losses in a breeding herd including approximately 120 sows. The extent to which piglets were affected by AR was assessed by determining the degree of shortening of the upper jaw. Animals showing a crooked nose or grade two or more of shortening of the upper jaw were considered to be clinically positive. Grades three and four of the upper jaw were observed in those animals which were severely affected by Atrophic rhinitis. Treatment of all piglets up to about eight weeks of age by the antibiotic oxytetracycline hydrochloride directed against the bacteria Bordetella bronchisepica and Pasteurella multocida was successful in reducing the proportion of clinically affected piglets from 30 per cent to 0 per cent within eight weeks. There was found to be a positive relationship between the proportion of piglets infected with the two above bacteria at an age of about five weeks and the incidence of shortening of the upper jaw at an age of about eight weeks. The proportion of piglets with shortening of the upper jaw rose following a marked increase in the number of piglets in farrowing and flat-deck houses and as a result of the supply of inadequately medicated feed.

A fatting-calf suffering from an acute bronchi(oli)tis, was treated with antibiotics and dexamethasone. Although the pulmonary complaint healed, the patient died a few days later because of internal haemorrhage from an abomasal ulcer. The article makes a possible connexion between the therapy and the ultimate cause of death plausible.