No abstract

In the 1st trial, lasting 3 months, 24 cows in 2 groups were given daily 15 kg roughage and 3 kg concentrates without (control) or with soluble compounds of heavy metals (including As2O5) added to the concentrates to give Cd, Pb, Hg and As at 2, 50, 0.2 and 3.4 (control) and 152, 200, 1.7 and 33 mg/day (treatment) resp. In the 2nd trial, lasting 2-3 lactations, 32 cows in 4 groups were kept indoors and given daily 10 kg roughage and 10-11 kg concentrates without or with soluble compounds (including As2O3), harbour sludge or sewage sludge. Intakes of Cd, Pb, Hg and As by control cows were the same as those in the 1st trial, but for cows in the 3 treatment groups daily intakes averaged: Cd 32, 10 and 6 mg; Pb 200, 164 and 168 mg; Hg 1.7, 3.1 and 1.2 mg; and As 33, 21 and 6.8 mg. In neither trial did increased intakes of Cd, Pb, Hg or As lead to significantly increased concn. in milk or blood, and only As given in soluble compounds was increased in muscle from slaughtered cows (4/group in trial 1 and 1-2/group in trial 2). Concentrations of Cd, Pb, Hg and As in liver and kidney were all increased by the treatments, and particularly by soluble compounds, with concn. in kidney exceeding those in liver in all but 1 case. Cd also accumulated in spleen and thymus, Pb in bone, Hg in spleen, and As in heart, thymus, spleen and brain. Results are compared with those obtained in other carry-over studies. (Abstract retrieved from CAB Abstracts by CABI’s permission)

SUMMARY A possible association of a chronic indurative mastitis with mvv (maedi visna virus) infection in sheep was investigated. Sheep offour flocks (group A), in which insufficient lamb growth apparently associated with insufficient milk production and probably related to udder induration, was a serious problem, were clinically examined in mid-lactation. The results were compared with four mvv-free flocks (group B) without such complaints. The incidence of udder induration in group A (n= 263) was about eight times higher than in group B(n= 206): 63.1 versus 8.0%. The clinical picture differed essentially between the groups. In group A the udder abnormalities were of a diffuse and indurative nature, involving both udder halves, while in group B the udder lesions were mainly nodular and often limited to one udder half Bacteriological examination revealed a difference in infection rate of the udders (6.8% in group A versus 14.1% in group B). A substantial difference was observed in a comparison of the bacteriological infection rate of the clinically abnormal udders (5.4% in group A. versus 47.0% in group B).Serological examination with an indirect ELISA revealed 81% seropositive sheep in group A, versus 0% in group B. Twelve sheep of group A and five of B, culled for reason of mastitis, were selected for pathological examination. The gross and microscopic lesions showed a pronounced difference between both groups. In group A a diffuse interstitial mastitis with slight to moderate fibrosis and a pronounced lymphoid hyperplasia was observed. In group B the mastitis had a nodular character, with a chronic galactophoritis, extensive fibrosis. and in some cases chronic abscesses. The lesions were often limited to one udder half Among the necropsied ewes of group A, nine showed lesions characteristic of maedi, whereas in group B no such lesions were observed. The possible causal relation of this chronic indurative mastitis with mvv infection is discussed.

Summary Over a period of five years, the epidemiology of maedi‐visna virus (MVV) infection was studied by means of sequential serological examinations in a small flock of Texel sheep after the introduction of two infected ewes. The flock was managed as an average field flock except that seropositive sheep were kept in the flock as long as possible and that replacements were preferentially selected from progeny of seropositive ewes. The first seroconversion was observed after 11 months and was soon followed by three others. A year later, a considerable increase in the number of seropositives was observed and at the end of the experiment 20 of a total of 24 sheep (83.3%) had seroconverted. A total of 16 sheep were present in the flock during the whole study, of which 13 (81.3%) had become infected by horizontal transmission. Two sheep showed a clear but transient, and another sheep showed a weak and irregular seroresponse, whereas MV‐lesions proved to be present. When the flock was slaughtered, the mean age of the sheep was 5.25 years. Only a few sheep showed poor bodily condition; no other conspicuous clinical signs were observed. Nevertheless, a total of 70% of the infected sheep had maedi‐visna lesions in udder and/or lungs. Udder lesions were found in 78.6%, lung lesions in 42.9% and lesions in both organs were found in 21.4% of the affected sheep. The seronegative sheep were free of lesions. No arthritic lesions were found. A total of 22 fetuses from 13 seropositive ewes were virologically examined and none yielded MVV. Zusammenfassung Fünfjährige serologische Studie über die natürliche Verbreitung von Maedi‐Visna‐Virus in einer Schafherde, vervollständigt durch post mortem‐Untersuchung Die Epidemiologie der Maedi‐Visna‐Virus‐Infektion (MVV) wurde über einen Zeitraum von fünf Jahren durch sequentielle serologische Untersuchungen an einer kleinen Texel‐Schafherde verfolgt, in welche zwei infizierte Mutterschafe eingebracht worden waren. Die Herde wurde als Durchschnitts‐Feldherde geführt, mit Ausnahme der Tatsache, daß seropositive Schafe möglichst lange in der Herde belassen wurden, und daß Ersatz bevorzugt aus der Nachzucht seropositiver Muttertiere gestellt wurde. Die erste Serokonversion wurde nach elf Monaten beobachtet und war bald von drei weiteren gefolgt. Ein Jahr später ließ sich ein beachtlicher Anstieg der seropositiven Tiere erkennen, und am Ende des Experiments waren bei 20 von insgesamt 24 Schafen (83,3%) Antikörpertiter feststellbar. 16 Schafe waren während der gesamten Studie in der Herde, von diesen wurden 13 (81,3%) durch horizontale Verbreitung infiziert. Zwei Schafe zeigten eine deutliche, aber nur vorübergehende Serumantwort. Die eines anderen Tieres war schwach und unregelmäßig, außerdem traten Maedivirus‐Läsionen auf. Nach der Schlachtung der Herde lag das Durchschnittsalter der Tiere bei 5,25 Jahren. Nur wenige Schafe zeigten schlechte körperliche Verfassung; andere auffällige klinische Symptome wurden nicht beobachtet. Dennoch hatten 70% der infizierten Tiere Maedi‐Visna‐Läsionen im Eu...

An experiment was designed to study the clinical effects of different levels of carbadox, cyadox and olaquindox in the ration on health, weekly weight gain and feed conversion in pigs. Four different carbadox and olaquindox (25,50, 100 and 200ppm) levels and five different cyadox (25, 50, 100,200 and 400ppm) levels were tested in groups of 6 pigs during 6 weeks. The 13 groups were compared with a control group fed on the same diet with only vehicle.After one week the first clinical sign, a high faecal dry matter (FDM) content, was observed in the 200ppm carbadox group, followed by the 100 and 50 pprn carbadox, the 400 and 100 pprn cyadox, and the 200 and 100 pprn olaquindox groups two weeks later. A second clinical sign, urine drinking from the floor or from pen-mates, was observed in the same pens, occurring in the same sequence. The third important clinical sign, a decreased abdominal volume, was also observed in almost the same sequence, however, in the 50 pprn olaquindox and cyadox groups this clinical sign was not observed. Average weekly weight gain was significantly decreased in the higher carbadox and olaquindox groups. Weight gain was significantly increased in the 200ppm cyadox group. Hematocrit values were significantly increased in the 200 and 100 pprn carbadox groups only.From this study one may conclude that, within the dosages used, carbadox is more harmful than olaquindox for pigs, and it seems that cyadox is harmless for pigs in dosages up to 400 ppm.