The nature of pristine noble gases in mantle plumes

High-precision noble gas data show that the Hawaiian and Icelandic mantle plume sources contain uniquely primitive neon that is composed of moderately nucleogenic neon-21 and a primordial component indistinguishable from the meteoritic occurrence of solar neon. This suggests that Earth's solar-type rare gas inventory was acquired during accretion from small planetesimals previously irradiated by solar wind from the early sun. However, nonradiogenic argon, krypton, and xenon isotopes derived from the mantle display nonsolar compositions and indicate an atmosphere-like fingerprint that is not due to recent subduction.     

Effect of ensiled hop (Humulus lupulus L.) residues on plasma acetate turnover rate in sheep

An isotope dilution method using [1‐¹³C]sodium acetate was applied to determine the effect of feeding ensiled hop (Humulus lupulus L.) residues on plasma acetate turnover rate in six adult crossbred sheep. The sheep were fed 63 g/kg body weight (BW)^0.75/day of either mixed hay of orchardgrass (Dactylis glomerata L.) and reed canarygrass (Phalaris arundinacea L.) and round bale silage at 3:1 ratio (Hay‐diet), or another where round bale silage was replaced by ensiled hop residues (Hop‐diet) with a crossover design each of a 3‐week period. The isotope dilution method was performed on day 21 of each dietary treatment. Dry matter digestibility was similar between diets, and nitrogen (N) digestibility was lower (P = 0.001) for Hop‐diet than Hay‐diet. However, N retention did not differ between diets. Plasma acetate concentration was lower (P = 0.04) for Hop‐diet than Hay‐diet, and the turnover rate of plasma acetate did not differ between diets. Plasma concentration of lactate and non‐esterified fatty acids were similar between diets. Hop‐diet was found almost comparable to Hay‐diet on plasma acetate turnover rate in the present experimental conditions. Therefore, it could be concluded that hop residues partially could be used as an alternative to traditionally used round bale silage for rearing sheep.     

The dispersal of Culicoides brevitarsis in eastern New South Wales and associations with the occurrences of arbovirus infections in cattle

Distributions of the vector Culicoides brevitarsis Kieffer (Diptera: Ceratopogonidae) (determined from light trap data) and 2 arboviruses (determined from seroconversions in sentinel cattle) were studied in eastern New South Wales in 1993–94. C brevitarsis was recorded progressively from endemic areas on the north coast, to Nowra on the south coast, and westward to Scone, in the Hunter Valley. C brevitarsis also survived through winter at Paterson, in the Hunter Valley. Its apparently focal reappearance in this marginal area had no obvious effect on the broad pattern of its progression or the dispersal of Akabane and bluetongue viruses. These viruses were first recorded from foci near Coffs Harbour, on the mid-north coast. Their first occurrences at different locations were associated with those of C brevitarsis, but not with each other. The viruses were found only within the recorded limits of the vector's distribution. Delays between the initial occurrence of C brevitarsis and first evidence of virus transmissions at locations ranged from 2 to 7 months. The delays decreased away from the points of focus and were negatively associated with the time of initial occurrence of the vector. Seroconversions to the viruses were related to the presence of C brevitarsis. However, the densities of C brevitarsis had no apparent effect on the initial numbers of cattle seroconverting to either virus. The results support the conclusion that the progressions of C brevitarsis and Akabane and bluetongue viruses were the result of gradual movements by the vector.     

Diarrhoea in Merino ewes during winter: association with trichostrongylid larvae

SUMMARY A study on 3 farms, each having a preventive strategy for the control of nematode infections, determined the risk factors associated with diarrhoea among Merino ewes in winter. Comparisons were made among groups of mated and unmated ewes with and without treatment with controlled-release capsules containing albendazole. Diarrhoea was assessed from the accumulations of faeces around the breech (dag score) and related to worm egg counts, total worm counts and histopathological findings. The overall prevalence of severe dag in ewes not treated with a capsule was 26% (221/844). In comparison, only 2.7% of treated ewes had severe dag. The adjusted odds ratio on each farm indicated that untreated ewes were between 12 and 16 times more likely to be affected with severe dag than ewes treated with a capsule. The effect of lactation was significant on only one farm whereas initial body weight had no significant effect. There was no significant association between worm egg counts and the occurrence of severe dag. There were significantly more eosinophils in the small intestine of ewes affected with severe dag compared with unaffected ewes. There were no significant differences in mast cell and globule leucocyte numbers between affected and unaffected ewes. This study provides strong evidence that the main cause of diarrhoea among Merino ewes grazing winter and early spring pastures is the ingestion of trichostrongylid larvae even by sheep that have a well-developed protective immune response to these parasites. New strategies for the control of nematode infections are needed to prevent diarrhoea and dag formation in adult sheep.     

Pathomorphological changes in the skeletal muscles (musculus longissimus dorsi) in swine following varied transport stresses and resting periods prior to slaughter

The M. longissimus dorsi of 171 pigs were histologically examined for pathological signs. Acute hyaline-plaque degenerations and necrosis (hsD/N) in various degrees of manifestation were recorded from 42.7 and hyaline transverse ligaments (hQb) from 22.8 per cent of all cases. The occurrence of hsD/N following container transport was lower with significance (33.3 per cent) than that following lorry transport (50.5 per cent). The form of transport failed to have any substantive effect on the occurrence of hQb, the figures being 20.5 per cent for container and 24.7 per cent for lorry. Short resting periods, between 0.5 and 1.2 hours, were followed with significantly higher occurrence of hsD/N, as compared to longer resting periods, between five and eight or 23 hours. These pathological findings were not further reduced by extending the resting period from something between five and eight to 20 hours. The pathological hsD/N and hQb findings were recordable from both PSE pork (hsD/N = 51.4 per cent, hQb = 25.7 per cent) and from pork without any quality shortcomings (hsD/N = 39.7 per cent, hQb = 22.1 per cent), but the number of hsD/N cases in the context of PSE pork tended to be higher than that in high-quality pork. No sex dependence was established. The results are discussed under the aspect of aetiopathogenesis of stress-borne myopathy.     

Epizootiology of bovine cysticercosis in the Jindrichuv Hradec District

The results of the study of the epidemiology and epizootology of Taenia saginata in the Jindrich?v Hradec district indicate that this tapeworm species has adapted successfully to anthropogenic conditions. Mass occurrence of bovine cysticercosis, coming from a limited source, was observed in the Jindrich?v Hradec district. Our of the 907 employees of one farm, T. saginata was found in two workers engaged in animal production and in one person working in crop production. Their recovery resulted in the eradication of cysticercosis in the cattle kept on that farm; before eradication the disease was responsible for losses of several hundreds of thousands of crowns.