Clinical and pathological responses of weaned pigs to atmospheric ammonia and dust

Nine hundred and sixty weaned pigs were exposed for five weeks to controlled concentrations of atmospheric ammonia and dust in a single, multifactorial experiment. The treatments were a mean dust concentration of either 1.2, 2.7, 5.1 or 9.9 mg/m3 (inhalable fraction) and a mean ammonia concentration of either 0.6, 10.0, 18.8 or 37.0 ppm, concentrations representative of commercial conditions. The experiment was carried out over two years and the pigs were used in eight batches, each consisting of five lots of 24 pigs. Each treatment combination was replicated once, and an additional control lot (nominally 0 mg/m3 dust and 0 ppm ammonia) was included in each batch. The dust concentration was the same in the other four lots in each batch in which the four concentrations of ammonia were used; thus, the split-plot design was more sensitive to the effects of ammonia than dust. The groups of pigs were kept separately in five rooms in a purpose-built facility, and the pollutants were injected continuously into the air supply. Ammonia was supplied from a pressurised cylinder, and the endogenous dust in each room was supplemented by an artificial dust manufactured from feed, barley straw and faeces, mixed by weight in the proportions 5:1:4; its ingredients were oven-dried, milled and mixed, and then resuspended in the air supply. The health of the pigs was assessed in terms of general pathology, respiratory tract pathology, and the microbiology of the nasal cavity, trachea and lung. In each batch, postmortem examinations were carried out on 40 pigs after five weeks' exposure to the pollutants and on 30 pigs two weeks later to test for carryover and recovery--a total of 560 pigs. These examinations revealed minimal gross pathology and widespread minor pathological changes of little significance. The pigs' turbinate and lung scores were low and unaffected by exposure to pollutants. All the putative bacterial pathogens, with the exception of toxigenic Pasteurella multocida type D, were isolated from the respiratory tract of the pigs of both ages, but there were no differences between the effects of the different concentrations of pollutants.     

Pharmacokinetics of sulfamethazine in male, female and castrated male swine

The concentration of sulfamethazine in plasma and sulfamethazine and its metabolites in urine were compared in male, female and castrated male swine. A surgical technique for placement of catheters in the urinary bladder was used to facilitate the collection of urine in males and castrated males. The elimination rate of sulfamethazine from plasma and the excretion of parent drug and metabolites into urine did not differ significantly among females, males and castrated male swine.     

LESIONS CAUSED BY CORYNEBACTERIUM PSEUDOTUBERCULOSIS IN THE SCROTUM OF RAMS

SUMMARY Palpable lesions within the scrotum but not associated with the testis or epididymis were detected in 20 of 200 merino rams in 3 flocks during routine veterinary examination. In 13 of 15 rams further examined Corynebacterium pseudotuberculosis was isolated from the lesions, which were typical CLA type abscesses. C. pseudotuberculosis was not shed in semen, and semen quality was normal in all affected rams.     

Portland cement: pseudomorphs of original cement grains observed in hardened pastes

Scanning electron micrographs show that a hydration product forms inside the anhydrous cement grains and forms a pseudomorph of the original cement grain. The originally water-filled space between the grains is partially filled with calcium hydroxide crystals that appear to be responsible for the strength of the cement paste.     

Soil and agronomic factors associated with cadmium accumulations in kidneys of grazing sheep

SUMMARY Mean concentration of cadmium (Cd) in kidneys of hogget sheep from 67 flocks grazing in the Agricultural Region of Western Australia was tested for association with soil, pastoral, climatic and nutritional factors. Hoggets grazing pastures on acidic soils and soils with a sandy-textured surface had higher Cd concentrations in kidneys than hoggets grazing pastures on more alkaline soils or soils with a clay-textured surface. Application of more than 100 kg of phosphatic fertiliser during the past 3 years to loamy soils was also associated with greater Cd concentration in kidneys of the grazing animals.     

Further evaluation of the use of buparvaquone in the infection and treatment method of immunizing cattle against Theileria parva derived from African buffalo (Syncerus caffer).

Three experiments were undertaken to determine the efficacy of different doses of buparvaquone in the infection and treatment immunization of cattle against Theileria parva derived from African buffalo (Syncerus caffer). Two of these experiments also compared buparvaquone with standard doses of long- and short-acting formulations of oxytetracycline. In addition, different dilutions of stabilates were used in the experiments. In the first experiment, a 10(-1.0) dilution of stabilate was used to infect groups of cattle treated with buparvaquone at doses of between 5 and 0.625 mg kg-1 body weight (bwt) on Day 0 after infection. All control cattle developed severe theileriosis and none of the treatment regimes (including those utilizing long-acting oxytetracycline) prevented the development of theileriosis. Treatment with buparvaquone at 2.5 mg kg-1 bwt or oxytetracycline gave the most satisfactory results. In the second experiment when the sporozoite dose was reduced to 10(-2.0) dilution, buparvaquone treatment at 5 and 2.5 mg kg-1 bwt and short- and long-acting formulations of oxytetracycline reduced reactions greatly. While all the oxytetracycline treated animals produced a serological response and were immune to a 50-fold higher challenge with the immunizing stabilate, several animals in the buparvaquone groups did not show a serological response and were not immune to challenge. In the third experiment, groups of cattle were infected with 10(-1.2), 10(-1.4) and 10(-1.6) dilutions of stabilate and were treated with 2.5 mg kg-1 bwt of buparvaquone. No animals developed severe theileriosis and all seroconverted. On homologous challenge, however, two out of 14 cattle showed severe reactions. It was concluded that further work on immunization using buparvaquone treatment at 2.5 mg kg-1 bwt and 10(-1.6) dilution of the stabilate would have to be carried out before such a system could be used in the field.