Diagnosis of naturally occurring Fasciola hepatica infections in cattle with an enzyme-linked immunosorbent assay

Sera from 100 herds of cattle located in the state of Washington were examined with an enzyme-linked immunosorbent assay for antibody to Fasciola hepatica in a screening procedure that included 5 to 10 samples/herd. Twenty-eight herds contained infected cattle and F hepatica was most prevalent in 3 distinct geographic areas. Subsequent retesting of all sera available from 14 herds (mean of 109 samples/herd) revealed that the screening procedure correctly detected 7 of 7 operations in which greater than 40% of samples were positive or suspect and 3 of 3 operations in which 12% to 13% of the samples were positive or suspect. One of 3 herds considered negative after screening was found to contain a few (7%) positive samples and 1 herd considered possibly infected was negative on retest. These results were compared with those obtained by fecal examination for F hepatica eggs in 9 of the 14 herds. A good correlation (5 of 5) was found in which a high percentage (48% to 85%) of sera were positive or suspect. Fasciola eggs were not found in samples from 2 herds with few (7% to 12%) positive or suspect sera or in 2 herds that were negative by an enzyme-linked immunosorbent assay.     

Sequential study of lesion development in experimental haemophilus pleuropneumonia

Recently weaned pigs were infected aerogenically with Haemophilus (Actinobacillus) pleuropneumoniae, serotype 5. At three, six, 12, and 18 hours and one, two, four and seven days after exposure to haemophili a pair of animals were killed and necropsied. Pulmonary oedema with multifocal petechial haemorrhages and a diffuse neutrophilic bronchiolitis and alveolitis were observed at three and six hours after infection. Focal areas of coagulative necrosis developed in areas of intense suppuration at 12 and 18 hours after infection. At one and two days after infection, necrotic areas were surrounded by dense bands of degenerating leucocytes and contained unidentifiable round and elongated cells characteristic of this disease. In subacute lesions a thick layer of granulation tissue formed around the outer margin of developing abscesses. Most of the round and elongated cells in alveolar exudates could not be identified by enzyme histochemistry or electron microscopic examination. Neutrophils in various stages of degeneration and deterioration provided strong evidence that some of the cells were of this type. These findings suggest that neutrophils may play an early and significant role in development of lesions.     

Energy and nitrogen metabolism of chickens infected with either Eimeria acervulina or Eimeria tenella.

1. The effects of sublethal infections of E. acervulina and E. tenella on the energy and nitrogen metabolism of groups of five broilers aged 16 d were studied for 16 d in respiration chambers. 2. The metabolisable energy content of the diet for chickens infected with E. acervulina was 0.689 of its gross energy content and N retention was 42.5 g/100 g N intake compared with 0.738 and 47.1 g respectively, in uninfected pair-fed controls. Chickens infected with E. tenella were similarly affected. 3. Efficiency of utilisation of ME by chickens infected with E. acervulina was 0.43 during the first 8 d after infection, and 0.52 during the second 8 d compared with an overall efficiency by non-infected chickens fed ad libitum of 0.73. Maintenance energy requirement of infected chickens was higher during the first 8 d after infection than during the second 8-d period. 4. Body composition measurements showed that of the total gain in weight of chickens infected with E. acervulina, only 7.5 g/kg gain was fat and 213 g/kg was protein compared with 45 g and 210 g respectively for non infected chickens fed ad libitum. 5. E. acervulina and E. tenella infections reduced the apparent digestibility of total mineral, calcium and phosphorus.     

Ethanol can contribute to energy and environmental goals

To study the potential effects of increased biofuel use, we evaluated six representative analyses of fuel ethanol. Studies that reported negative net energy incorrectly ignored coproducts and used some obsolete data. All studies indicated that current corn ethanol technologies are much less petroleum-intensive than gasoline but have greenhouse gas emissions similar to those of gasoline. However, many important environmental effects of biofuel production are poorly understood. New metrics that measure specific resource inputs are developed, but further research into environmental metrics is needed. Nonetheless, it is already clear that large-scale use of ethanol for fuel will almost certainly require cellulosic technology.