Noninfectious factors associated with pneumonia and pleuritis in slaughtered pigs from 143 farrow-to-finish pig farms

A cross-sectional study involving 143 farrow-to-finish herds was carried out to identify herd-level noninfectious factors associated with pneumonia and pleuritis in slaughter pigs. Data related to herd characteristics, biosecurity, management and housing conditions were collected by questionnaire during a farm visit. Climatic conditions were measured over 20 h in the post-weaning and finishing rooms where the slaughter pigs were kept. After these on-farm investigations, the finishing pigs were examined at slaughter for lung lesions. A sample of 30 randomly selected pigs per herd was scored for pneumonia and pleuritis. Herds were grouped into three categories according to their pneumonia median score (class 1: ≤ 0.5; class 2: 0.53.75). For pleuritis, a herd was deemed affected if at least one pig had a high pleuritis score (≥ 3). A multinomial logistic regression model was used to identify factors associated with pneumonia classes 2 and 3. A logistic regression for binary outcome was used to identify risk factors for severe pleuritis. An interval of less than four weeks between successive batches (OR=4.5, 95% confidence interval (95% CI): 1.5-13.6, p<0.01), large finishing room size (OR=4.3, 95% CI: 1.6-11.6, p<0.01) and high mean CO(2) concentration in the finishing room (OR=4.2, 95%CI: 1.6-11.3, p<0.01), significantly increased the odds for a herd to be in class 2 for pneumonia. The same risk factors were found for class 3 and, in addition, a direct fresh air inlet from outside or from the corridor in the post-weaning room vs an appropriate ceiling above the pigs (OR=5.1, 95% CI: 1.4-18.8, p=0.01). The risk for a herd to have at least one pig with a high pleuritis score was increased when the farrowing facilities were not disinsected (OR=2.7, 95% CI: 1.2-5.8, p=0.01), when tail docking was performed later than 1.5 days after birth (OR=2.6, 95% CI: 1.2-5.7, p=0.01) and if the piglets were castrated when more than 14 days old (OR=2.7, 95%CI: 1.1-6.8, p=0.03). A temperature range of less than 5°C for the ventilation control rate in the farrowing room (OR=2.7, 95% CI: 1.2-5.9, p=0.01), a mean temperature in the finishing room below 23°C (OR=3.0, 95% CI: 1.3-6.8, p<0.01) and large herd size (OR=3.1, 95% CI: 1.4-6.9, p<0.01) were also associated with increased risk of pleuritis. The factors affecting pneumonia and pleuritis seemed to be different. All rearing steps from farrowing to finishing must be taken into account in any health programme aimed at controlling pneumonia and pleuritis and lung health may be improved through several pathways, i.e. correcting managerial and hygienic factors, implementing an appropriate and well-functioning ventilation in order to offer favorable climatic conditions.     

Single-Electron Transport in Ropes of Carbon Nanotubes

The electrical properties of individual bundles, or "ropes," of single-walled carbon nanotubes have been measured. Below about 10 kelvin, the low-bias conductance was suppressed for voltages less than a few millivolts. In addition, dramatic peaks were observed in the conductance as a function of a gate voltage that modulated the number of electrons in the rope. These results are interpreted in terms of single-electron charging and resonant tunneling through the quantized energy levels of the nanotubes composing the rope.     

Effects of N,N-dimethylglycine on cardiorespiratory function and lactate production in thoroughbred horses performing incremental treadmill exercise

In a crossover study, either a placebo paste or N,N-dimethylglycine was administered orally at a dose rate of 1.2 mg/kg twice daily for five days to six thoroughbred horses, with bodyweights ranging from 424 to 492 kg. Using previously determined regression equations for oxygen uptake (VO2) against speed for each horse, a standardised exercise test was given with speeds equivalent to fixed percentages of the maximum oxygen uptake (VO2max). The test consisted of two minutes at speeds equivalent to approximately 40 per cent and 50 per cent VO2max, and one minute at speeds that produced approximately 60, 70, 80, 90 and 100 per cent VO2max. During the last five seconds of each exercise stage, the values of VO2, carbon dioxide production (VCO2), heart rate, arterial blood and plasma lactate concentrations, arterial blood gases and pH were measured. Before and immediately after the exercise test, muscle biopsies were collected from the middle gluteal muscle to determine the muscle lactate concentrations. The administration of N,N-dimethylglycine produced no significant differences in any of the measured values, and it is concluded that the compound has no beneficial effects on cardiorespiratory function or lactate production in the exercising horse.     

Infectious agents associated with respiratory diseases in 125 farrow-to-finish pig herds: a cross-sectional study

A study was carried out in 125 farrow-to-finish pig herds to assess the relationships between pathogens involved in respiratory disorders and to relate these findings to clinical signs of respiratory diseases and pneumonia and pleuritis at slaughter. Clinical examination and sampling were carried out on four different batches in each herd (pigs aged 4, 10, 16 and 22 weeks). Mycoplasma hyopneumoniae, Actinobacillus pleuropneumoniae, swine influenza viruses (SIV), porcine reproductive and respiratory syndrome virus (PRRSV) and porcine circovirus type 2 (PCV2) were detected by serological or PCR tests. Pneumonia-like gross lesions and pleuritis were scored at the slaughterhouse. The results indicate that the percentage of pigs PCR-positive for PCV2 at 4, 10 and 16 weeks old was associated with the percentage of pigs PCR-positive for M. hyopneumoniae at these ages. On the other hand, the percentage of pigs with antibodies against PRRSV at 10, 16 and 22 weeks was positively correlated with the percentage of pigs seropositive for M. hyopneumoniae at 22 weeks, with the percentage of pigs with antibodies against SIV H1N1 and SIV H1N2 and the percentage of pigs sero-positive for A. pleuropneumoniae serotype 2. The findings also indicate that, within the five studied pathogens, M. hyopneumoniae, PRRSV and SIV H1N1 are the major pathogens involved in pneumonia-like gross lesions even though PCV2 may play a role. A. pleuropneumoniae serotype 2, in association with PRRSV, is significantly associated with extensive pleuritis. Respiratory diseases could be significantly reduced by implementing measures including appropriate management practices to control these pathogens.     

Confirmation of resistance to ivermectin by Cooperia curticei in sheep

AIM: To investigate the occurrence of resistance to a full dose of oral ivermectin by Cooperia curticei in sheep.

METHODS: Twelve lambs on a sheep and cattle property in the North Island of New Zealand were randomly allocated to one of two equal-sized groups. One group was treated orally with a single dose of ivermectin at the manufacturer's recommended dose rate of 0.2 mg/kg, while the other remained as an untreated control. Worm counts were carried out post mortem on the abomasa and small intestines of all animals in both groups 7 days after treatment.

RESULTS: While treatment with ivermectin reduced the numbers of all other worm genera to almost zero, those of Ostertagia (= Telodorsagia) circumcincta and C. curticei were reduced by only 37% and 19%, respectively.

CONCLUSIONS: These results provide clear evidence of resistance to ivermectin by O. circumcincta and C. curticei. They also appear to represent the first record of macrocylic lactone (ML) resistance in C. curticei in sheep in New Zealand or elsewhere.     

Underground power transmission

Much of the generating capacity to meet the needs of the future may be from generating stations in groups of two or three, each of 1000 Mw, located away from the growing urban areas. Transmission systems will become longer and be of higher duty; and a combination of popular demand and land cost will force the system underground at increasing distances from cities. The need for higher capacity cables to match the new overhead systems and for reduced capital and installation costs is forcing the search for better materials and new techniques. The vast size of the power industry implies that a breakthrough in technology would have dramatic consequences and even a small improvement in materials or techniques can be of significant economic importance.     

Biooxidation of added and natural hydrocarbons in soils: Effect of iron

The decomposition of pure hydrocarbons in soils depends essentially on the intrinsic biological activity of the soils. Seasonal variations were observed, but other environmental factors, such as acidity, were more important. In non-acid soils, the structure of the hydrocarbons was secondary, whereas in acid soils, the rate of decomposition was much slower and depended on their chain length. The difference was reflected, in characteristic soils, in the natural distribution of the hydrocarbons, which originate predominantly from plant decay.Two acid soils, supplemented with ferric hydroxide, were incubated for 16 weeks at 28°C and their hydrocarbon fraction analyzed. Iron enrichment did not lead to complete biodegradation but rather to stimulation of the biooxidation of unbound hydrocarbons and to disppearance of the chain length discrimination. Conversely, the bound alkanes were stable towards microbial activity, with only the amounts of short chain hydrocarbons being slightly reduced.