Osteochondrosis of the elbow: a review of the pathogenesis and a new approach to treatment

SUMMARY To test the hypothesis that joint incongruity contributes to the pathogenesis of elbow osteochondrosis, the left and right radius and ulna of 20 young large breed dogs were measured to determine any variation in length and to observe any incongruity of the elbow joint. Both lame and normal dogs were included in the study. Nine of the 20 dogs had marked disparity in radial and ulnar lengths yet only one had obvious elbow joint incongruity. The use of a sliding osteotomy for the treatment of fragmented coronoid process and a lengthening osteotomy for the treatment of an ununited anconeal process is also discussed. All four dogs treated with a sliding osteotomy showed a marked clinical improvement, and two of the three dogs treated with a lengthening osteotomy showed radiographic fusion of the anconeal process.     

Microbial immobilisation of C rhizodeposits in rhizosphere and root-free soil under continuous C labelling of oats

A greenhouse experiment was conducted by growing oats (Avenasativa L.) in a continuously ¹³CO₂ labeled atmosphere. The allocation of ¹³C-labeled photosynthates in plants, microbial biomass in rhizosphere and root-free soil, pools of soil organic C, and CO₂ emissions were examined over the plant's life cycle. To isolate rhizosphere from root-free soil, plant seedlings were placed into bags made of nylon monofilament screen tissue (16 μm mesh) filled with soil. Two peaks of ¹³C in rhizosphere pools of microbial biomass and dissolved organic carbon (DOC), as well as in CO₂ emissions at the earing and ripeness stages were revealed. These ¹³C maxima corresponded to: (i) the end of rapid root growth and (ii) beginning of root decomposition, respectively. The δ¹³C values of microbial biomass were higher than those of DOC and of soil organic matter (SOM). The microbial biomass C accounted for up to 56 and 39% of ¹³C recovered in the rhizosphere and root-free soil, respectively. Between 4 and 28% of ¹³C assimilated was recovered in the root-free soil. Depending on the phenological stage, the contribution of root-derived C to total CO₂ emission from soil varied from 61 to 92% of total CO₂ evolved, including 4-23% attributed to rhizomicrobial respiration. While 81-91% of C substrates used for microbial growth in the root-free soil and rhizosphere came from SOM, the remaining 9-19% of C substrates utilized by the microbial biomass was attributable to rhizodeposition. The use of continuous isotopic labelling and physical separation of root-free and rhizosphere soil, combined with natural ¹³C abundance were effective in gaining new insight on soil and rhizosphere C-cycling.     

Nitrous oxide emissions from fertilized,irrigated cotton (Gossypium hirsutum L.) in the Aral Sea Basin,Uzbekistan: Influence of nitrogen applications and irrigation practices

Nitrous oxide emissions were monitored at three sites over a 2-year period in irrigated cotton fields in Khorezm, Uzbekistan, a region located in the arid deserts of the Aral Sea Basin. The fields were managed using different fertilizer management strategies and irrigation water regimes. N₂O emissions varied widely between years, within 1 year throughout the vegetation season, and between the sites. The amount of irrigation water applied, the amount and type of N fertilizer used, and topsoil temperature had the greatest effect on these emissions.Very high N₂O emissions of up to 3000 μg N₂O-N m^?2 h^?1 were measured in periods following N-fertilizer application in combination with irrigation events. These “emission pulses” accounted for 80–95% of the total N₂O emissions between April and September and varied from 0.9 to 6.5 kg N₂O-N ha^?1.. Emission factors (EF), uncorrected for background emission, ranged from 0.4% to 2.6% of total N applied, corresponding to an average EF of 1.48% of applied N fertilizer lost as N₂O-N. This is in line with the default global average value of 1.25% of applied N used in calculations of N₂O emissions by the Intergovernmental Panel on Climate Change.During the emission pulses, which were triggered by high soil moisture and high availability of mineral N, a clear diurnal pattern of N₂O emissions was observed, driven by daily changes in topsoil temperature. For these periods, air sampling from 8:00 to 10:00 and from 18:00 to 20:00 was found to best represent the mean daily N₂O flux rates. The wet topsoil conditions caused by irrigation favored the production of N₂O from NO₃^? fertilizers, but not from NH₄⁺ fertilizers, thus indicating that denitrification was the main process causing N₂O emissions. It is therefore argued that there is scope for reducing N₂O emission from irrigated cotton production; i.e. through the exclusive use of NH₄⁺ fertilizers. Advanced application and irrigation techniques such as subsurface fertilizer application, drip irrigation and fertigation may also minimize N₂O emission from this regionally dominant agro-ecosystem.     

After nasopharyngeal infection,foot-and-mouth disease virus serotype A RNA is shed in bovine milk without associated mastitis

Foot-and-mouth disease (FMD) is a highly contagious aphthoviral infection of cloven-hoofed animals, inducing vesiculopustular stomatitis, pododermatitis, and thelitis. Vesicular fluid represents a major pathway of virus excretion, but bovine milk is another important source of virus shedding. We describe here the time course of FMD virus (FMDV) excretion in the milk and characterize associated lesions in the mammary gland. Three dairy cows were infected by nasopharyngeal instillation of FMDV and monitored over 12 d. Autopsy was performed at the end of the study, and specimens were collected for histopathology, IHC, and RT-qPCR. All 3 cows developed fever, drooling, vesiculopustular stomatitis, interdigital dermatitis, and thelitis. FMDV RNA was detectable in whole milk until the end of the trial, but only transiently in saliva, nasal secretions, and blood serum. Although histology confirmed vesiculopustular lesions in the oral and epidermal specimens, the mammary glands did not have unequivocal evidence of FMDV-induced inflammation. FMDV antigen was detectable in skin and oral mucosa, but not in the mammary gland, and FMDV RNA was detectable in 9 of 29 samples of squamous epithelia but only in 1 of 12 samples of mammary gland.