Modelling the determinants of grassland stocking rates on dairy farms in England and Wales

An attempt has been made to provide a quantitative model of grassland management on a dairy farm which could be used for predictive purposes to establish appropriate stocking rates in relation to the resources available and the consequences of changing the level of resources used. The model takes into account the effect of rainfall, the available water capacity of the soil, soil drainage and fertiliser usage on grass production and the calving pattern, milk yield and availability of other feeds in determining grass requirements. Allowance is made for the fact that the response to unpredictable variation in grass production may be to under-stock. There was reasonably good agreement between predicted and actual stocking rates for a group of 33 dairy farms, but the predictions were too variable for acceptance of the model as a reliable aid in management planning on individual farms. Nonetheless, the model showed sufficient promise to suggest that it may be feasible to make predictions for individual farms in the future if a clearer understanding of a number of aspects of grassland management can be obtained: most notably, how farmers respond to risk, how managerial ability and financial constraints affect stocking intensity and how farmers integrate, in practice, grazing and conservation.     

Diagnostic findings and prognosis following arthroscopic treatment of subtle osteochondral lesions in the shoulder joint of horses: 15 cases (1996-1999)

OBJECTIVE: To determine clinical, scintigraphic, radiographic, and arthroscopic findings and results of treatment in horses with lameness attributable to subtle osteochondral lesions of the shoulder joint. DESIGN: Retrospective study. ANIMALS: 15 horses. PROCEDURE: Medical records were reviewed, and results of physical examination, scintigraphy, radiography, arthroscopy, and treatment were recorded. RESULTS: Severity of lameness ranged from grade 1 to 4. Response to shoulder flexion or extension was variable. Twelve horses had a narrow upright foot. Intra-articular anesthesia of the shoulder joint localized the cause of the lameness to the shoulder joint in 9 of 10 horses. Scintigraphic abnormalities were detected in 4 of 6 horses. Radiographic lesions were subtle and included glenoid sclerosis, focal glenoid lysis, small glenoid cysts, and alterations in the humeral head contour. Arthroscopic evaluation confirmed clefts in the glenoid cartilage, glenoid cysts, a humeral head cyst, fibrillation of the humeral head cartilage, cartilage fragmentation, or a nondisplaced fracture of the humeral head. After treatment, 12 horses returned to their previous level of performance, 1 was sound for light riding, 1 remained lame, and 1 was euthanatized because of chronic lameness. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that a combination of physical examination, scintigraphy, and radiography is necessary to diagnose subtle osteochondral lesions of the shoulder joint in horses. Arthroscopy can be used to confirm the diagnosis and treat cartilage and subchondral bone lesions. Young and middle-aged horses with subtle osteochondral lesions of the shoulder joints have a good prognosis for return to performance following arthroscopic treatment.     

Miocene glaciomarine sediments from beneath the southern ross ice shelf, antarctica

Glaciomarine sediments with middle Miocene microfaunal assemblages are exposed at the sea floor below the southern Ross Ice Shelf. Plio-Pleistocene sediments are not present. Post-Miocene glacial sediments may have been deposited but removed by relatively recent ice shelf grounding. A meager Recent microfauna is present in some core tops.     

An H-NS-like stealth protein aids horizontal DNA transmission in bacteria

The Sfh protein is encoded by self-transmissible plasmids involved in human typhoid and is closely related to the global regulator H-NS. We have found that Sfh provides a stealth function that allows the plasmids to be transmitted to new bacterial hosts with minimal effects on their fitness. Introducing the plasmid without the sfh gene imposes a mild H-NS(-) phenotype and a severe loss of fitness due to titration of the cellular pool of H-NS by the A+T-rich plasmid. This stealth strategy seems to be used widely to aid horizontal DNA transmission and has important implications for bacterial evolution.