Reproductive Performance, Udder Health, and Antibiotic Resistance in Mastitis Bacteria isolated from Norwegian Red cows in Conventional and Organic Farming

<p>Abstract</p> <p>Background</p> <p>The objectives of this study were to investigate whether there were differences between Norwegian Red cows in conventional and organic farming with respect to reproductive performance, udder health, and antibiotic resistance in udder pathogens.</p> <p>Methods</p> <p>Twenty-five conventional and 24 organic herds from south-east and middle Norway participated in the study. Herds were matched such that geographical location, herd size, and barn types were similar across the cohorts. All organic herds were certified as organic between 1997 and 2003. All herds were members of the Norwegian Dairy Herd Recording System. The herds were visited once during the study. The relationship between the outcomes and explanatory variables were assessed using mixed linear models.</p> <p>Results</p> <p>There were less > 2nd parity cows in conventional farming. The conventional cows had higher milk yields and received more concentrates than organic cows. Although after adjustment for milk yield and parity, somatic cell count was lower in organic cows than conventional cows. There was a higher proportion of quarters that were dried off at the herd visit in organic herds. No differences in the interval to first AI, interval to last AI or calving interval was revealed between organic and conventional cows. There was no difference between conventional and organic cows in quarter samples positive for mastitis bacteria from the herd visit. Milk yield and parity were associated with the likelihood of at least one quarter positive for mastitis bacteria. There was few <it>S. aureus </it>isolates resistance to penicillin in both management systems. Penicillin resistance against Coagulase negative staphylococci isolated from subclinically infected quarters was 48.5% in conventional herds and 46.5% in organic herds.</p> <p>Conclusion</p> <p>There were no large differences between reproductive performance and udder health between conventional and organic farming for Norwegian Red cows.</p

One and four layer acellular bladder matrix for fascial tissue reconstruction

To determine whether the use of multiple layers of acellular bladder matrix (ABM) is more suitable for the treatment of abdominal wall hernia than a single layered ABM. The feasibility, biocompatibility and mechanical properties of both materials were assessed and compared. Biocompatibility testing was performed on 4 and 1 layered ABM. The matrices were used to repair an abdominal hernia model in 24 rabbits. The animals were followed for up to 3 months. Immediately after euthanasia, the implant site was inspected and samples were retrieved for histology, scanning electron microscopy and biomechanical studies. Both acellular biomaterials demonstrated excellent biocompatibility. At the time of retrieval, there was no evidence of infection. The matrices demonstrated biomechanical properties comparable to native tissue. Three hernias (25%) were found in the single layer ABM group and only 1 hernia (8%) was found in the 4 layer ABM group. Histologically, the matrix structure was intact and the cell density within the matrices decreased with time. The dominant cell type present within the matrices shifted from lymphocytes to fibroblasts over time. Both ABMs maintained adequate strength over time when used for hernia repair, and there was an extremely low incidence of adhesion formation. The single layer ABM showed enhanced cellular integration, while the 4 layer ABM reduced hernia formation. Either of these matrices may be useful as an off-the-shelf biomaterial for patients requiring fascial repair