Weeks In Sites Research Articles

Raising goats in the southern-pine silvopasture system: challenges and opportunities

Pasture-based goat operation is popular among small-scale farmers; however, it may be challenging when forage availability is limited. Grazing opportunity can be increased by developing silvopastures after thinning pine plantations. To successfully manage silvopastures, it is important to understand animals’ interaction with trees. The objective of this study was to evaluate the use of goats in the southern pine silvopasture system. Studies were conducted at two sites: Atkins Agroforestry Research and Demonstration Site, Tuskegee (Site 1), and Plantersville Silvopasture Demonstration Site, Plantersville, Alabama (Site 2). Site 1 consisted of six acres of longleaf (Pinus palustris Mill.) and loblolly (Pinus taeda L.) pine trees (10–11 years old, 147 ± 21.1 trees/acre; longleaf 52.14%, loblolly 47.86%). Site 2 comprised of 14 acres of 17–18 years old loblolly pine silvopastures. Both sites were planted with cool- and warm-season forages, and plots were rotationally grazed with goats (Site 1—Kiko wethers; Site 2—mixed breed of goats) during the 2015–2016 grazing seasons. Goat performance (live weight, body condition score, and FAMACHA score) was monitored every 2 weeks in Site 1, and trees were inspected for possible damage in both sites. Goats performed better while grazing cool-season forages during the spring. In Site 1, goats debarked pine trees, especially longleaf pines during the cool-season grazing period. No debarking was observed in Site 2. This study showed that southern pine silvopastures could provide a good grazing opportunity, but trees can be vulnerable to goats even when they are 10–11 years of age.

Guided Bone Regeneration for Socket Preservation in Molar Extraction Sites: Histomorphometric and 3D Computerized Tomography Analysis

Guided Bone Regeneration for Socket Preservation in Molar Extraction Sites: Histomorphometric and 3D Computerized Tomography Analysis

Evaluation of an injectable rhGDF‐5/PLGA construct for minimally invasive periodontal regenerative procedures: a histological study in the dog

To evaluate the injectability, biocompatibility, safety, and periodontal wound healing/regeneration following application of a novel bioresorbable recombinant human growth/differentiation factor-5 (rhGDF-5)/poly(lactic-co-glycolic acid) (PLGA) construct. Periodontal pockets (3 x 6 mm, width x depth) were surgically created over the buccal roots of the second and fourth mandibular pre-molars in eight adult Hound Labrador mongrel dogs. Surgeries including injection of the rhGDF-5/PLGA construct into the pockets were sequenced that four animals provided 2-/4-week and four animals 6-/8-week observations of sites receiving rhGDF-5/PLGA or serving as sham-surgery control. The rhGDF-5/PLGA construct was easy to prepare and apply. Approximately 0.2 ml (93 microg rhGDF-5)/tooth was used. Clinical and radiographic healing was exemplary without adverse events. Healing was characterized by a non-specific connective tissue attachment, acellular/cellular cementum, periodontal ligament (PDL), bone regeneration, and a junctional epithelium. PLGA fragments were observed in 4/7, 2/8, and 1/8 sites at 2, 4, and 6 weeks, respectively. Associated inflammatory reactions exhibited no limiting effect on periodontal wound healing/regeneration. Root resorption/ankylosis was not observed. Bone formation showed apparent increased maturity (lamellar bone) at 6 weeks in sites receiving rhGDF-5/PLGA compared with the control. Both protocols exhibited significant increases in PDL, cementum, and bone regeneration over time, without significant differences between treatments. In time, PDL and cementum regeneration was twofold greater for the control at 4 weeks (p=0.04) while increased bone formation was observed at sites receiving rhGDF-5/PLGA (p<0.01). In conclusion, the rhGDF-5/PLGA construct appears to be a safe technology for injectable, ease-of-use application of rhGDF-5-stimulated periodontal wound healing/regeneration. Additional work to optimize the polymer carrier and rhGDF-5 release kinetics/dose might be required before evaluating the efficacy of this technology in clinical settings using minimally invasive approaches.

Analysis of rat calvaria defects implanted with a platelet‐rich plasma preparation: histologic and histometric observations

It has been suggested that degranulating platelet alpha-granules release growth factors having a potential to modulate bone formation. The objective of this study was to evaluate the osteoconductive potential of a platelet-rich plasma (PRP) preparation. Thirty adult male Sprague-Dawley rats were used. The PRP preparation was obtained from 10 ml of whole blood drawn from one age-matched donor rat. The preparation was processed by gradient density centrifugation and stored at -80 degrees C until use. Using aseptic techniques, the PRP preparation soak loaded onto an absorbable collagen sponge (ACS) or ACS alone was surgically implanted into contralateral critical size 6-mm calvaria osteotomies in 18 animals. Twelve animals received ACS versus sham surgery in contralateral defects. Animals were sacrificed at 4 and 8 weeks when biopsies were collected for histologic and histometric analysis. The animals were maintained without adverse events. Bone formation was highly variable in sites receiving PRP and control treatments. Defect bone fill at 4 weeks averaged (+/-SD) 28.8+/-27.4% (PRP/ACS) versus 39.1+/-24.4% (ACS; p=0.2626) and 62.0+/-20.0% (ACS) versus 71.6+/-32.2% (sham surgery; p=0.1088), and at 8 weeks 81.0+/-12.9% (PRP/ACS) versus 64.5+/-28.1% (ACS; p=0.2626) and 75.6+/-34.1% (ACS) versus 74.1+/-24.2% (sham surgery; p=0.7353). Remnants of the ACS biomaterial were observed at both 4 and 8 weeks in sites implanted with PRP/ACS or ACS. The results suggest that the PRP preparation has a limited potential to promote local bone formation.